#218 - AMA #38: Can you exercise too much?

Hey everyone. Welcome to a Sneak Peek, Ask Me Anything or AMA episode of the Drive podcast. I'm your host, Peter Attia. At the end of this short episode, I'll explain how you can access the AMA episodes in full, along with a ton of other membership benefits we've created. Or you can learn more now by going to peterattiamd.com subscribe so without further delay, here's today's sneak peek of the Ask Me Anything episode. Welcome to Ask Me Anything episode number 38. I'm joined once again by Nick Stenson in today's episode. We dive in really deep to this.

Question around exercise and if there is.

Such thing as too much exercise.

Obviously, we talk a lot about exercise.

On this podcast, and that's for pretty obvious reasons. Namely, it's perhaps the single most important tool we have to live longer and live better.

However, we often get asked a lot.

Of questions about the optimal dose of exercise for longevity. So it's a topic where there's a lot of confusion in the literature and we've even had previous guests on the podcast who disagree with each other on what those answers ought to be with respect to the dose of exercise. So for this ama, we compiled all the questions that you've asked around this and we've now taken the hard look at this. So which studies say what things, how contradictory are the results? And we do this primarily by looking at the so called J curve. The J curve meaning that as you go from being sedentary to being active, your risk of all cause mortality declines. But then something paradoxical seems to happen, which is after bottoming out, it starts to uptick again. The so called J suggesting that once you go beyond a certain point, that is to say, once you exercise beyond a certain point, your risk no longer stays low, but actually starts to go back up.

Now, this episode took a lot of time.

In fact, we were going to record this episode about two months earlier, but I just didn't feel we had done.

A deep enough dive so we delayed it. And the reality of it is there's.

So much here that we just can't.

Discuss in a podcast because the podcast.

Would be too many hours.

So what we do is we talk about everything.

In summary, we deep dive into a handful of studies, we discuss some of the illustrative critiques on all sides. But really, if you want to see.

This at the deepest level, I would.

Encourage you to look through our show notes where we're going to link to all of the analysis that's been done on each of the studies. So if you're a subscriber and you want to watch the full video of this podcast, you'll find that on the Show Notes page. Also, if you're not a subscriber, you can watch a sneak peek of this on YouTube. So without further delay, I hope you'll enjoy AMA number 38.

Peter, how you doing?

I'm good, Nick.

How are you?

I'm doing good, man. You ready for another ama?

Sure am.

All right, well, this one, I think, is on a topic you're a little more excited about than maybe the Fruits and vegetables 1. Looking at exercise. So there's been no shortage of things that you've spoken about exercise and how positive you are on it. You've often talked about how it's one of the most potent things we have in the toolkit for longevity. And whenever you talk about it, we get a lot of questions from subscribers. A lot of people wondering, how should they think about exercise? Like, what is the optimal dose of exercise for longevity? And I think we see this anytime we do an exercise podcast because you have your four pillars of exercise. And so people are always wondering, how do I get everything in? How much should I be working out? I think some of the confusion can also come from past guests maybe having different opinions. I think when you look at the literature, it also doesn't quite agree with each other, you know, so if you take someone like Alex Hutchinson and you take maybe the AMA you and Bob did on VO2 max, and you talked about how important that was, and then you have a podcast like we did with James o', Keefe, where he and his research talks about a J curve. It's kind of hard for subscribers at times to understand the literature, right? How do you get an elite VO2 max when some of the other research says the best thing you can do is play badminton? Those two things don't quite add up. And so what we did for this one is we compiled all these questions around this to really try and answer the question. The core question, which is what is the optimal dose of exercise for longevity? And quick disclaimer is we're not looking at what is the minimum dose, Which I think gets written about a lot. And I know we've done weekly emails, kind of responding to articles that are like 10,000 steps, 10 minutes of walking a day. All these little things are all you need to do. So we're going to focus on that core question is like, what is the optimum dose? So before we get into those types of questions that we compiled Anything you want to add to what I just said to set the stage?

Yeah, I would add that we're also going to explore can you do too much? Because most things in biology occupy a Goldilocks space. Not too much, not too little. Clearly that's the case with nutrition. Too much nutrition, Just look around you. Too little nutrition. Well, that's frankly the problem that lots of parts of the world still experience and have historically experienced a lot of sort of with exercise, I think that's less clear. And that's a topic we also want to really get into today. And even if that's not relevant to the majority of the population, in other words, even if majority of people aren't in the situation where they're butting up against potential limits of exercise in terms of crossing from being benefit to risk, I think it's a very important question nevertheless, and it might speak to some of the mechanistic insights around exercise. And of course, for those people who do want to push the limits, it probably gives us some insight as well.

So maybe we just start with one of the first questions and it's something that you've covered before, so we don't have to go into it in an insane amount of detail. But I think it might be helpful for people just to set the stage on why they should care about this and why it's worth putting in the time to exercise. How is exercise so beneficial not only for our health span, but also for our lifespan? And you kind of tried to summarize it in a cartoon you put on Instagram the other week at this point, which kind of looked at the guy in the doctor's office and the doctor asked him like, what would you rather do exercise one hour a day or be dead 24 hours a day? And so anything that you can kind of do to set the stage on why this is so important and why people should make the time for it, should put the effort in to understand this.

