#151 - Alex Hutchinson, Ph.D.: Translating the science of endurance and extreme human performance

Hey everyone. Welcome to the Drive Podcast. I'm your host, Peter Attia. This podcast, my website and my weekly newsletter all focus on the goal of translating the science of longevity into something accessible for everyone. Our goal is to provide the best content in health and wellness, full stop, and we've assembled a great team of analysts to make this happen. If you enjoy this podcast, we've created a membership program that brings you far more in depth content. If you want to take your knowledge of this space to the next level, at the end of this episode, I'll explain what those benefits are. Or if you want to learn more now, head over to peterattiamd.com subscribe Now without further delay. Here's today's episode. My guest this week is Alex Hutchinson. Alex is a science sports journalist who writes about the science of running and other endurance sports. Before getting his master's master's degree in journalism from Columbia University, he received his PhD in physics from the University of Cambridge. He's a lifelong runner and we start this podcast by talking about his incredible passion for running, which he did competitively until about the age of 28. I first got familiar with Alex's work reading a number of his articles, but became really obsessed when I read his book Endure early in 2019. I believe it came out the year before. It's a wonderful story about the science of endurance and what the real limits are of human performance. And since that time I just knew I always wanted to have him on the podcast to talk about this with him. In this episode we talk about a number of things. We kind of talk about his background, which is how does a guy go from having a PhD in physics to deciding he wants to go and do journalism, and then kind of go from doing sort of the beat journalism stuff to getting into science and the science of endurance? And then we just talk a lot about stuff that people have asked me so many questions about and we go into it in really tremendous detail, such as VO2 max and what does it mean and how much of it is genetic and does it automatically imply superior performance, even some of the nuances of how it's measured? We talk about the difference between maximum aerobic capacity and efficiency, and then we kind of transition into what these things mean for normal people. So we obviously talk about the extreme examples of human performance. We talk a lot about breaking the two hour marathon, which is something that was done recently in 2019, and then kind of bring it back to what all of this means in terms of health. We get into the idea of challenging the idea that one can exercise too much and challenging the J curve of mortality, discussing how maybe there are different ways to think about this problem. We talk about high intensity interval training and a whole bunch of other things that I think you'll find really interesting. So without further delay, please enjoy my conversation with Alex Hutchinson. Alex, thanks so much for making time today to sit down and be part of our inaugural video podcast here. I hope it's not a long run for a short slide. So far it's been a long run, but I have a feeling it's going to be a long slide, too.

Well, thanks for having me on, Peter. I really appreciate it. And this is going to be fun.

So about two years ago, was it two years ago? Yeah, it would have been. It would have been like February of 19. I read your book Endure, which I literally couldn't put down. I think I read it in two days. It was fantastic. And since that time, I've become such a huge fan. You're a very prolific writer. I don't know how you do it. If you just search your name and go through all the magazine articles you write, it's just a wonder you can do so much. There are so many things I want to talk about today, but I want to kind of start with just a bit of your background, because you don't have a typical background, Right. You have a PhD in physics.

Yeah. Probably the least useful PhD in physics anyone has ever attained. But, yeah, no, I come from a different place. In some ways, I would say you're.

A collegiate runner and we actually have some friends in common because I think we're of the same generation. Remind me, did you go to Waterloo? Did you go to Guelph? Where did you go to college?

I went to McGill for undergrad and then grad school in England. But, yeah, we come from the same part of the world. It's a small pool. So I think we've interacted with a few of the same people.

Yeah. And I think some of my friends probably ran cross country against you and ran track and stuff like that. So for how long was track sort of your passion?

I would say it was the most important thing in my life until I was 28. Until that point, I would have put anything and everything aside if it meant. I mean, I'm embarrassed to say it now. I made my brother reschedule his wedding for a track meet. After 28, I kept training seriously until my early 30s. I still run six days a week, train, race, all that. But 28, until then, it was the Most important thing in my life.

And when did that start? What age were you? Was this sixth grade? How serious were you in grade school?

I like to say I did win a race in senior kindergarten. I beat Stephen Mills, who's a nice kid, but a big kid. And I was like, wow, I beat the big kid. So I've always been the guy who liked to run around. And I ran elementary school cross country, which involved showing up for a race once a year. And I did well in that. I joined a track club When I was 15, the University of Toronto Track Club, with the idea that I would train for three months because I was in a lucky position because my birthday was after September 1st, so I could compete with the people a year younger than myself. And I thought, well, let's, you know, let's use leverage. Every edge I've got. I'll train hard for these three months, see if I can stomp on these grade nines. And it worked. I ran well and I kind of got hooked and realized that I wasn't going to quit after three months.

Where did you go to high school in Toronto.

I went to a school called University of Toronto Schools, which is a very, very small school. It's academically focused from an athletic perspective. The really nice thing is if you want to be on a team, you're on the team. The qualifying process for school teams was going through the hallways and basically press gangs, trying to get enough people for a team.

When you went to college, obviously McGill is a great academic school in Canada. They don't have athletic scholarships. Was it a difficult decision to say, hey, I'm going to stay in Canada for university or try to go to a US school where I could sort of parlay some of my running talents to actually get some money for school?

There's a couple of factors that played into that. One is that I got mononucleosis in my last year of high school. I missed basically my entire final year of high school. So I was a very, very good grade 11 runner. And then back then in Ontario, there were 13 grades, but the high school I went to only went up to grade 12, basically. So I graduated from high school without ever having competed as a senior in high school. That's a long, rambling way of saying I wasn't good enough to get a scholarship to any reasonable place in the United States. So that discussion wasn't even really open to me whether I would have. It's an alternative scenario that I would have been attracted by the idea for sure, but that door wasn't open to me.

Anyway, when you showed up at McGill, what was sort of your specialty? I know you were a miler. How competitive were you at the 800? How competitive were you at 5k and other distances away from the mileage?

I was a 1500 meter runner when I showed up and with the assumption that I would be moving up to 5,000, you know, any minute now that I didn't, I didn't have a lot of sprint speed. I was a strength oriented 1500 meter runner. As it turns out the coach at McGill was an ex 400 meter, 400, 800 guy and his training was very sprint oriented. It was, it was long recoveries and all out intervals and so I actually ran better at 800 than I expected I would. But I, it was pretty clear that 1500 was kind of the low end of my sweet spot.

I had so many friends who ran and many of them said that the 800 was the most painful race there was. And I guess in swimming that's comparable to the 200. I think there's something to be said for that. That sub 2 minute all out effort is really an unpleasant physiologic existence which we're going to talk a lot about that physiology but would you agree with that? Having run so many distances, a hundred.

Percent, 100%, the, the most painful race that I could run was the 800. And you know, I, and I also think about this in the context of workouts, specifically you know, at McGill, talking about more sprint oriented workouts, longer rest, these sort of hard two minute efforts. If I wanted an easy workout, the intuition would be like you want to ask your coach for more recovery or whatever. And I, it was the opposite for me. It's like if, if the workout seemed too hard I'd be can we cut the rest in half? Because then I know we're not going to be in that very high lactate regime which is, you know, a two minute all out effort is the single way to get the highest possible lactate levels. And to me that's synonymous with extreme suffering. I'd rather run a marathon than an 800 in some ways.

Yes. I found when I used to tweak around with lactate levels, I found that my personal best, as though highest lactate was doing a 200 IM in swimming 200 individual medley because it's upper and lower body with all four strokes it's that 200. So two minutes of unbearable pain, your personal best lactate could be achieved with that personal worst.

Call it. And yeah, I think that's something a lot of people don't. There's an assumption that longer equals harder. And it's like man. No, there's a whole different world of pain that you can get into if you're willing to push yourself hard in those two minute efforts. Two to ten minute efforts, call it.

Now, in your book Endure, you talk about a very interesting, almost a throwaway meet. We would call these dual meets in swimming. Right. And it was sort of, again, I don't know if this was the turning point for you, but it's sort of as you read it, it comes across as a moment when you first realize there's more to this than just the numbers. Like there's something going on in my head that is changing the speed that I run in. Was that the. I mean, I want to hear the story. I want people to hear the story, but was that a big aha moment for you or was that just the first of many steps along a pathway?

I'd say it was a huge aha moment for me at that time, but I'm not sure I understood what the aha was. I knew that this, like, this is strange and in hindsight I realized that this is what was that. I'm sure we'll dig into this. But it was, you know, this started my movement away from. Just like we can calculate everything from physiology, that endurance is a little more complicated than the equations that you might start with.

Well, tell the story because it's, I mean, again, you write about it so eloquently, but it's kind of hard to believe, especially as someone who, I'm not a runner and I'm not good at anything, but I still understand physiology quite well. And as the story's unfolding, you're thinking there's a mistake. So, yeah, walk us through that night.

As you said, totally meaningless meet. Didn't have any big goals, but I was at that point. This was third year university and for about four years, almost three and a half years, I'd been running between 401, 402, 403 for 1500 meters. 1500 meters is about 17 seconds shorter than a mile. So we're talking like it's kind of like the poor man's four minute mile. It's a significant barrier for runners, but it's not at the level of a four minute mile. And so for me it was like that was kind of a career goal. I wanted to break four minutes. If I could get into the threes, I felt like, okay, I, I would have achieved something significant. But like I said, ever since high school, I'd been running very close, couldn't quite do it. And at this meaningless meet there was no competition whatsoever. It was going to be, I was going to win the race no matter what. And it's sort of at the last minute I decided, well, I might as well go hard and just see what I can do. And I'm unlikely to do anything special in this context, but I'll go hard. And indoor track is 200 meters long, so you get splits every bo 30 seconds. And I came through the first lap and the timekeeper called out 27 seconds for 200 meters, which is, it's about five seconds faster than four minute pace, which is an eternity, an absolute eternity. 27 seconds is extremely fast and it's a terrible way to start a 1500 meters race if you're trying to run sub four minutes. And so I had, you know, conflicting motions of like, oh God, you idiot. With oh. I actually feel surprisingly relaxed. But I need to dial it back.

Because presumably, alex, you'd run 27s in practice as splits and you know what 27 feels like. And so on some level you're thinking, I feel really good because this doesn't feel as fast as 27. Right?

Yeah, you're dialed into what 27 should feel like. But, and this is maybe an early clue, you also know that nothing feels the same in a race, that there's some magic that happens in a race and something that should have felt impossible will feel relaxed. And so you can kind of dismiss those discrepancies and say, well, this is the magic of the race. We don't know where it comes from, but it's the magic. And same thing. In the second lap, I came through in 57 seconds, which is way too fast, but I still felt relatively like good. And third lap 1:27. And so at that point the two things were happening. One is I realized I was having a really good day. And two, I realized that I, the splits were no longer meaningful to me because, you know, you memorize the splits for the races you think you're going to run. At that point I didn't know what 1:27 extrapolated to. And so the best decision I maybe made in my racing life was like, stop listening to the splits. This is a special day run. Just put your head down and go for it. So I, I did stop listening to the splits and I, I hammered home and I ran 3:52, which was, yeah, nine seconds faster than my personal best at the time. And Again, you really have to emphasize that a one second personal best would have been a huge victory for me. And nobody PBS by nine seconds after they've been training hard for four years, five years. So it was just absolutely mind boggling. And you know, to cut to the chase, the postscript of the story is chatting to one of my teammates afterwards who had taken my splits for me so that I could as, as you do, you put them in your training log and you plot them in Lotus 1, 2, 3 and you analyze them obsessively for months. So I wanted to get my splits and he's like, yeah, pretty good race. And I was like, yeah, I can't believe I went out in 27 seconds. You didn't go out in 27 seconds. You were like 30 seconds. What? Second lap, 60 seconds, what? So at the time, my theory was that this was a meet in Quebec, in Sherbrooke. And so it's like, oh, the guy was maybe translating from French to English and there was a three second lag. Maybe he just missed the start with his watch. I don't know what happened, but he basically tricked me. He fooled me into thinking I was having this amazing day and then I did. In itself, that was a very bizarre circumstance. And then the question is, what happens after that? Do I become a four minute runner again or can I run 352 again? And the answer is neither. I ran 3:49 in my next 1500 and I ran 3:44 in the race after that, which qualified me for the Olympic trials that summer. So that's why I say you asked, was this an aha moment? And it's like I knew right at the time. It's like something has changed. It changed my career as an athlete. But then in hindsight, I realized it also changed my understanding of what this whole endeavor was about and what we were trying to optimize.

I mean, again, I still sort of struggle with that. And of course you want to extrapolate that. Does the same thing apply to strength sports? Well, presumably it does, right? Could you easily trick somebody into thinking, someone who thinks, oh, I could just never break 500 pounds for a deadlift, and they're sort of forever stuck at £495. But is there anything really preventing them from deadlifting £550, which would be as much of a breakthrough if they simply believe that that's how much weight was on. If they simply believed that it was only £475 on the bar.

I should add a postscript here. The book Came out my old coach from high school, who I've. I continue to stay in touch with. He's a very big influence in my life. He read the book and he's like, show me your training log. Which lots of people have said, right? Like, come on, this wasn't all in your head. And I was like, okay, here's my training log. You remember it. Check it out. You. You tell me, was I ready to run 352. Because there wasn't a big discontinuity in my training. It wasn't like I knew I was fitter, I knew I should be able to break four minutes, but there wasn't. Like, I. I suddenly was doing workouts way faster. And he looked through it, and his conclusion was, you know what, Alex? You were in shape to run. Mid three 50s for sure. You were not in shape to run. You were not doing workouts that predicted 3:44. So in a way, the first breakthrough might have been, in some ways, just catching up to the ways I was holding myself back. I was overthinking things, stressing out all these things that people do in competitive scenarios. I caught up to what I should be doing, and then that gave me so much confidence that I kind of slingshotted right past where I should have been. And I was able to. You know, there's always a conversion between what are you doing in. In workouts versus what can you do in races? Everyone should be able to do more in a competitive scenario than they can do on a rainy Tuesday night in Stoke or whatever. And I think the best conversions I ever had, the time when I was competing the farthest above my sort of baseline workout fitness, was in the months after that breakthrough, because I was just riding that high and I believed I was semi invincible.

So this is 96, right?

Yeah.

So you go to the Olympic Trials for the 1500. How did you run there?

It's on YouTube. It's horrible. I can't remember if it was dead last or 11th in the final. I made the final, which was okay. When I look back to it, I'm on the standing line next to Graham Hood, who's the Canadian record holder at the time. So the camera lingers on Graham Hood, so you can see me the whole time. And I just look, I think I might have written this book. I can't remember, but it looks like I'm like, waking up from a dream and looking around in my pajamas or something like that. You know, I don't belong. I'm there. Or, you know, I don't believe I belong there. A year later I came back to the national championships and by that time I'd had a year to consolidate and no, I belong. I'm a guy who runs in the low 340s and that time I ran well. I came fourth. That was probably my, that was my best finish at outdoor nationals and took a while for my confidence to fully catch up to me. I think that was how that played out.

And did you end up running the actual mile, the 1604 or whatever, the non metric mile? Because you would have by that point broken the four minute mile, right?

You're poking your finger into a raw wound here.

Oh God, I'm sorry.

If you take my best 1500 and you plug it into the official conversions tables, it suggests that I would have run 4 flat 0.01. I deprecate that entirely. I don't believe it at all. I'm confident that on that day I'll go to my grave saying I would have run 359.9 that day. But in terms of miles, the thing is, the mile is just not very frequently run. I ran two competitive miles in my career. One an indoor mile early season when I was in college. And then about four years later, 97, I ran my best. I was that I got a knee injury, was out 98, 99, 2000, 2001. I was trying to come back and it was a slow process. And I ran a mile in Oregon at Hayward Field, which is the sort of most famous place. It's a good place to go sub four, but I did not. I ran like 406. I just wasn't back to my shape yet. And those are the only two miles I ran in my career. And I regret it. It's a big thing. Like four minute mile is. It's a very big thing.

How many people have broken four minutes for the mile roughly in history?

It's a good question. I'm going to say I think it's a few thousand. It's fewer than more people have stood on top of Everest. I think is the thing that people tend to say. I think that's still true. I think there's something like 800 or 900Americans and globally two to 4,000. I could be wrong, but that's my gut memory.

So by the time you're into the mid to late 90s, you're now a PhD student, I'm guessing. Did you go straight into your PhD program?

I went straight there and I did a PhD in Britain, where PhDs are. It's kind of a PhD Lite. It's not as rigorous as a full North American PhD. It's hard in many ways, but it's different. So I did a three year PhD from 97 to 2000.

What was the itch you were scratching there? Were you a physics student in Undergrad?

Yeah, at McGill you have to choose pretty early. And so I did pretty much all physics in second, third and fourth year. I enjoyed it, but this was one of those things for me that I didn't know what I wanted to do. And one of the pieces of advice I got coming out of high school is if you don't know what you want to do, do the hardest thing possible. Because you can study physics and then become a journalist, but you cannot study journalism and then become a physicist. There's a gradient.

You can only slide in one direction.

Yeah, exactly. So I have a brother who's five years older than me, so he was finishing university when I was finishing high school. And I had actually applied in, I think I applied to McGill in history initially. But my brother had a friend who was finishing up in Physics at McGill and she told him that in her class there'd been like 60 men and five women starting the program and they graduated four men and four women. I thought, that sounds hard. I'm switching my major to physics. So that's kind of how that started. And then coming out of undergrad, I really just didn't know what I wanted to do. I applied to a bunch of things again in a variety of fields, but because I'd studied physics in undergrad, the best opportunity I got was to go and do a PhD in physics. And I thought it would be a reasonable way of allowing me to continue my running career and it would be a chance to go overseas and see a new culture and have fun. And I was certainly willing to give physics a shot. I was considering physics as a career, but my decision was framed in a way that even if I left physics, which I did end up in the end doing, I had zero regrets about spending three years in England studying physics.

How did your training change when you went to England versus Canada? What were the biggest changes you experienced?

Yeah, that's actually a really interesting question because there's some huge culture changes in terms of the actual, like, how much do you run and stuff? Not as big a deal. But you get to Cambridge and I show up for that first meeting with the team and I meet the training secretary and I'm like, what do you mean training secretary? Well, he's the guy who's going to set our workouts. What do you mean? Don't we have a coach? It's like, no, the athletic scene, there is student run. So there's a kind of a continuum in many things between the US at one extreme, Britain at the other extreme, and Canada is often in the middle. And so sports in the us, collegiate sports are a big, big deal, as you know, and collegiate sports are a medium deal in Canada and they're not a big deal in the uk. And so going there was an eye opener in many ways. It's like we're going to the national championships, so we have to rent a van and then arrange a youth hostel where we can sleep the night before the championships. Like, that's not how collegiate sports work in the us it's not even how they work in Canada. But the flip side is you have a lot of autonomy and you take responsibility for your training and your success. You're not a sort of acolyte or baby, just being sort of fed what to do from day to day. And so I, you know, I don't have a systematic study to support this, but I think the lifelong retention, the extent to which people develop lifelong habits and lifelong love of sport and activity and competition, I think is much higher because you learn to be autonomous in university as opposed to the classic thing in the US is you're there for four years, you're representing your college, and then college ends and it's like, all right, I'm going to go work a job. There's no encouragement to stay involved in sport and you haven't developed the skills required to self motivate, self organize, book that youth hostel or whatever the case may be. So that was the biggest change, I'd say.

So as you're wrapping up your PhD in physics, you have to make another decision, right, which is, am I going to go back to the US or Canada, do a postdoc and then get on, presumably an academic track? Do I want to take this and move into industry where I can utilize this? Because obviously at the time there was probably no shortage of things a PhD in physics could have been doing in Silicon Valley or Wall street, right? Both would have been the heydays, or do something altogether different. So how did you, how did you approach that decision?

I mean, you're right, this was, you know, making these decisions in 99 and early 2000. And my PhD was in semiconductor physics. It was, you know, it was a good time to be in semiconductor physics. And there was also, there's Definitely the pull of both consulting and finance, which is just the same way that it happens with Ivy League students in the States. In Britain, if you're at Oxbridge, they're lining up to offer you vast sums of money. Like I said, at the top, running was the most important thing in my life until I was 28. So I considered some job offers, but I wanted to focus on running. And I was very, very fortunate. I have parents who had a house they were willing to have me move back in and see what happens. So I spent. And at this point I was coming back from this three year injury process. So I had been on a trajectory that I thought was pointing favorably in 98. But then by 2000, when I was finished my PhD, early 2001, I'd been out for a few years and it wasn't clear. And I just wanted to give myself one year to see if I could get back on that track of someone who might have a shot of making the Olympics. So I moved back home. I did some tutoring of high school students, but basically I ran and I went to the library and I checked out. They had a couple racks of world Classics. So I basically went through their entire rack of classic books. You know, 19th century literature, 20th century literature, all the stuff that I didn't get to do as a physics student, as an undergrad. This is not a liberal arts program where I had time to pursue a bunch of things. It was all physics and math. So I spent a year running. It was fun. I qualified for some national teams, I read a lot of books and I did a lot of thinking about what I wanted to do do. And after a year, I hadn't made the progress running wise that could justify, well, that could pay for an apartment, for example. So I was like, yeah, okay, I'm 25 now, or 24 or whatever it was, I need to do something else. So at that point I ended up applying for some postdocs and I ended up taking one at the University of Maryland, sponsored by the National Security Agency in quantum computing. Again, it was sort of a hedged bets. It was like, I'll take this because the research sounds really interesting and the people are fun and it may lead to a physics career, but it sounds fun enough. And the one thing about academic life is if you choose, you can make other things like running your priority. And so I went and I trained with a very, very good training group led by a guy named Matt Centroic Sr. Whose, whose son went on to win the Olympic gold medal in the 1500 in 2016. So I spent two and a half years there in physics, kind of giving physics a shot. But also as a way of. As much as I say running was the most important thing in my life until I was 28, it was never the only thing in my life. And I also always wanted to be continuing to develop in other ways and sort of making sure that my CV wasn't going to be too empty at the inevitable point when I had to move on. So I took a postdoc at that point and went back into physics.

When you get to the end of that period of time, presumably, is that when you pivoted to journalism as the next step? And if so, I mean, how in the world did you gain the confidence to do that? Because we've established that the gradient generally points in one direction and physics might be harder than journalism, but I don't know that that's necessarily true at the individual level. Right.

And yeah, it doesn't impress anybody that you can solve the Navier Stokes equation if your job is to write an article. So it's always hard to kind of write history in retrospect because you see the patterns that you didn't see at the time. And so I'm never sure how accurately I can explain why I decided to do this, but there were a couple of things. I did have the starting of an interest in journalism. I hadn't pursued it earlier. I wasn't like doing student newspapers in college or anything, but I liked the idea of writing. And I'd actually, this is one thing that marks me as unusual, I think, is I had enjoyed writing up my PhD. Everyone else is like, oh, I love doing experiments, but I hate writing it up. I was like, man, those experiments were hard, but it's kind of fun trying to explain why I was doing what I was doing, which is very hard to explain. So I kind of thought I might like writing. And I'd written a couple of. It's a stretch to call them freelance pieces because they're basically like, I'd written a back of the magazine piece for Physics World, and I'd written a piece for Athletics magazine, which is a track magazine in Canada. And so I thought I'd like to give journalism a shot. So I applied for a bunch of internships and as you were saying, doesn't work as clearly as you might think. I didn't get any of these internships and I thought, okay, this is. My hopes of trying journalism are stalling. Do I need to sit up late at night and write articles? And prove that I can do it. And I ended up kind of deciding that it was a credentialing issue, both a credentialing issue and an urgency issue. I needed to jump into the deep end and force myself to survive as a journalist and also have some way of showing people that I wasn't just a dilettante, even though I was at the time. I needed to show them that I was serious about journalism, that I had decided to do it, and that I was going to learn the basic skills. So while I was doing my postdoc, I applied to a few different journalism schools for master's programs. And that was helped along by the fact that this was 2004 by this time, and I was timing it in such a way that it's like, well, I'm going to give one last shot to make the Olympics, and if it doesn't, Olympic trials are end of July. I'll start journalism school right after that. But what ended up happening is I got a stress fracture in my lower back three months before the Olympic trials, which meant I was out for 10 weeks. And then I did about two weeks of jogging and then went to the Olympic trials and just sort of as a farewell to running. But that made it easier because I knew that at that point, my Olympic dreams were officially over. You know, some might say they were over before they even started. But I'd been deciding that I didn't want to continue on with physics, and I was considering journalism. And then the end of running marked a natural transition for me, or at least the end of that part of my track career. I wanted something else to be passionate about, to be. To sort of pour that part of myself into. And I guess the one other story I'll relate is that I actually remember at some point that year, we were working long hours in the lab. You know, sometimes it was 12, 14 hours in the lab, and I would leave to do my runs or whatever. And I remember coming into the lab one morning, you know, after we'd been there late. We'd all been there late the night before. And one of the guys asked me, like, oh, did you see that story in Physics Today about, you know, whatever? I was like, no, no. I was in the lab for 16 hours, you know, 14 hours or whatever it was. Yesterday, I went home. I did not think about physics. I had zero interest in reading about physics when I got home. And I kind of realized, oh, wait, that's what some of these other guys do. They love it. It's their passion. And that's great, but it's not mine. And so I needed to find something or I wanted to find something that I wanted to keep doing where the work and the play overlapped a little bit. You know, I thought about things like music that I care about a lot and about running that I obviously care about a lot. And I thought, what is the possible way that I can have a chance of maybe pursuing some of these interests of mine in a professional way? And journalism seemed that. That's what I think. What pointed me to journalism is that it wouldn't be easy, but there may be a chance that I could end up writing about running or travel or music or something like that.

Now, at this point, Alex, you've obviously got tons of athletic experience as a runner. Your background in physics means there's nothing quantitatively you can understand. Had you at this point delved into the physiology of running? Or was that not yet something you had really fully explored the depths of.

Yet by the standards of. What I would say now is like, no, I didn't have a clue. I knew nothing. Now, I was the kind of guy who, when I got into running in high school, I got books about running. And you know, one of the first books I got was Tim Nose's Lore of running, which is 900 and something pages. In the first 300 pages or so are physiology. I didn't really understand the physiology when I went through it, but I was, you know, familiar with the terms. And there's some other. I'm looking over at my, my shelf right now. I can, you know, I've still got my original 1990 copy of Lore of Running right there. And there's a book called Better Training for Distance Runners, which is co. Written by a physiologist, which. So I had read all that stuff and I had this so I, I could talk about VO2 max and lactate threshold with other people who were interested in this stuff. But I wouldn't say I had a deep understanding of where it came from. I had a superficial acquaintance with the concepts.

So begins another apprenticeship, basically, which is now you're, you're getting to learn physiology as you start to write more and more about these topics.

This was not right away, I will say. I did one year of journalism school and then I had 16 months as a, as an intern at a newspaper called the Ottawa Citizen, which had a great internship program at the time. And I was covering car accidents and dog fashion shows and, you know, what have you. I learned to write. I learned to write on deadline. I wrote, you know, 250 stories or something. You mentioned being prolific. Like when you're the lowest man on the totem pole at a daily newspaper, you learn to write fast, multiple stories a day. And then my internship finished, and I became freelance, not because I had a bold vision, but because there were no jobs. And initially, my first contact through a friend was with the bottom line, which your subscription may have lapsed, but it's Canada's Accounting Monthly. So I went to some conferences on forensic accounting and stuff like that because, in a sense, I was running away from physics, and running was still a bit of a tender spot. I'd sort of poured so much into it. So I wasn't looking to necessarily immerse myself right away in these. And it's only. I would say it was about 2008. So a couple years after I finished journalism school and after I finished my newspaper internship that I started to get into writing about the science of running, to sort of bring those two interests together.