To your point. I think at this point there's really no need to spend time discussing this beyond just stating that regardless of which chronic disease you're looking at, whether it be ASCVD, cancer, type 2 diabetes, Alzheimer's disease, all cause mortality, it doesn't matter. Exercise is going to reduce the toll of mortality across all of those things. The mechanisms by which it does it can be interesting. So it can improve lipids, it can reduce inflammatory markers, it can reduce flow mediated shear stress in arteries. Can cancer truly, It's a little bit less clear. I suspect much of the benefit in cancer comes through the metabolic benefits of exercise. So we know, for example, that the second leading environmental or modifiable risk of cancer after smoking is in fact obesity. And as I've probably talked about in other podcasts, I think it's really less the adiposity of obesity that's the problem and the metabolic consequences of obesity that are found in many, but not all obese patients. Obviously, diabetes is probably one of the most clear places where you just dramatically see an improvement. And this of course, has to do with glucose disposal and insulin sensitivity within the muscle. And again, I think the list just goes on and on and on. But there really isn't any ambiguity here. And again, we should sort of celebrate this fact because there's a ton of ambiguity in a lot of things that pertain to lifespan and health span. It's actually nice for once to have a slam dunk.

I think what would also be helpful for people is another term I've heard you mention before. Internally, as you think about your exercise and how you plot out how you tackle this problem is mets. So do you want to let people know what a MET is and then why it can be beneficial in looking at a variety of different exercises?

I do talk about it a little bit, and I think most people have heard of this idea of a metabolic equivalent or a met, and it's basically an energy currency in the body. We think about energy currency in sort of ATP, but that's on such a cellular level. This is kind of a global way to think about it. One MET is the energy cost of being alive at rest, so obviously not a whole lot worth noting. That one MET is equivalent to 3.5 milliliters per minute per kilogram of oxygen utilization. And that relationship for the most part, just holds. So in other words, if you are doing 10 METs of exercise, you are consuming 35 meters milliliters of oxygen per minute. And that becomes relevant as we start to think about VO2 Max. Now, when you want to get a sense of what certain activities look like. And again, so much of what we talked about on this podcast, even what we've already gone through, like I glossed over some of the details of the benefits of exercise in the show notes, we will include so much on that. So that if you really want to go deep on every single aspect of healthspan and lifespan and the mechanism for each, we've got all, all of that in great references. But again, when you want to think about how many mets do you get doing various things? Well, again, sitting there doing nothing is one Met walking your dog might be three Mets. Going for a slow bike ride, kind of ten miles an hour or less. Four Mets. Mowing your lawn might be five and a half Mets playing golf four and a half Mets. Resistance training vigorously six Mets. So you kind of get a sense. Now where does this go? Well, rowing at 100 watts, which really isn't that much of a killer effort, you're at 7 watts. Pardon me, at 7 Mets. Now you can look at the speed change, right? So once you're running six miles an hour, just a 10 minute mile and that's still a jog, you're almost at 10 Mets at that point. Once you're running 10 miles an hour, 6 minute mile, this is a pace that a fit person can hold for a while, but most people couldn't hold for very long. You're at about 14 and a half Mets. So you get the sense of the non linearity of this. Meaning 14 Mets versus 7 Mets. You wouldn't hold 7 Mets for, or you wouldn't hold 14 Mets for half the time.

You'd hold 7 Mets just to double click on it. Mets, you get per activity as per an hour of activity.

No, it's all normalized per time. So if you're running a six minute mile pace for an hour, we would say you did 14 and a half met hours of work. So here's the way to think about it. It's the difference between watts and joules. If you think about if anyone who's a cyclist will think of things that way on a bike. Your power meter tells you instantaneously how much work you're doing. That's wattage, which is really joules per second. And then you multiply that over the total time that you do it. You take it back to total energy. So the met is an instantaneous measurement and you normalize it over time to give the total volume. So the work that's done is really the MET hour. So for example, if you, I don't know, do a hike for 6 METs worth of activity or 6 METs worth of exertion, and you do it for 45 minutes, that would be 4 MET.

Hours of work done.

Peter, when people think about their Mets, how is it that knowing how many MET hours you're putting out, how is that helpful to someone as they think about exercise on a whole?

You know, look, I think for most people it's not. Truthfully, I'm probably one of the few people who tracks my met hours per week. I don't do it down to the nat's ass. I just mean I have a spreadsheet where I'm basically putting in my activity the amount of time I spend doing it at various different intensities. And I can at the end of the week say, look, I'm doing a hundred MET hours per week during this phase of my training. During this phase of my training, it might be 80. Back in the old days, it was 200 met hours per week. It was a much greater workload. If you're doing one thing that's tied to a power meter, like in cycling, you know, we tend to keep track of kilojoules and normalize power and power. So. So all of these things are just sort of ways to track the work you're doing. Now, I think it partially becomes relevant when you want to evaluate the research because the research has to be able to take into account not just how much time you're exercising, but what's the intensity of that exercise. It would be very difficult to provide guidance if we didn't know this. For example, do we want to say just the amount of distance you run a week tells us everything we need to know. Are two people who are running 15 miles per week experiencing the same metabolic benefit or harm? Well, certainly not. One could be running them all at 10 minute mile pace. One might be. I mean, just imagining this, one might be running them all as 400 all out repeats. So you have to have some way to kind of normalize that. And in the case of the latter, you would probably see a much higher met hour because of the intensity.

And so with that kind of background, now we're going to kind of get to the core of what we get asked about. And so the first question is, to the best of our knowledge, are we even able to say if there is a minimum, efficient or most effective dose of exercise when you look at med hours per week, is that something that. Is that our understanding?

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Sam.