Go back to that internship at the Ottawa Citizen. I want to understand a little bit more about what you learned in journalism school as it pertained to teaching you how to write and then what you learned during that internship where you're on the ground, right? It's the rubber meeting the road, so to speak. What were the two different skill sets there? And how can somebody. I'm asking this for purely selfish reasons, by the way. How can somebody who's constantly interested in improving their writing learn from that if they're neither able to go to journalism school nor take a formal internship for a newspaper where they have an editor that's giving them feedback constantly?

Presumably what I got out of journalism school was an understanding of the. The jargon, for one thing, but also the forms. We tend to think of writing as. As a. You think of what you want to say, and then you write it down. In high school, a lot of us learned the Hamburger essay. There's five paragraphs, an introduction, then there's three main points, and there's a conclusion. And in each, you have a topic sentence in each paragraph, yada, yada, yada. So there's this really rigid structure. And what I don't think I realized until I went to journalism school is that there are underlying forms for most of the articles we read. And a news story has a very specific form. It's called the inverted pyramid, a feature article with the kind of thing you read in the New Yorker or something. It also has a certain form. Now, for good writers, that form is invisible. And that form is also played with and your expectations are dashed. Sometimes you think you know where the story is going and then it goes somewhere else. Yeah. And so on and so on. The point isn't that you need to be slavishly following those forms, but you need to understand what the forms are, so you can understand when you're deviating from them, you're doing it on purpose. And you can understand what a reader's expectation is, even if the reader himself or herself doesn't realize what that expectation is. And so there's things like, yeah, you need to have a billboard paragraph that tells the reader what to expect. Anyway, I'll just sum up by saying that I learned about form. Now, learning about form is not the same as mastering the form. And so you go to an internship at a daily paper, and actually good internships, hopefully you're getting an editor who's looking at your stuff and you're getting a little feedback. But the reality is it's a daily beast and there's not a lot of time for that. But you're writing sometimes three stories in a day, but certainly typically a story a day. You're rarely getting more than a day to write a story. And you're getting a sense from editors and from other people of what's working and what's not. And you can see what's working and what's not. And so there's the just doing it part of it. But I think that would have been harder to benefit from if I didn't have a sense of what the structures are that you're trying to transcend. You're trying to be more than just plugging in the pieces of a jigsaw puzzle. But I mean, I gave a talk on science writing a while ago to some postdocs and grad students. And the main point I wanted to get to them is that every piece of writing has form, whether it's a grant application or a scientific publication, or particularly, a lot of scientists are interested in communicating their results to a wider public. And they have to understand if they're writing for a newspaper op ed page, what is the form. I guess the other thing I said in that context is also understanding who the audience is. Those two things are interlinked. If you understand who the audience is, you understand what their expectations are in terms of what the piece is going to flow like. So anyway, what that boils down to is obviously doing lots of it, but also trying to look at the writing that you like. The stuff that if you see a book or an article that you like, or that explains things clearly trying to break down, like, so what are they doing here? What makes this work? Did they have a particularly good introduction section or whatever the case may be? So reading critically, I guess, is what I'm saying.

I almost wonder if it's somewhat like athletes, where you could have the same debate about good writers being born versus made in terms of scientific writers. I think Sid Mukherjee is incredible, and I read his stuff, and it's no different than watching a remarkable athlete do something and you sort of think to yourself, there's probably no way ever that I could write like that, even if I devoted every waking moment of my remaining life to this study, any more than I could swim or bike or run as well as the most amazing athlete I see doing those things. Do you think that there's a parallel there?

I think there's a parallel, and I would extend the parallel, which is that we can look at Michael Phelps swimming and say, I will never be able to swim like that, but it's a mistake to then say, swimming is all genetic, and therefore I am doomed not to get better at swimming than I am right now. And most people don't come anywhere close to fulfilling their quote unquote, genetic potential. So, for sure, and especially when I read fiction or when I read nonfiction by good fiction writers who know how to write nonfiction, that's not to get too confusing, the level of language and imagery, to be honest, it's sometimes a little depressing to me because I feel the same as you. I'm like, yeah, there's no amount of workshops or practice that it will make me write like that. And so I think another thing is just to maybe this is too defeatist, but own who you are. And so I know that for me, I'm not a poetic writer, but what I hope to be is a very clear, expository and explanatory writer. So I will never paint the picture that I really admire in some other writer's writing, but hopefully I can excel at another aspect of it.

Yeah, no, that's actually a great way to compare the two. So with that, let's just start with sort of something you've already alluded to. Let's explain what it is, talk about how much it matters, and then kind of get into some examples. So let's start with a term that many people have heard before, but I don't think most people understand what VO2 max really means. And eventually we're going to talk about running efficiency and lactate threshold, and we're going to get into all this stuff. But let's make sure people understand what VO2 max is, both in an absolute term and then in a manner that we normalize it by weight and what it is and what it isn't, how it's measured, how it matters, and maybe we'll even talk about some notable exceptions.

So VO2 max is the one physiological parameter that anyone who's involved in endurance has heard of and has some sense of. The first order analogy is it's kind of the size of your engine. Physiologically, VO2 Max is telling you how quickly you can take oxygen from the air into your lungs, get it into your blood, pump it to your muscles, and then have your muscles use it in the metabolic processes that will provide energy to move you to do whatever you want to do. So it's a rate. It's how much oxygen per unit time can you process? Absolutely, flat out. Now, the sort of backstory here is it was first sort of discussed or measured in the 1920s by a guy named A.V. hill, who was actually a very good runner. The observation that he made is if you have someone, you ask someone to go out and run at a gentle pace, they'll consume, let's say, two liters of oxygen per minute. Then you tell them to speed up. Now they're doing 3 liters of oxygen per minute. Tell them to speed up again. And now they're going pretty much maybe not as fast as they can, but they're going fast. And they're losing 4 liters of oxygen per minute. So you tell them to speed up again, and you measure it and they're like, oh, they're only using 4 liters of oxygen a minute, just like last time. Speed up again, and they're still just using 4 liters of oxygen a minute. There's a plateau. There's a point at which, even though you're working harder, you're not using any more oxygen. And so this plateau looks like it's a physiological limitation, and it probably is in some sense. You know, it's a controversial thing, but basically you've reached a point where no matter how hard you push yourself, you can't get more oxygen. And so you can still go faster because you're starting to use other forms of energy.

But.

But this is the limits of your aerobic system. This tells you what it tells you we can get into. It's not clear what it tells you. It tells you exactly what I just said. It tells you how much. How much oxygen you can use. Does that tell you exactly how fast you can run? No, there are a lot of other factors, but it's. That tells you what sort of aerobic engine you have to play with.

I remember in high school, I mean, we would sort of talk about, well, which athletes have the highest VO2 max? Is it the Norwegian cross country skiers is the professional runners and cyclists and things like that. But the people are usually used to hearing these numbers reported not in liters per minute, but in milliliters per minute per kilogram. So give an example so people understand those differences, because we usually talk about the outliers as a number. That's a bigger number than 2 liters or 5 liters. It would be sort of 75, 80 milliliters per. Just explain to people how those are different.

Sure. So I'll use my own numbers. Typically when I was tested, I could get about a little bit more than 5 liters per minute. So 5.1, 5.2, if I remember correctly. Now, if you compared me to a rower, the rower would make me look pathetic because the rower would be using 7 liters a minute or more. But the rower is also huge, twice my size or whatever. And so that doesn't necessarily mean that that rower is better at using oxygen for me, because the rower has way more muscle. And so the rower is. The amount of oxygen reaching any given muscle cell may be lower. So if you want to compare apples to apples between athletes of different sizes, you divide, at least for a crude approximation, you just divide by weight. And so the numbers we usually hear are rather than liters of oxygen per minute, it's milliliters of oxygen per minute per kilogram of body weight. So for me, five liters of oxygen per minute works out to something like 80 milliliters of oxygen per minute per kilogram of body weight. There's a whole rabbit hole to go into is to say, well, why are we dividing by whole body weight? Because, you know, there's a bunch of things like skeleton and organs and stuff that don't scale.

The adipose tissue doesn't matter. I mean, you could argue a better comparison would be total liters per minute divided by lean mass divided by time or normalized to time. And then you're at least getting the metabolically active tissue, presumably.

Yeah. And there's papers where they do things like let's divide by weight to the power of 0.68 or 0.7, which is another way of getting effectively, it's a way of approximating just the lean mass, the metabolically active tissue. And you can go down that rabbit hole, but I suspect you'll want to get to is. It's like at a certain point, it doesn't matter that much anyway, so we don't need to. You can't just measure someone's VO2 max and know how fast they're going to race. So it's useful, but it's not especially for comparing between people. Now, comparing within yourself, it tells you something if you've increased or if your VO2 max has decreased. But in that sense, it doesn't matter what you're dividing by.

I remember there was a guy that I used to ride with, and this was not that long ago, maybe five or six years ago, when I was still, you know, somewhat competitive, at least with myself, actually. It's funny, my number was just like yours, except I was heavier, so I was about 5.1 to 5.2 liters, but I weighed more, so that worked out to about 70 mils per milligram per kilogram was my VO2 max. His was 55 to 60. But there was never a day that I could ride faster than him. Not one. There's simply. And I always felt like, although we did the test so many times, I kept feeling like the machine must have been broken on him. Like, I knew my 70 was about right because I'd been tested so much, and that was lower than it had been when I was younger, so it seemed appropriate. But I was always convinced that there's no way he's only 55. The reality of it is, he may well have been, and he may have simply been a far more efficient athlete, which we're going to get into. Before we get to the story of Oskar Svensson, let's talk a little bit about historically, what people have believed the limits are of VO2 max.

We don't even have to go very far historically to get into a whole mudslide of confusion and debate and disagreement. There's a lot of places along the way that could, in some circumstances, be the bottleneck. Normally, people tend to assume that what is it that causes VO2 max to plateau is essentially, I think, what we're talking about. And just one thing I should add here. It's like, why is that interesting? It's because you think, well, if you want to measure endurance, just have someone run a mile or whatever, as hard as they can. But any test like that depends on motivation, depends on whether you pace it right. There's all these factors that come into it. The nice thing about VO2 max is that in theory, it's Independent of motivation. That's why scientists like it, because it doesn't matter if the subject doesn't really care about the study. If you see a plateau, you know, that's a property of their body and not a product of whether they were excited about the study. So the question is, this plateau, what is it that causes it? And it could be in the lungs, it could be the heart, it could be the circulation, it could be the muscle's ability to extract it. I don't want to pretend that I know the answer because it's still controversial. The picture that emerges is that almost every part along this cascade is engineered more or less to what it needs to be. And so if you perturb any of those elements, you can get limitations. So, for example, the conventional wisdom is that your lungs are not a limitation. You can always breathe enough in. And so then the question is, can you diffuse enough oxygen from your lungs into your bloodstream? And so on and so forth. There are situations where, and it's been for decades, it's been conventional wisdom that the lungs don't respond to training because they're overbuilt. There was just a paper published, a big review in the last month or two arguing that, you know, in some cases, the lungs aren't overbuilt. And one of the situations is highly trained endurance athletes. They can be limited by their ability to get enough oxygen in. And you can also run into situations where an athlete is so fit, their heart is so strong, it pumps blood past your lungs so quickly that it doesn't have time to fully stock up on oxygen. You get something called exercise induced arterial hypoxemia. So this. This is usually an issue at altitude, but in elite endurance athletes is actually about half of them exhibited even at sea level. So they're already running into a limitation just in getting oxygen from their lungs to their body bloodstream. And that at every stage of the way, there can be limitations if anything is knocked off kilter, and certainly right down to the ability of the muscles to first extract the oxygen from the bloodstream and then to make use of it metabolically in the mitochondria. So there isn't one single answer, which is why you get these debates, because everyone is, I have evidence that this is the limit. It's like, yeah, but I have evidence that this is the limit, and that's the limit. And they're all the limit.

Yeah. I've always wanted to see the experiment where you took a group of athletes and maybe this has been done. You run them all to max. And then you reduce the FiO2 of the incoming oxygen. So normally we do it with room air. So you're getting the fractional inhalation of oxygen is 21%. And the way, of course, just for the listener, the way these things work is the way they're calculating how much oxygen is being consumed is they're measuring the concentration of oxygen on the way out. So you're calculating the delta. And so I've always thought, well, wouldn't it be interesting to start selectively dropping FIO2 21%, 20%, 19%, 18%. Now, presumably, if the lungs aren't the limitation, you should still see the same absolute delta. And you could at least start to eliminate one of those variables, which would be FIO2 and capillary exchange. And then you start pointing to some of these other variables. Again, I'm sure somebody has done this experiment, but I don't know what it yielded.

Probably not with the fine tooth comb that you're suggesting. People have compared 21% to 10% or whatever, and 15%. I mean, it's interesting. When you go to altitude or the equivalent, when you reduce the amount of oxygen, funny things happen. The first thing you would think would happen is you can't get enough oxygen, so you're going to go anaerobic sooner, you're going to produce more lactate. And yet the opposite happens. There's something called the lactate paradox. If you try and exercise to exhaustion at lower levels of altitude, you actually give up when your lactate levels are lower than you would at sea level. And there's debate about what causes this and even whether it's a real thing. But the picture that makes sense to me is, is that these things are not just about how much oxygen is making it to the muscle. It's also like, what is your brain oxygen level? And so you're. You're getting these other circuit breakers that are starting to come down that aren't even on this path from mouth to lungs to blood to muscle. There's other factors that are saying, whoa, wait a second, oxygen's getting a little low, so we're going to actually cut off the supply to the muscles or reduce it in order to make sure that we don't get stupid.

Prior to Oscar, because I want to talk about this kid, his story is so interesting, and you wrote a great article about it, and I've read many articles about him, including articles in physiologic journals. You'd had a couple sort of freaks of nature out there. In the 90s, right. So 90 plus milliliters per kilogram per minute of VO2 max. What happens in sort of a garden Variety Day of December 2012? Do you remember when this. When he shows up to a training lab? He's what. How old is he? He's like 17.

17, I think he was, he was a former downhill skier who had taken like a talent screen to see whether he'd be suitable for something like cycling. And he'd. I think he'd scored just untrained, just off, off the downhill slopes. He was 74 or something like that, 74 milliliters per kilogram per minute. So that he passed. And so they started training as a cyclist as a teenager and pretty quickly scored 83, then 85, then 92. The initial reports were that he scored 97.5, but I think when the scientific journal came out, they said it was.

96.7, which either way was still higher than had ever been recorded in human history.

And one thing we should say is there are reports of people in their 90s, but reports high VO2 max numbers, they sprout very easily because it's hard to do these tests. Right? And in fact, a lot of the tests that people, the garden variety machinery used to do these tests is not designed to handle 7 liters of oxygen per minute. And so you get spurious results and you get. So the previous king was a guy named Bjorn Dali, the greatest cross country skier in history, who in the late 90s, reputedly tested 96, 96.0 or 96.6, depending on who you ask. This was never published in a journal. This was basically the Norwegian ski team leaked it to the press as a kind of PR move. And I asked a guy who was working in Norway at the time and he said they didn't believe the machine. He didn't believe the machine was correctly calibrated, but he figured they decided that it was a good PR move anyway. So when we're talking about high numbers and there's Matt Carpenter, 92, Kelly and Journey, there's a lot of people who have high numbers. Virtually none of them are published in the scientific literature. The highest values, you go back to the 70s where some of the great runners were tested and you get Steve Prefontaine was 84, and there aren't a lot of published values above the high 80s. So 96.7 is like, it's higher than the rumors, but it's way higher than the verified numbers. So the first thing they did the next day is they disassembled the machine, the metabolic cart, and sent it back to the manufacturer to get it calibrated to find out if they, you know, are we nuts? Is this real? Is this true? And it came back that, yeah, it's working. And all the other tests done that day.

Yeah, exactly. All the other tests that were done in that day were all within line.

Yeah. So they figured this is real. And so they eventually, I mean, the story is longer. After his retirement, they published the data and shared it, which was pretty cool.

Well, I think the other thing that was very compelling was he was tested again several months later. He put on two and a half kilos. So his number came down into the 80s, but his absolute level of maximal oxygen consumption had barely come down. He went from something like 7.2 liters to 7.1 liters, but the number came down from, call it whatever it was, 96 and change to 89 and change which was accounted for by the gain in weight, which again, is effectively like repeating the test and getting the same result.

I agree. To me, that's actually the number one piece of data is that off season test a few months later, later in that year, it's like, okay, well, if he's doing the same amount of oxygen, we understand that people can put on weight and lose weight, but the absolute value of 7.2 or whatever suggests that this was a real number. And the other thing to say is at 17, or whatever it was after he clocked that 96, a couple of weeks later, he goes to the World Junior Championships and wins the time trial there. So on the surface, it's like, that goes to show if you have a big engine, you're going to be a superstar.

But of course, the flip side of that, and the reason I brought this up, was to say, why do most people listening to this, who might even be able to recognize the best time trialists in the world, the Bradley Wiggins of the world, no longer active, but the people who go on to win grand tours and stuff. Why don't we know this guy's name?

Yeah, so he turned pro when he turned 20. He was with an under 23 team called Joker. He was an okay cyclist. He had some good results, he had some bad results. I think it probably didn't help that he got a lot of attention for this VO2 max value. So I think the expectations were probably out of line with what was reasonable, both from his own expectations and other people's. And he ended up retiring. I think he was 23. Maybe he took a break and then he officially announced his retirement. Retirement when he was around 23. Went back to university and he's done, he's gone. So the aftermath was that there was a paper published, I don't know, I think it was about a year ago, that sort of reanalyzed or responded to when they published his data and said, well, let's look at not just his history of VO2 max values, let's look at his efficiency at each point along the line. So over the course of three years, or whatever it was, where he had multiple VO2 max tests and you see this expected pattern, he starts at 74 and he goes 80 something, 80 something, 90 something, 96. And then he comes back down the ladder. By the time after he retired from cycling, he was back down to 77. So he's right back where he started. That's a simple story. But if you look at the efficiency, you get a much more interesting story, which is that he started out at his most efficient when he was untrained. And the more he trained, the less efficient he got. Meaning that he could deliver more oxygen to his muscles, he could deliver more aerobic energy, but. But he used more aerobic energy in order to maintain a given pace.

Let's make sure folks understand how that's calculated. So now you look at a different graph where on the x axis you show wattage, which is the universal metric of output in cycling, and on the y axis you show oxygen consumption. And so now you're looking at a graph that says for a given output, how much oxygen, how much input do you need to get this output? And an athlete over time should get better and better. For a fixed wattage, you want to see what's called PVO2 come down. So power at a given VO2 should actually come down as you get better. In running, this would be the VVO2, you want to get faster. So for a given oxygen consumption, you want velocity to go up just as you would want power to go up. I might have said it backwards earlier, but I think you know what I'm saying. So I got to be honest with you, I was actually very surprised by that. I would have been less surprised if it had been unchanged, but I was very surprised that it deteriorated.

Yeah. And there's lots of debates about whether you can improve it, but to actually see it get worse was so clearly and so kind of monotonically, there was an inverse relationship was definitely surprising. And it actually plays into a long standing debate, which is the question of is there an inverse relationship between VO2 max and efficiency. So if you build your engine bigger, do you necessarily end up with a less efficient engine? And this debate's been going on for a couple of decades now and there's still no consensus. And one. So one way of if you just take a bunch of elite athletes and you measure their economy, whether it's runners or cyclists, and you measure their VO2 max, you tend to see an inverse relationship. The people who have the highest VO2 max tend to have slightly lower, slightly worse economies, and the people who have the best economy tend to have slightly worse VO2 max. There's a lot of possible explanations for this. One is that you don't tend to hit the lottery twice. So if you happen to have a VO2 max that's 92, then you're not that lucky. You're not going to have the best possible economy. And if you're only looking at elite athletes, that means that everyone else there is going to have something special. So if they don't have the best VO2 max, by definition they have to have a great economy because they have to have something that's exceptional. And so you see this inverse relationship that either you have good economy or you have good VO2 max.

And just to be clear, that's because we've selected for people whose dot product of those two things is the best in the world.

Yeah, if you're looking at elite athletes, they have to have won at least one lottery, but they're unlikely to win two lotteries because we're already looking at the 0.001%. So it's highly unlikely that you're going to have hit the lottery twice. But so what the Oscar Svensson data points to is a different explanation, which is that there's actually a trade off, that if you're optimizing one physiological parameter, it may come at the cost of the other physiological parameter, that the training he did, which we can sort of surmise, must have been pretty good for increasing VO2 max because he got such a high one, may have actually been bad for his economy. Not in the sense that his legs were wobbling or he had bad motion, but at a metabolic level. And there was a paper published again in response to the Svensson case study, reanalyzing his data and pointing to a potential cell level explanation of what's happening to certain enzymes at a given point. The biochemistry, frankly, is beyond me to fully understand, but basically what they're saying is if you're doing a lot of training that requires very high, like VO2 max level outputs, your metabolism, your cells need to make choices to produce high output instead of to be as efficient as possible. And over time, that's what you'll get better at and you'll lose that efficiency. And so you'll pay a slight penalty for optimizing your training for VO2 max.

Yeah, so that was kind of my take, which was not knowing more about his training, was what would happen if you took that engine, if you took that, that genetic gift. And instead of maximizing on VO2 max and pushing him from, I mean, a guy that gets out of bed in the morning or falls off a log at 74 is a freak of nature. But instead of pushing him to 96, you train him and he'd get up to 85 or 90 maybe, but you put much more effort into sort of zone 2, where you're right at lactate of 2, so you push him. And by the way, for him that would be like if you looked, I remember looking in the paper in Applied Physiology. I mean, you know, he's spending a lot of time in the 3 to 400 watt range, but he could have probably been in the sort of 300 to about the 300 watt range, where he's still just under 2 millimole of lactate. But he's dramatically increasing mitochondrial efficiency. And if that represented 2/3 of his volume, yes, he'd have a lower VO2 max. But he might have been a better cyclist.

Certainly putting on the hindsight spectacles, I 100% agree. Whatever he did, he paid too high a price for that VO2 max. Just by definition, it didn't work out. And again, we don't know exactly what his training was, but that makes a lot of sense to me and I think it sort of agrees. And you've talked a lot about this, but with the sort of prevailing wisdom among endurance athletes is that, yeah, you know, 80% of your training should be easy conversational pace. And what means you use to figure out what pace that is may vary. But he needed to be doing something that was going to at worst not penalize his efficiency as much as he did.

I just remember even as an adult, whenever I wanted to go and have a VO2 max test just for ego, you wanted it to be as high as it could. I would alter my training for four weeks and lose a couple kilos. It's lose two kilos and start doing four to six minute all out intervals. That was the recipe for raising VO2 max. So abandon all low end and it's 4 minutes all out, 6 minutes mild. But those are killing workouts. Those really crush you. So yeah, there was just like kind of a formula to make it happen. So let's pivot now and talk about something you've also written about that I find completely amazing from a physiologic standpoint, which is the sub two attempts and the incredible effort of Kipchoge. So I don't even know where to begin this story. But again, let's just assume for a moment that listeners aren't familiar with who Kipchoge is, aren't even familiar with the difference between an official marathon versus a contrived Nike marathon. Start from the beginning.

Okay, so the very beginning. I'll give you the medium long version of the story. The very beginning is that in 2014 I wrote an article for Runner's World that was about 10 pages long. I spent months on it analyzing the prospects for a sub two hour marathon and talking to a bunch of experts, crunching data, blah, blah, blah, what would it take? And at the end of that article, my prediction was that it would be physiologically possible to run a sub two hour marathon and that it would happen sometime around 2075. So that was my context and I'll take ownership of the prediction, but the general sense was that yeah, it's possible, but it's not going to happen for a long time.

And just to be clear, Alex, what was the world record at the time and did your prediction speak to an official marathon or any form of marathon?

Yeah, yeah. So I was thinking about marathons as they are currently run. Although in my article what I said is, look, if it's going to happen, it's going to happen on an optimized course. You're not just going to go to any old course, so you're going to choose a course that optimizes temperature, it optimizes terrain, it optimizes curvature. So there's a lot of things you knew right away, the way marathons were run and mostly continued to be run. There's fat on the bone in a way that there isn't in sports like track or if you look at the Tour de France, there's fat on the bone, but no one cares about the time compared to track cycling, where everything is optimized. So marathons are this kind of anomaly where they're run in a Tour de France style in a very uncontrolled environment, which differs from from race to race. And yet we care about time. And I think that's maybe an anachronism that's going to fade away a little bit as we realize that, you know, you can, you can run a lot faster if you optimize the course. But anyway, to answer your question, the world record was 20257 by a guy named Dennis Cometo. So we're talking three minutes away from a sub 2. If you say how long did it take us to come down? Three minutes. Well, in the mid-80s, I think it was 1986. The world record was 2 hours and 50 seconds. Bible I need in simul. So we're talking timescale 86, 90.

Yeah. Call it 30 years to go. Four minutes.

Yeah, exactly. And of course things are getting optimized as we go. So you expect the curve to be leveling out. There's less and less low hanging fruit to get. So in 2016 I got an assignment from Runner's World to go report on this top secret Nike project. It was something they called Breaking2. It's a race they held in spring of 2017. And their mission was basically they'd spend about two or three years, 20 people full time working on it, trying to engineer a sub two hour marathon. And so they started with a huge talent search. They sponsor a large fraction of the world's best runners. So they brought 20 something of their best runners to labs to measure their VO2 max and their economy and various other things and picked three runners and then they went around the world world testing possible courses. They ended up settling on a Formula one racetrack in northern Italy.

Yeah, it was Monza.

It was, yeah. Which I think is where the highest speed ever reached on a single lap is there.

I'm obsessed with Formula one. So if you're interested, Monza is the fastest Formula one circuit. You don't look at the maximum speed, you look at the fastest average speed. So Monza has the fastest average speed of any Formula one circuit. There are other characteristics that make Formula one circuits interesting. Which have the highest G forces, which have the highest straightaway speeds, those things. But yeah, Monza has the fastest, highest average speed and of course doesn't have much elevation change, which is probably even more important. Right?

Yeah. So they used the junior loop, I think it was called at Monza. So not the full one because that was the straightest possible with just the barely perceptible curves. I think it was about a mile and a half loop or something like that. Also it doesn't have much elevation change. It's. It's close to sea level, but it's not close to the sea, which makes the Weather a little more predictable. They optimized a lot of different things. You know, they're trying to optimize the nutrition, the in race nutrition, the aerodynamics. They're like doing things like sticking adhesive bumps onto the legs of the runners to try and reduce the drag. When they're swinging their legs back and forth, some of it's a little ridiculous. Some of it was significant. The two significant things were they were going to have five or seven pacemakers basically blocking the wind for the chosen runners for the whole way. Now you can't hire someone to run a sub two hour marathon in order to run a sub two hour marathon. So they had to have runners dropping out every couple laps and new runners swapping in. That's not allowed according to the official rules of marathoning. So that's the main reason that this race that Nike had planned was not and is not considered a world record, because it doesn't obey those rules. And then the other, the other factor, the big factor is they introduced a whole new type of shoe that had a curved carbon fiber plate embedded in the sole that improves running economy. In other words, it allows you to burn less energy to sustain a given pace by about 4% on average. So put all these things together and all of a sudden it's like we don't actually need the runners to be that much faster than 20257. If all these things we've come up with work, we should be able to slice three minutes off the time with the shoes and the drafting and the course and the weather and all these sorts of things. Of the three runners they ended up selecting, Eliud Kipchoge was the reigning Olympic champion. And he was also probably the most consistent and the best marathoner in the world at that time. He was, I think he had the second or third fastest time in history at that point. And then they had a couple other guys who had good lab values. One of them had the best running efficiency ever measured. But neither of those guys ended up being a factor. Kipchoge ended up running two flat 25 at this Nike breaking two race. So two and a half minutes faster than the world record. Didn't run sub two. But that was considered a victory because it was like nobody thought anyone would. Even with all the sort of science and tech, nobody thought that it would actually add up to a human running that fast. So then there was a sequel in, in 2019, funded by the petrochemical company Ineos instead of Nike in Vienna, which basically replicated most of what Breaking2 had done. They only brought Kipchoge in. They had a few different things. They had a new pair of shoes which became very, very controversial. And this time Kipchoge ran 159.40. So he ran a sub 2 marathon. And it has galvanized and polarized the running world because Kipchoge is the greatest marathoner in history, I would say. But these events left a bad taste in the mouths of a lot of people, both for their the sort of circus like quality, but also because of the shoes. The shoes became very controversial because it's not clear whether shoes that make you 4% more efficient with a carbon fiber plate embedded in them are within the spirit of the sport or within the rules of the sport.

I mean, this sounds an awful lot like where swimming was in 2008 and 2009, when the tech suits from basically 2000 to 2008 had gotten so quick that by 2009 FINA said, this World Championships in 09 will be the last time there are technical suits. And away they went. And actually there are still some world records that stand nearly 12 years later from those 2009. Yeah.

The surprising thing to me is that not all of them stand because at the time I remember interviewing some swimmers and saying, so do you think you will never again set a personal best? There was this sense that banning those suits would just completely change the record book. But it has turned out that swimming has continued to advance. I guess there's advances in pool technology and stuff like that, but yeah, it's exactly analogous debate. What role should the equipment play in a sport that is not like Formula one, whose inherent attraction is its simplicity?

But to play devil's advocate, right? I mean, would the current running shoes you would wear if you were to go out and run a marathon, or would they offer a 4% efficiency over leather you would strap to your feet?

It's a good question. I think they would raise my chance of getting to the finish without injuring myself, because cushioning is the big advance. The more sort of pointed analogy is cinder tracks were common until the 60s. Then you have all weather tracks. I mean, it's apples to pears or whatever.

Or look at cycling, right? I mean, consider a bicycle today versus a bicycle 20 years ago, not 100 years ago. Just look. I mean, if you look at the bikes ridden in the late 90s versus today, they're not even the same thing. They're not even close.

Well, the hour record is such a classic example of that, because cycling did try and say you know what? Let's make it about the cyclists, not the cyclists. We're going to all ride the 1972 Eddy Merckx Special for the hour record. And the response to the cycling world was like, okay, we're not interested in the hour record anymore. Forget about it. It's uninteresting to us to go ride this stupid 1972 bike. And until they change the rules again in whatever it was, 2015 or something, and all of a sudden everyone's like, hey, all right, now we're interested in. So the key that I would say in agreeing with you is that anyone who thinks that the progress of the sport over the last 10 years, much less 50 years, much less 100 years, is all about, well, we've learned more and we're digging deeper, is kidding themselves. Technology is baked into the improvement curve. Changes in circumstances, environment and technology are baked into those curves right from the get go. Now, you can acknowledge that and still say, I understand the curve's going like this, but I don't want it to go to drop off a cliff. And the world records have been absolutely knocked silly in the last two years since these shoes have become common. I still think it's, you know, I think it was a tough call. I don't think it was obvious that you could ban them until they'd already been used enough to realize that, oh, wait, this is real, this is a big advantage. By which time it was kind of too late to ban them. Because the thing is, I mean, as a guy who follows this stuff relatively closely, I'm used to press releases every year, if not every day, that promise to upend the sport. And this is going to be the newest, greatest, latest, best thing. It's, you know, so you ignore that stuff. And so even if Nike had said, hey, by the way, just a heads up to world athletics, we've got these shoes and they're crazy. Is it okay that we introduce them? And all the ingredients of the shoes are things that had been used before. So there was nothing like. There was no, like, coiled spring in it. Carbon fiber plates had been used before, including to set world records. So there was nothing. It's just Nike got the recipe right. They got it so right that it changed the sport. And it, in the long run, things will settle back into parody and we won't worry about it. But there is a period about 2016 to 2019 where it's like, if you didn't have the right shoes, you probably weren't going to win the race. And that is A little unfortunate.

Where do you think this all fits into your prediction? Whatever year that was, 2014. I mean, when do you think two hours will be broken on a legitimate road course with full marathon rules that will constitute a world record. So that means it also has to be a marathon that ends and starts in the same place. It can't be be a one and done downhill like Boston or something like that. Do you revise your estimate of whatever year you gave?

Oh, yeah, for sure. No, it's not going to be 2075, which coincidentally was going to be my 100th birthday. So maybe that was subconsciously influencing me. But the answer depends on what you define as legit. So is there something illegitimate about holding a marathon on a loop course? I don't see it. I mean, marathons, they were a big deal in Madison Square Garden back in the late 1800s. There's nothing inherent about saying you shouldn't run it in a circle. Yes, we love the big city marathon experience and it brings the people together, yada yada yada. But if you're trying to break the two hour marathon, the goal is not to, you know, be inclusive. So there's things like that. Here's another thing they did. They said we don't have a start time. We're not starting Saturday at 7am we're starting sometime between Friday at 7am and Sunday at 7am or whatever. And we're going to look at the weather forecast and we're going to make a call the day before, like 12 hours before so we can get the absolute optimal weather. Is that cheating or is that smart? Having a launch window? So there's a lot of things like that. The key thing I think is two key things. One is pacemaking. You can't have people jumping in halfway. That's the number one thing. They have to change for me to consider it like a legit sub two hour marathon. So you're going to have to attract like the second best runners in the world to go and to have them work together so that you know, one group is leading through halfway and then the, the second group is going to lead to 30k or something and then they're going to drop out and the chosen runners do it alone. So you're gonna have to optimize that. To do that you're going to need a ton of money and more generally you're going to need a ton of money to put on event. I would estimate Nike spent tens of millions of dollars on its Breaking2 race. So my 2075 prediction did not bake any of that stuff into it. But now that we've had a sub 2 and now that the official world record is 2 hours, 1 minute and 39 seconds, if I'm remembering correctly, we're within shouting distance of the two hour. I think some of those other factors may come together that someone tries to put together a breaking two style race that still falls within the bounds of legitimate. So I would say that could happen anytime in the next 10 years. When's it going to happen? Just like it's a race, we showed up to Berlin or Boston or New York or whatever and someone happens to run sub two. I think that's still a long way away because again, the progress has not been in humanity. The progress has been in understanding where the fat on the bone is and cutting that away systematically.

So if you take away all technology, what is the difference between Roger Bannister and the fastest miler today? Again, get rid of shoes, get rid of all of that. As a species, we have not evolved. So how much of that difference is technology? How much of it is training, nutrition, everything else you'd bake into it. I mean, what would be the buckets you would classify as the improvements? And what is the. I don't even know what the mile record is today.

Mile record's 343, so it's come down 16 seconds. So for Bannister to today, the biggest bucket, bar none, is training. Bannister is reputedly an under reporter. There was this sort of horrible whiff of amateurism where, you know, admitting you were training too hard was not done. But even if you take with a grain of salt his reports, you know, it was sort of half an hour a day. Go out and do 10 by 400 meters. So we're talking like four or five miles a day, five, six days a week, maybe he was doing more than that sometimes, but he was training at a level, a very, very light level. And even one of his contemporaries was Emil Zatopek, who was a, a Czech runner who.

Just a legend.

Yeah, absolutely. Like arguably the greatest distance runner ever.

Yeah, yeah, exactly.

He was starting to push the boundaries of how hard you could train. He was a guy who was going out and doing 60 by 400 instead of 10 by 400. And so it's not like nobody understood that training worked. But Bannister versus today, it's training is the difference. Cinders, maybe a second a lap, like the track quality, the quality of the spikes, negligible. And nutrition for a mile, it's not just not that big a deal for a four minute race. If you fast forward to the 60s, by the 60s you've got people like Jim Ryan who ran 351 for the mile as a teenager. He's training like a beast most people could not handle. Even modern milers would not dare to train as hard as he trained.

What did he do?

So Roger Bannister was 10 by 400 meters. Emile Zatipek was 60 by 400 meters. But they were mostly really slow. It was like another form of endurance. Jim Ryan was 40 by 400 meters. But they were all hard. They were all close to as hard as Bannister was doing.

On what recovery?

I don't want to claim that I remember, but we're talking like one to two minutes probably or a 400 meter jog and lots of intervals of. He was, it was a very interval based program. But hard, really, really hard.

And what would he run those four hundreds in? Like how many of them would be sub 60 seconds? All of them?

No, not sub 60. He'd probably be doing those in like 66, 64. Yeah. I don't know the exact times, but it's at that volume. In the context of high mileage, he was doing them at a pace that was extremely challenging. Not the sort of Zatopek style of just kind of let's get tough and not worry about the pace. Zatopek's the guy who's like in the laundry tub, just doing high knees in the laundry tub or holding his breath between phone poles on his run. So he was all about just making stuff hard, whereas Ryan was taking that to a systematic level. We're going to train hard, but we're going to do it systematically. With, with his coach, Bobby Timmons, I'd say you can't make much distinction between the training of the 1960s and the training of today. There were people who were training probably as hard in the 60s. And if you take Jim Ryan's mile 3:51 cinders, subtract 4 seconds, 3:47, the American record's 346.8 or something like that. So by the 60s, training was mature and all the other stuff that we worry about, all the nutritional aids and pneumatic compression devices and ice baths and stuff. I'm not saying it doesn't help on an individual basis, but you can't see it in the record curves or anything like that. Those things don't show up. Those don't leave a mark in the big statistical picture.

Do you ever follow horse racing at all? Do you ever follow the times that horses run and things like that?

That's exactly the comparison I was thinking of, which is that they've stagnated since the 50s, right?

Well, I mean, Secretariat is hands down the fastest horse that's ever run. And I read a very interesting argument on, oh, I don't know, it was probably on Nate Silver's365 a few years ago. That actually made the point that we're getting further from Secretariat now because we're actually seeing less diverse breeding of horses. So you're just bringing less genes to the gene pool. And of course Secretariat's genes were pretty unique, right? It was an X linked, so it was a sex linked X chromosome gift that he had genetically. That's why his male offspring didn't do anything special. But his female offsprings that would go on to pass X chromosomes to males a generation later actually were somewhat special. But Secretariats times were unbelievable. I mean, when you think about it through the lens of even running, to run a mile and a quarter and to negative split by mile, all five miles, Secretariat's winning times at Belmont, I don't think any horse will come close to that.

It's important to note that whatever amount of money we have in the running world that is allowing us to optimize nutrition and training, and yet there's way more running in horse racing. Like if there were physiological advantages that allowed us to run faster, they would be using those on horses. So like the post training massage or whatever, if that helped horses, they'd be getting it, or they probably are.

So going back to kind of your experience, let's bring it back to this idea of what you're now learning about endurance as you are back as a journalist now and you're fully ready to go back and visit your running roots in the research for your book. What are you learning about your experience on a rainy night in Quebec? And how are you able to put that in the context of what the limits of endurance are?

So I guess the start would be maybe to pick up the thread even a little earlier is I finally started to write about running and I was doing it in a very conventional way, the sort of what heart rate should you do your tempo run at and things like that. What it meant is that I was starting to look at the literature and reading some papers and I came across a paper and again, maybe 2007, 2008, it was a debate and I think it was in the Journal of Physiology and the topic of the debate was does dehydration impair endurance performance. I just remember being like, what is this? Like, April Fools? Of course, dehydration impairs endurance performance. And it was a pro and con. And the con was Tim Noakes arguing, who's a very notable contrarian scientist, let's say, from the University of Cape Town. And he was arguing that, no, we have not shown that dehydration itself impairs performance, thirst impairs performance if you're thirsty, but if you drink enough that you're not thirsty, and even if you're dehydrated, even if you've lost a bunch of weight, that doesn't impair performance. And he went through all the literature, all the famous studies that show dehydration impairs performance going back to the Second World War. And you look and it's like, well, they were all thirsty. They were all, like, stuck in a sauna and not allowed to drink. So we don't. Anyway, all of which is to say, all of a sudden I was like, oh, wait. One of the things that I thought was beyond debate is debatable. And so I started reading a little more and following this thread, and I discovered that Tim Noakes had proposed this idea called the Central Governor Model, which was, in a nutshell, it's that when you run as hard as you can, or exercise in other forms as hard as you can, the reason you stop or the reason you slow down or the reason you aren't able to go faster is not because your legs aren't capable of going faster. It's because your brain is protecting you. It's sort of putting on the brakes before you push so hard that your heart runs out of oxygen or whatever the case may be. And this was highly controversial. It was a fringe theory at the time. But that's when I started to make the connection to my race in Quebec, my 1500 breakthrough, and the whole career of why do I have a good race one week and a bad race the next week? Even when the physically there's nothing different? Like, why does it feel like sometimes I'm able to dig deeper if it's just multiply your VO2 max by your running economy, divide by your lactate threshold or whatever, there shouldn't be any change. These things don't change from week to week. And so that got me interested in the role of the brain. Now, the central. I should let me just jump ahead and say the Central Governor Model. People don't really talk about that anymore. It was a model that emphasized the importance of the brain in Understanding the limits of endurance, which has then led to a whole bunch of further research, which is what captivated me because it's like nobody needed Another article on VO2 max is about is oxygen or whatever. Although I shouldn't say that because I've written a few articles about VO2 max, but. But what struck me as interesting and what Even in by 2009, I was like, this is a. This should be a book about this that tries to explain this to all the people like me who I know are interested in this stuff, but haven't. Don't realize that there's this debate going on in the literature about how do we bring the brain in, not just in a sense of like, you have to really want it, try really hard, but to understand how the brain is influencing or controlling or playing a part in determining the limits of endurance.

Where do you think this fits into health? I mean, this is clearly an important topic when we're talking about sports, right? When we're talking about endurance sports like running and cycling and swimming. The purpose of the sport is to be fast, is to have endurance and speed at that right. Combination. Many of the people listening to this podcast are no longer competing. You're still competing, but most people aren't. I don't compete at anything anymore, but I hate the term. But cardio exercise or endurance based exercise, we would still agree, is still an important pillar of health. So how do you think about that? And more importantly, how do you think about what you've studied, applying to health? And one of the things I want to talk about, because it's so interesting, of course, is at some point does exercise become counterproductive and maybe even what are the benefits, specifically, for example, energetics, efficiency with metabolism and how that can fight disease. So in any way you want to start that discussion, like, how do you start to think about it both scientifically and even personally?

Yeah, so that's a big bite to chew on. You've mapped out the next three hours of our conversation. One thing I would say is, I mean, look, I don't want to oversell it and say you must understand your absolute limits in order to be healthy. But if we think about the barriers to exercise, the barriers to being physically active, I think for a lot of people, if you interpret the distress signals you feel when you start exercising as signs that your body is reaching its limit, that's a very distressing thing. If you're like, I'm going to start an exercise program, I'm going to start brisk walking, I'm going to start running and you feel you're panting, you're out of breath, your legs are burning, you're like, I'm going to die, and you stop. And so I think understanding, it's not so much about how to change your limits, but understanding what those limits represent. Understanding that they are not signs that you're going to die. This is just information, I would say, and I haven't thought this through, maybe it's not true, but I would say off the top of my head, any meaningful form of exercise that's going to do you substantial amounts of good is going to involve dealing with discomfort in one form or another. And if you can get to a place where you understand that the feelings of discomfort are not signs that something is going wrong with your body, but they are just information. They are telling you where you are on the road to reaching your limits. And you don't have to go to your limits, but you also don't have to stop. You're allowed to just interpret that as information and say, okay, understood, I'm out of breath, but I can keep going. To me, at least, that's a useful insight to take from this. We can get deeper then into. You've raised some very interesting and controversial questions about how much exercise is good. What kind of exercise do we need to do? I don't know where you want to.

Start with that because we don't have three hours. Although when we meet in person and share a meal, we certainly will take those three hours. But let's start with two opposing points of view with respect to exercise. So one point of view says the exercise longevity curve is J shaped. So at the far end of the spectrum, no exercise is a really bad thing for mortality. As you increase exercise, mortality improves, improves, improves, improves, improves, improves. And then it kind of gets to your best. All cause mortality. And if you continue to increase exercise beyond a certain volume, this is generally discussed in volume of exercise. You actually see a little uptick in mortality, suggesting that once you go beyond a certain point, again, I want to stress this is in volume of exercise, you don't get any more benefit and you may actually have more harm. And a lot of times this is harm that comes in the form of cardiac dysrhythmia. Could be even atherosclerosis through endothelial damage, fibrosis, things like that. There's another body of literature that says, no, it's more or less a monotonically improving curve. And again, we all agree that at one end of the spectrum having really poor cardiovascular Fitness. Again, we could measure this in VO2 max or something like that. As that improves and you get fitter and fitter and fitter and fitter, all cause mortality goes lower and lower and lower. And there is no J to that curve. How do you think about reconciling those? And I want to point out at the outset, this is a discussion that only really impacts 1% of the population because 99% of the population are on the side of the curve where they could always benefit from exercising more. But you, for example, might be one of those people who's in the 1% where, I don't know what's your weekly mileage right now?

Fortunately it's only probably about 20 miles. So even James O' Keefe would give me a pass, I think.

Yeah, yeah, yeah. So walk me through how you think about that because I have to be honest with you, I've seen examples of those athletes who go a little bit too far, who probably have a genetic susceptibility to dysrhythmia and then they go on and get these dysrhythmias, but at the same time they're few and far in between. So I'm still a bit on the fence about this one. Again, just purely from an intellectual standpoint, I don't think it applies to me anymore. It probably did at some point.

It's a good question and it's an important one. And there's a few things I want to say. First, I'm a runner, right? So take what I say. Understand where I'm coming from. I'm also a human. Like I don't want to die. So I try to look at this data as dispassionately as possible, but obviously my knee jerk reaction is like, let's find holes in this data that suggest running is bad, so get that on the table. Second, there's no doubt that there is a reverse J curve. If you try to run 28, 20 hours a day, it's not going to be good for you. Nothing is good for you if you push it far enough. So the real question is, where does the uptick happen? Third thing I want to say is the data on this showing that, you know, you do a little bit, you get some benefits and the more you do, it gets worse and worse. One really interesting thing that came out of that, and there were a few studies about eight years ago that showed that is that actually the dose you need to get most of the health benefits is very small. And I do think that's an important message it's you do not need to train for or run marathons in order to be optimally healthy, at least to within the 90% or whatever. You're going to get most of what you get from a very modest amount of exercise. And so that's a great message.

Can you quantify that, by the way, in terms of running? Let's put some numbers to that. If you're talking about a person who maybe was active in high school and college, but they're 10 or 20 years out of that, they've been caught up in the challenges of starting their career, starting their family, et cetera. They wake up, they're 40 years old and their waist is five inches bigger. They've got metabolic syndrome. They're not in dire straits. It's not like they're going to die in the next 10 years. But they've got the message which says, hey, the one thing that is really missing is your exercise. What would you say if they scammed you and said, alex, just tell me the minimum effective dose. I don't want to run any weekend races. I like running. I used to love it. Or rowing or whatever their activity is. How many hours or how many miles do I need to do a week to just get 80% of the benefits with 20% of the efforts?

The Cooper Clinic study, which was like 50,000 people or so, that came out four or five years ago, their number was five to ten minutes a day. I don't fully believe that, but that was their number. So you're talking like an hour a week, and that's just going out for a run. Personally, maybe we can get into this. That's not my definition of an optimal exercise routine. I would include some high intensity stuff and strength is another thing. But there's making some claims about a very, very low minimum effective dose. Personally, I would say I'm probably running about 20 miles a week right now, which is six days a week, half an hour with a couple of hard days. To me, that's on the low end of, I think I would be healthier if I did more at this point. You.

Do you think you would actually be healthier? I know you'd be a better runner, but would you be a healthier? Would you live longer?

I think I would. The first thing I would do if I had instant motivation powder that I was going to dust on myself, I would up my strength training routine. That would be the first thing I do if longevity was my first priority.

Oh, I'm sorry, I misunderstood. So you wouldn't necessarily Run more. You would take extra time and add it in the weight room or do something else?

No, I would run more. If I was prioritizing, I would prioritize strength first. But I think because I come from a background where I'm already used to running 20 miles a week doesn't stress me very much. It just slows down my decline. I think I could benefit from, let's say one long, longer run a week or something like that. This is not supported by anything other than my gut. But so the five to 10 minutes a day, it's definitely the right place to start if you're the 45 year old sedentary getting back into it. But I think you might want to push something a little higher than that. Or certainly if you're doing 60 minutes a week, I wouldn't do it in five to 10 minute chunks. I would do some 20 minute chunks or whatever.

And what do we know about injury prevention in that person?

That probably they're going to get injured because they're going to find that no matter how metabolically unfit they are, they're probably going to find that they gain metabolic fitness more quickly than they gain tendon stiffness and muscle strength and things like that. So in a sense that's even more reason to sort of take that guideline seriously. I mean, I'm talking about running, which because I love, you're less likely to get injured if you go cycling or something like that. That's. Obviously there's other, other ways of mitigating the, the injury thing. But, but let me, let me just cast some doubt on the, on the J shaped thing. There were two main studies on which this whole J curve hypothesis was founded. One was the Copenhagen study and one was the Cooper Clinic study. The Copenhagen study, initially it came out saying running is great and more running is better. And then they reanalyzed it with a new co author and they concluded that running too much or too fast was bad. That was based on there were two deaths in the group that ran too fast. The confidence interval was essentially infinite. But there's a more serious problem, and it's one that affects the Cooper Clinic data too, which is that when you have a big study of 50,000 people who were just randomly selected, they're not all the same. They all have different characteristics. So you have to find some way of adjusting for various characteristics and without going too far down the rabbit hole. Basically, they statistically adjusted initially, at least for things like cholesterol levels, weight, blood sugar levels, blood pressure. It's meaningless if you compare like the non runners died sooner than the runners, but they were also 20 pounds heavier and had all these other risk factors. So you want to equalize it, but there's a problem that if you equalize it, you're essentially saying, well, what are the health benefits of exercise if you don't do any exercise? Because the health benefits of exercise are precisely in helping you regulate things like blood pressure and blood sugar and controversially, but I would say weight also. So to me that was statistical misconduct. You're saying if you take the people who exercise and you subtract, you basically penalize them for having lower weight, better lipids, better blood sugar, better blood pressure. So you bring them in line so that they're just as overweight and just have all the other risk factors, then you see this J curve. Now when they actually published the data in a peer reviewed journal two years after it was presented, they'd eliminated that statistical method and the J curve had disappeared. You no longer saw the J curve. I don't want to just dismiss and say, therefore there's nothing to see. I'm just saying that if we're talking about where the curve happens, if you do that kind of statistical adjustment, which is the equivalent of saying like, I want to know whether smoking causes cancer, but I can't compare the smokers and non smokers because the smokers have more lung cancer. So let's artificially equalize it and pretend that the smokers just have just as much cancer. I mean that you can't basically, in statistical terms, you can't adjust for a mediating variable, a variable that's affected by the thing you're trying to measure. So sorry, as you can tell, this is a topic I get excited about, so.

No, no, it is. And I've read what you've written about it, which is why I wanted to bring it up. I have a slightly different take on it, which is less about everything you've said and more of the practical issue. Because the practical issue is the one I get asked about a lot, which is am I exercising too much? Right. This is the person asking the question. And so again, let's pause it for a moment, that 99% of people are not exercising too much and don't even possess the fortitude to exercise too much. Right. The pain tolerance isn't there, the obsession with exercise isn't there. So for 99% of people, we'd like to get them to exercise more or stay the same. We're dealing with 1% of the population, many of whom I know and one of whom I used to be, that were kind of the hyper exercisers. Here's the bigger point I would make. It's probably less relevant whether or not they're spending too many hours cycling, swimming, running, et cetera. Usually people in this sense, it's not the number of hours they're spending, it's the portfolio allocation of how they're spending it. That's the bigger problem. It's that they're not well rounded and they're not actually in pursuit of longevity. So the reality of it is, is training for the Tour de France is going to increase your longevity. Absolutely not. No way. Like those guys finish the Tour. Anemic osteopenic, their upper bodies are emaciated, their posture is horrible. There is nothing about that that is setting you up to be an octogenarian that kicks ass. Nothing whatsoever. So their physiologic marvels, but their health span sucks. So using that as an extreme, how would we extrapolate that to the 40 year old who just can't hang up the dreams of being a professional athlete who's out there running or riding or doing all of that stuff nonstop, but at the expense of maybe not doing some Pilates to work on core strength? I hate the term. But you know what, just for people that understand what I'm saying, like not working on stability, not spending any time in the weight room really working on strength, not varying the intensity of their workouts to work different energy sources. So to me, that's the bigger issue with people who are exercising too much. It's probably not that they're at the little tip of a J that may or may not exist, it's that they're squandering their time. It's like having all of this money, but you're invested, you have a lousy portfolio.

Yeah, okay, I agree with a lot of that. One thing I'll say is the important question you're implicitly asking there is what's your goal? What are you training for?

Well, that's why I said longevity. This was all predicated towards living a longer, healthier life, not winning races or whatever.

I would 100% agree. If someone comes to me and says, I want to optimize my exercise program for longevity, like I said before, there's no way I would tell them, you should be training for a marathon. That's not because I think training for a marathon is bad. But like you said, it's an opportunity cost of other things. You could be doing that a lot of other things you could be doing that would probably work better. So I think it's really important to disabuse people of the notion that in order to optimize your health, you should run a marathon. But where I bridle with the media coverage of that stream of research is that that's different from saying that people who are training for a marathon because they want to run a marathon or because they want to run a marathon as fast as possible should stop, because that's bad. So it's like of the category of people who have unhealthy behaviors, who we should intervene to save them from themselves. They, like. People who are training for a marathon, to me, are not even close to being in the same category as people like me who are sitting at a desk for eight hours a day or whatever the case may be. So it's like there's a difference between optimizing and avoiding serious problems. And the one other thing I should acknowledge is, and you alluded to it, is there are other potential issues with lots of endurance training, and arrhythmias is one of them. And there's better evidence that that's a real thing. There may be downsides to training really hard. On balance, overall, I would say I don't lie awake at night worrying about people who are running 50 miles a week.

Yeah, you're right. You should worry far more about people who are eating poorly, smoking, who are stressed out of their minds and don't have coping mechanisms for them. There's not many people that you should be worrying about, more or less, rather.

And if I think of the people I know who, let's say, run the equivalent of 50 miles a week or more, I can't think of any of them who would say I'm doing this because I think this is what I need in order to optimize my health span or lifespan. They obviously hope it's healthy, but I think if you're training for a marathon, most of them are doing it for competition, self competition, in a way. And it sort of reminds me of something. You discussed this a little bit, I think, in your conversation with James o'. Keefe. The. What's great about tennis and badminton and volleyball or whatever? What's the social element of it? And I think, sure, on average, running is a solitary sport, but for me, it's my primary social outlet. It's where I meet my friends. It's where I get together and catch up on the week on an easy run. So it's like, I think that's True for a lot of people who, once you get into that 50 miles a week, not for everyone, but for a lot of people it's a social element, it's pleasurable, it's a stress reliever. So if you take that away, I'm not sure it nets out as positive.

One of the things that I think is I don't know that we'll ever have an answer to the question. But I think one of the challenges of trying to reconcile all of these disparate data sources is it's all apples and oranges with respect to the metrics, right? You're comparing hours of exercise a week to mileage run to true measures of fitness like VO2 max. I guess the question is, and I've thought a lot about this, I'd be very curious to your thoughts if you could reverse engineer where you want your VO2 max to be when you're 90. What should it be? Because if you have a sense of what your VO2 max should be when you're 90, you kind of know what it needs to be when you're 80, 70, 60, blah, blah, blah, all the way back. And at that point it's not necessarily about how fast you want to run a mile, though you may say, look, when I'm 90, I still want to run a nine minute mile. I don't know know. But it really starts to get into the activities of daily living. And how much pain are you willing to tolerate to walk up two flights of stairs with your groceries?

I hypothesize for me that when I'm 90, that the real risk is that I won't be able to get up out of a chair. More than that, I won't have the VO2 Max. And there are, I don't remember the exact numbers, but there are thresholds of VO2 max below which they hypothesize that you can't remember if it's like 18 or not. Maybe it's 9 or something like that, where it's like, at this point you've crossed the sort of mortality index where we think you're going to die in a few years because you can't do activities of daily living. So there is some research into that. But for me I can look at myself and say, you know what, Alex, far before your VO2 max is too low, you're going to be the guy who falls on the floor and can't get up. And so again, from a health perspective, that's why I said the next thing. If I had magic, motivation, dust, it would be like, you need to put on some muscle mass. And for other people, it would be totally different. There are people I know who don't necessarily exercise a lot, but who just have a lot more muscle mass than me. And it's like, you need to make sure your aerobic fitness is taken care of and maybe you don't need to worry as much as me about muscle mass. So there's. I mean, I agree. You figure out where you want to be and for all those different things. So I'm doing exactly what you said, except I'm doing it for muscle mass. And I'm like, ooh, this trajectory is not good.

And of course, part of that's predicated on the idea that we know there's an inevitability of decline. So if you do nothing, you're going to lose X pounds of muscle per decade. If you're lucky with a tailwind, if you train really hard, you might be able to reduce it to this amount of loss. And if you really go crazy, you might even be able to keep it flat. But here's the scenario under which that occurs. I assume there are pretty clear tables on what the decade by decade drop of maximal aerobic output is. There are.

I mean, the problem with the tables is that they draw a nice smooth line. Do you lose? I think it's 9% per decade or something like that. At least in the. Once you get into your 70s, it gets steeper. There's an inflection point. The sort of revised thinking is that that works on a population level, but what actually happens is the decline is not that steep for any individual. But what happens is you have certain events in your life. You have a knee replacement, you get.

An injury and you stop training for six months and then you're hosed.

Yeah. So either you have reduced activity for six months or you have bed rest for a week, which can be disastrous, and you lose 7% in the course of a week and you only get 2% back. And so it's this punctuated decline. And so, I mean, that puts a lot of emphasis. It sort of points to the idea of really taking care to avoid, to the extent possible, obviously, to avoid these sorts of events, because you can actually, in the absence of those events, the decline doesn't have to be that steep. You can hang on probably better than people used to. Think, think.

Can you say more about that? Because I don't think this point can be stressed enough. Realistically, how much aerobic capacity, maximal aerobic capacity, can a person lose with a Couple of weeks of inactivity. And what's the difference between being bedridden versus going on vacation to Europe where you're not quote unquote, training, but you're still walking every day? Neither of those is exercise per se, but one is active and one is complete inactivity.

Bed rest is terrifying. There's a guy named Luke Van Loon in the Netherlands. His focus is muscular strength, but he's done a bunch of bed rest studies. I saw him give a talk once and he had this great anecdote about they'd spent a whole. It's really hard to get old people to put on muscle, right? But they just managed to finish this two and a half year study where they got, I can't remember, some fairly large number of septuagenarians, octogenarians, to do strength training. And they'd put on like two and a half kilograms of muscle, which is a huge victory. And they were feeling really good about it. And then the results came in for their one week bed rest study and they'd lost like 2.6kg of muscle in one week. So it's like they did this like herculean effort to shepherd these people through strength training for a long period of time with full support. But man, whatever it is, you know, grandma gets pneumonia and is in hospital for a week, bam, she's lost a year of training or whatever the case may be. So I don't have the numbers at hand for V2 max. I think it's like up to 10 to 20% in that range. If you stop training for a month. It depends where you're starting though. If you're well trained for a short period of time, you'll lose it quickly. If you haven't been training, then resting doesn't make any difference. And if you're well trained for a long, long period of time, then you have structural adaptations that are going to take a lot longer to disappear. So there's no one number for anyone. And the one thing I would add is that this is not a recommendation that you should never take a break from exercise, that you should be obsessive, train 365 days a year. Certainly if you're training hard, like if you're training as a marathoner, say, man, you should take a week or two. Off and off doesn't mean bed rest. It means play a couple games of tennis, go for walks, chill out, go for some bike rides or whatever. So you shouldn't be terrified of missing a day, but you should be terrified of bedrest. I Mean, Luke Van Loon, One of the things he said is, like, if you're on bed rest, hospitals should be forcing you, if you're at all possible, to walk down the hallway to get your meal. Even just walking down the hallway is infinitely better than not moving at all.

God. Never more sort of relevant than what we're seeing today with so many people in hospitals and a lot of the isolation stuff that's going on. Let's go back to something you said about strength. What do you think matters more? Strength or muscle mass?

There's a study I wrote about recently. I would hesitate to claim it as the absolute truth, but I think it put together like six different cohorts with a total of about 50,000 people. So. So pretty good data. And they found that strength was actually a better predictor than muscle mass. So it's better to have the functionality to be able to push yourself up out of the chair than it is to have a bunch of muscle if you're not good at using it. I'm sure that's maybe not true at the margins. If you lose enough muscle mass, then you become limited by your actual muscle mass. But I think for a lot of people, they have enough muscle mass, but they're untrained. The neuromuscular connections are not optimized. And so they're just. They're not strong even though they have enough actual flesh there.

And was that for all cause, mortality?

Yeah.

So that's interesting. That doesn't sound like a crazy conclusion. I generally try to say, look, I think both of these things are important for different reasons. Right. I think of strength as you described it. It's that functional. It's the difference between the person who slips down the flight of stairs but has the strength to grab the rail and prevent that, you know, from being a lethal injury or the type of injury that puts them in the hospital for a month. You know, grip strength is just so highly correlated, at least with survival. And I think a lot of it has to do with that kind of stuff. Getting up out of the chair, getting up off the floor. At the flip side of that is, I think muscle mass speaks to some of the other physiologic things like glycogen stores and glucose disposal and glucose homeostasis in general, insulin sensitivity. So again, I rail against the idea that people say, I'm okay being strong. I just don't want to be big. And it's sort of like the myth of accidental muscle, you know, I wish.

I had that problem. It's like Oh, I looked at a gym and I accidentally put on 10 pounds of muscle. Yeah, yeah, yeah.

I hear people saying that and I'm like, I wouldn't worry about that. Anything else about injury? I mean, you've written a lot about this in terms of different competing theories around injury and how much do you think it varies by sport? And I guess, most importantly, what is the implication for people who tend to get injured in life? They're walking down the street and they pull a calf muscle versus they're out there doing their tempo run.

I've been willingly or unwillingly embroiled in lots of debates about injuries over the last decade and a half, and a lot of them focus on things like running shoes, the proper running form. Is the height of your insole going to affect your risk of injury? And that stuff's fun and it's not zero impact. But there's a guy named Ben o' Nig who's a sort of famous biomechanist who's done a lot of work on running injuries and stuff. And his take in one of his studies was that, look, 80% of running injuries are a result of what he would call training errors. So, yeah, it's nice, you know, there's 20% to work with on shoes or whatever. Prehabilitation and balance, yada, yada, yada. Most of what we need to worry about is doing too much too soon. And that's an oversimplification. But certainly when we're talking about overuse injuries, I'm not talking about like getting tackled on the football field. I really think for people who are starting out or ramping up an exercise program, that patience is so important and that understanding that you will probably overestimate what you can accomplish in the short term, and you'll probably underestimate what you can accomplish in the long term. And if you fall into that trap, you're dramatically raising your injury risk because you're going to try and ramp up too quickly. Because again, you can gain metabolic fitness more quickly than you can alter the structure of your joints and ligaments and things like that. So if there's one takeaway message, it would be like, it's not about the magical gadget or the new way of running or the measuring device. It's like, just be patient, be smart. You know, you get home, you have something that's aching, you don't want to miss the next day's session, then you don't want to become. It's always a balance, right? Between being, am I being lazy? Or Am I being safe? Well, you want to err on the side of safe, certainly, until you start getting a better handle on which aches and pains are normal and which ones aren't. We can get into things like balance training or training load monitoring, you know, acute versus chronic.

Yeah, let's talk about acute versus chronic load training. I mean, I used to have a program called Training Peaks that would track this for me. So it saw every single day how many miles I rode and it actually did it more by kilojoules than miles. So it was total energy expenditure. But if you were giving someone some guidance, some rules of thumb, if they were becoming active, and we don't have to get into the formulas, but just using the principles of acute versus chronic load balance, how would you help them think through everything you just said with these metrics?

The rule of thumb that they used to teach runners is the 10% rule. Never increase your mileage more than 10%. And it's a rule that makes no sense at the, at the margin. So like if, if you start by running one mile, then you know you're never going to get above 5 miles in your lifetime or whatever. But basically the idea is trying to avoid the too much too soon problem. Now this idea of an acute to chronic workload ratio is a sort of more sophisticated version of that. And the idea is how much are you doing now versus how much is your body used to. And the way that the academic papers do it is what's your weekly load, whether you do it in joules or miles or minutes, and what's your average weekly load over the last four weeks? When they started publishing this, I was like, hey, I designed my own training log back in the 90s and printed it out. The two things I had at the bottom was kilometers that week and four week average kilometers.

Why did you settle on four weeks by the way, as opposed to three weeks or five weeks? How did you arrive at that? Do you remember?

Yeah, there was no deep thinking involved. It was basically a week versus a month. And you can argue it that you need a decent amount of time because otherwise you have one week where you miss a couple days due to injury and then all of a sudden you're four week average is totally skewed. Or if it's a three week or something and five weeks, six weeks, at a certain point you're moving so far back that your body no longer cares what you were capable of doing eight weeks ago, or at least not as much. So four weeks is just a, it's kind Of a. If you've done something for four weeks in a row and you're feeling okay, then you can. You kind of assume that, yeah, your body's able to handle that load. So then this allows you. It's just a quick way of seeing if there's any deviations. It's like this week I did 50% more than my four week average. That's a bad, bad sign. It doesn't mean you're going to get injured. There's all sorts of contextual things you have to consider in it. But having that as one input into your larger matrix of all the things that you're considering, like do I feel any aches and pains? What's my absolute load? Not just the ratio, but is this more than I've ever done before? You consider all those things and I think that acute to chronic ratio, or just to put it more simply, keeping track of how hard you're going now versus how hard you've been going in the previous month or how much you've been doing, let's say, is useful. Now, I should add that there's controversy in the literature. There's a bunch of people who say that the supposed predicted value of acute to chronic workload ratio is a statistical artifact. It may be, it may not be. I'm not too worried about that. To me, this is not about statistical predictive power. It's just about keeping an eye on trends and knowing if you're way out of whack with what you've been doing before. And as a general rule, you know, let's say if you're 20% higher, that's time to start making sure you know what you're doing.

Yeah. And backing it off. Maybe that next week.

Yeah. Unless you have some compelling reason to think that you can handle that. If you're exceeding 20%, then yeah, be cautious and ideally back off.

So you alluded to it earlier, but let's talk a little bit about high intensity interval training. It's getting a lot of attention today. Obviously most people are familiar with what a Tabata is, though Tabata himself is not the guy that actually designed the protocol, but everybody still refers to it by his name. Where do you think this fits into the hierarchy of. Again, not a specific athlete who's training to run the mile or the marathon, but a person who's trying to be healthy, who. How much of a shortcut efficiency gain is it? Again, let's use the Tabata interval as an example where you're going all out for 20 seconds, resting for 10 and repeating it eight times. And by the way, wouldn't we argue from your research in Endure that you can't technically go all out for 20 seconds that you're. I've started. When I do all out intervals, I now limit them to 10 seconds because I actually started paying attention and realizing I was subconsciously pacing myself at 22nd all outs. But anyway, I don't know what you think about that idea, but I remember reading in your book, wasn't it the case that we technically can't go all out for 20 seconds?

It certainly doesn't seem that way. And like Usain Bolt or world class sprinters don't go as fast. I mean, it's complicated by the curve. They don't set world records en route to 200 meters. They're pacing themselves even for 20 seconds. I just have to tell one quick story about Tabata. I was at a conference at the poster session where the researchers are in front of their posters talking about it. And it was a research from the McMaster group which has popularized high intensity interval training. And one of the postdocs was there explaining his interval high intensity interval training research. And someone came up and asked him a question and handed him his business card at the time. And I noticed the postdoc, he looked down as he was answering the question. He glanced down at the business card and his eyebrows just went like, like halfway up his forehead. And I peeked over and it was like, oh, that's Tabata. That's cool. I didn't realize this was a real person. So he was, he was there, you know, asking questions about intervals. Anyway, where do I think intervals fit? I think they're super important. When circa 2008, when high intensity intervals started to be a big buzzword, I was like, how is this a buzzword? That's how runners train. Like one of the studies out of the McMaster group was like, let's do 10 times a minute. It's like, that's the Roger Bannister. That's what. That's how he broke the four minute mile in 1954. What's new about this? But it was new to a lot of people. A lot of people were like, I need to go 45 minutes, I need to go an hour, I need to do this, I need to die.

I guess what I was really getting is the compression of that, right? It's the. I don't know if you saw this. Well, I'll let you finish this, but then I'll bring it to where I'm going. Which Is what are the limits of how much you can shrink that?

How low can we go?

Yeah, yeah, yeah. How low can you go? But, yeah, but keep going with that.

Yeah, I'll just say that as two general points. One is that as a runner, one thing I know is that you will never ever run fast relative to your abilities if you don't do interval training. The second thing I would say is you probably won't run as fast as you could if you only do interval training. Now some people do do only interval training, but that's usually they're doing it so slowly that it's not different from just doing a sustained thing. So to me, when you look at the studies like let's compare eight weeks of three interval workouts a week to eight weeks of three 45 minute sustained sessions, it's like, okay, that's interesting, it's useful to know, but I really don't think that's what is optimized. And what we should be comparing it is what about one short sprint interval session, one medium interval session and one 45 minute session or some portfolio? Because there's pretty clear evidence that you can get to the same, are some of the same health outcomes, you can get the same improvement in insulin sensitivity, say, but the mechanisms may be different if you're doing a sprint interval session versus or if you're doing sprint interval training versus sustained training. And so it's like, well, if you've got two different mechanisms, let's hit them both. Because presumably we're going to get a little one plus one is going to be at least equal to, we know, 1.2 or something like that. So I would 100% recommend to anyone that they should be including some form of interval training in their routine if they're interested in health or performance. I wouldn't necessarily recommend it. It's the only thing, unless that's what they want to do. I would put it as part of a portfolio. And as far as the sprint stuff goes, we could talk about this. But it has been funny to watch the. It's not like one upmanship, it's one downmanship. How short can we make? It's like, okay, I thought about interval training for a millisecond last night. Look, I got fitter. It's amazing.

Well, that's only a slight exaggeration from a study that came out recently from here in UT Austin. Ed Coyle, who is a physiologist and published a study looking at 4 seconds all out, 56 seconds of rest. So it's Every minute on the minute, but only four seconds all out. And this was done, I believe, for 15 minutes. And then they progressed to basically four seconds all out, twice a minute. So you go four seconds all out, 26 seconds of rest, repeat for 20 minutes, something to that effect. Here's my take on these things. It comes down to a concept you raised earlier, which is there's an opportunity cost to them. They're usually comparing that to doing nothing. And is that better than sitting on the couch? Yes. But if you gave me 40 minutes a day, could I come up with a more efficient way to get a benefit? I probably could. And then it becomes a question of what's the efficacy versus effectiveness of this intervention? And I think that's the other piece of this, Right, which is I think people like you and I like exercise so much that we get to focus all of our effort or interest on efficacy. What is actually going to do the best, produce the best results when adhered to perfectly. But I accept the fact that many people don't enjoy exercise. And therefore the real world applicability of a problem becomes its effectiveness. It's not what can be done in a laboratory for six weeks when you're a paid subject, it's what are you going to be willing to do on your own when you have to rely on your own sprinkling of motivation dust day in and day out. And so I guess on some level that's where I've become a little bit more accepting of the fact that, hey, if people are willing to do shorter interval workouts, provided they don't get injured, that's always the fear I have when people jump right into these high intensity interval workouts without any of the foundational strength that goes into it. If the alternative is doing nothing, well, then it's better. But I guess secretly I just hope that I can convince people that they're better off learning to love exercise. Which again, I think is why a book like yours is so great. Right. It explains how we evolved. And the more we can think about reconciling what we are today with what we spent a million years becoming, perhaps the less foreign that feels.

So I think you've put your finger on exactly the issue, which is, yeah, it's not about what does better in this lab context, it's what will people do. And I actually, I'm a little bit skeptical that four seconds at the intensity that you have to do those intervals is more acceptable to the average person than, let's say, one minute. So going back to a little History on the HIIT stuff. The first hit protocol was Wingate test which is like 30 seconds all out. And anyone who's done a Wingate test, you know, if you do it in the lab, they're screaming at you. It's like, you know, we're going to shoot your mother if you don't go as hard as you can. And you get every people puke after wingate tests. So the Original protocol was 4 Wingate tests with 7 minutes rest because that's how hard they are. It's like what we were saying earlier about how hard an 800 meter race, a 2 minute race can be compared to like a marathon. You can really suffer in those 30 seconds. And so when they're like, well okay, it works in the lab, but in real life, what are people going to do? Their answer initially wasn't like we should make it shorter. It was well, the intensity that people can actually get to in real life. That's where the 62nd on, 62nd off protocol came from. Because it's like it's easier for people to accept 60 seconds pretty hard than it is to expect them to imagine the, you know, homicidal drill sergeant behind them yelling at them to get all of it out of themselves in 30 seconds. Now you're going down to, let's say there's been 20 seconds, there's been 10 seconds, there's been four seconds. It's hard. It takes a lot of motivation. You have to be 100% on to get the most out of this 4 second or 10 second or whatever interval. So there's a lot of debate understandably about like okay, well which is it that people will do? Would they rather do 20 minutes at medium or 40 minutes easy or 4 seconds hard? I think there's a lot of debate because there's different, there's a lot of different people, people like different things and some people are love that, that, that power thing and that that's great. And again like you said, it's. I don't think it's as good as doing a mixed portfolio of things, but I think it's pretty good and if they'll do it, that's great. But I think the assumption of this race to the bottom of how short can you make the interval is that people like it more. I'm not sure that's true for everyone.

I love your comment about, I thought about high intensity intervals for a second last night. I will say this. One of the things that I think is a big challenge here is most people aren't clear on the why, they just want to do the what. This is sort of going back to my pet peeve of people confusing strategy for tactics. I think if people don't understand the benefits of the different types of exercises and why you're doing them, actually reverse engineering what the purpose is. So you're thinking about the 90 year old version of you in a chair, he needs to get up. Well, that gives you the motivation to do strength training. And if you didn't have the aerobic conditioning, you'd start to think, well, once I get up out of said chair, what do I want to do? Oh, I might actually want to go and walk around the block with my grandchild. Oh, well, what would that involve? Well, at my house there's a hill and that hill goes from here to there. And what if I want to stick them in a wagon and pull them? That's actually going to require aerobic capacity. And that hill is pretty short, so it's actually going to be pretty intense. It actually requires a near maximal effort for me. And so I just think that the more people can tether what it is they are doing this for to something real, it becomes a little easier to do these abstract workouts because otherwise what are we doing? Once you stop competing in something which is a fraction of the percent of the population, all this exercise stuff becomes abstract. And frankly, the practice of medicine doesn't do a great job communicating the why. I mean, most, most people know they should exercise, but I don't think they've really had a great explanation as to, for example, fighting cancer when you're fit is probably a lot easier than fighting cancer when you're not fit, simply based on the energetics of your immune system. Most people don't know that and therefore it's a bit abstract why they should be exercising so much.

Yeah, I mean, you could say the definition of insanity is telling people that exercise is good for them yet again and hoping that that on its own is going to convince people to exercise. It's clear that doesn't work. So I think what you say is right. You need to make it visceral and to relate to things that people care about and so that people care about different things. So you have to understand what each person cares about and then find out what the right exercise for them is. That's going to connect for them.

Last thing I want to ask you about, Alex, is basically the merger of the two careers you've had. I've probably been pretty critical of your profession, which is science journalists or Journalists who cover science, let's put it that way, because truthfully, I think most of them are really bad and I think many of them actually border on negligent. And I think they cause on some levels more harm than good to the public. Obviously I don't put you in that category. And there are many people I don't put in that category who I think are excellent at science journalism, but they're really in the minority. So most of the sensationalized headlines and frankly even the news stories that just don't have the detail that I think should at least be covered in a news story, given the understanding that very few people are going to go back to the primary source and read it, places an enormous responsibility on scientific journalism. Do you think there's a systematic way to make this process better?

Oh, that's a heavy question. My perception as the problem, and this is self serving, since I'm a science journalist, is that journalism now follows the audience. You know, and I started out in 2006, let's say just at the point where news organizations were first starting to be able to see how many people clicked on a story. And this was, you know, one of the great catastrophes of journalism in some ways because it's terrifying to find out what people click on. It's unhealthy for the news organizations to find out what people click on. I can remember. So the big newspaper in Canada is the Globe and Mail. And early on as newspapers went online, they started to. People realized it's kind of nice to have what are the top 10 most clicked on stories. So then you can go, and I remember when the Globe, as far as I remember, I don't know the exact timeline, but shortly after they introduced this feature, I was like, how is it that the top 10 stories on the Globe and Mail website, like three of them are about Britney Spears? It was just like the Globe and Mail is supposed to be the kind of highbrow newspaper in Canada. And it looks like it's a bunch of simpering morons who are clicking. But then I look at what I click on sometimes and it's like sometimes you're just tired and you click on the sort of craziest thing. So anyway, sorry, I'm drifting off the point here, which is that to encourage good science journalism, you need people to read good science journalism. And I think newspapers are realizing that following the audience has turned out to be a bad move because they've ended up losing the trust in audience. But by giving people what they thought they wanted you ended up basically giving them crap and then having people recognize that they were being fed crap and then rebel against it. So where I started my sports science journalism career in some sense was I started a blog on WordPress in like, I don't know, 2008 or something where I was just like, you know what, I can't write this in a newspaper article, but. But on this blog I know there are people who are interested in the details of what the study says. I'm going to have the key figure from the study and I'm going to say how many subjects there were and what their characteristics were and what the intervention was. That's the blog that became. It got taken on to runner's world in 2012 and then moved over to outside in 2017. It turned out there was an audience for that, which is encouraging. So I think, I guess I'm not answering your question at all, which is how do you fix it? But news organizations aren't going to insist on scientifically qualified journalists unless there's repercussions or feedback when there's bad journalism. And I think the initial signals were the opposite. They were actually getting feedback that the less complicated it was and the more sensational it was, the more feedback they got to try and actually give. One concrete answer to your question is that the move away from advertising and towards subscription based models I think has helped and hopefully will continue to help move away from just let's do what's most sensational to let's give people a filling meal that they're not going to be hungry 10 minutes later. So maybe that trend is a good one in some ways.

And look, I don't know that I expected you to have an answer because this is a question I've thought about for a decade. Actually probably around 2011 is when I started really becoming frustrated with journalism and science. Which is not to say that's when it started. I think that's just when I began to notice it enough and realized that the signal to noise ratio had fallen to zero. And if you ask my friends, there's no better way to drive me nuts than just to forward me a headline without even a question. As though somehow I'm supposed to read this idiotic headline and know what your question is of me. But look, I still get three of those a day, so. So anyway, Alex, this has been awesome. Like I said, I've wanted to sit down with you for a couple years since I read Endure and I can't recommend it highly enough. I find it riveting I think you're a great writer and a great storyteller, and that's to me, I think one of the gems of reading a book like that is you're reading about science, but you're also reading it in the context of amazing stories, personal stories, stories of other individuals. So thank you very much for that contribution and all of your amazing stuff on Outside, which I again, I can't get over how prolific you are and it's just, it's gem after gem.

Thanks Peter. It's been a real privilege to have a chance to talk to you and I've appreciated your work over the years and I really, I'm glad we had a chance to talk and I'm just sorry my answers were so rambling.

Not at all. Thanks Alex Peter, thank you for listening to this week's episode of the Drive. If you're interested in diving deeper into any topics we discuss, we've created a membership program that allows us to be bring you more in depth exclusive content without relying on paid ads. It's our goal to ensure members get back much more than the price of the subscription now. To that end, membership benefits include a bunch of things. One Totally kick ass comprehensive podcast show notes that detail every topic, paper, person, thing we discuss on each episode. The word on the street is nobody's show notes rival these monthly AMA episodes or Ask Me Anything episodes episodes Hearing these episodes completely access to our private podcast feed that allows you to hear everything without having to listen to spiels like this the Qualys, which are a super short podcast that we release every Tuesday through Friday highlighting the best questions, topics and tactics discussed on previous episodes of the Drive. This is a great way to catch up on previous episodes without having to go back and necessarily listen to everyone. Steep discount accounts on products that I believe in but for which I'm not getting paid to endorse and a whole bunch of other benefits that we continue to trickle in as time goes on. If you want to learn more and access these member only benefits, you can head over to Peterattiamd.com forward/subscribe. You can find me on Twitter, Instagram and Facebook, all with the ID Peteratti md. You can also leave us a review on Apple Podcast or whatever podcast podcast player you listen on. This podcast is for general informational purposes only and does not constitute the practice of medicine, nursing or other professional healthcare services including the giving of medical advice. No doctor patient relationship is formed. The use of this information and the materials linked to this podcast is at the user's own risk. The content on this podcast is not intended to be a substitute for professional medical advice, diagnosis or treatment. Users should not disregard or delay in obtaining medical advice from any medical condition they have, and they should seek the assistance of their healthcare professionals for any such conditions. Finally, I take conflicts of interest very seriously. For all of my disclosures and the companies I invest in or Advise, please visit peterattiamd.com AB out where I keep an up to date and active list of such companies.

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