LS 71 - Fast Exercise with Dr. Michael Mosley
10 Aug 2016 · 19 min
In this episode of the Longevity Show, host Jason Hartman interviews Dr. Michael Mosley, a science journalist and author of Fast and The Fast Diet. Mosley explains the science and practical application of high‑intensity interval training (HIIT), which he calls “fast exercise.” He argues that short, 20‑second bursts performed three to four times a week, with a work‑to‑rest ratio of roughly 1:1, tap into an evolutionary pattern of sprinting seen in hunter‑gatherers and animals. At the cellular level, these bursts boost mitochondrial efficiency, improve fat oxidation, and enhance insulin sensitivity, offering a time‑efficient way to improve metabolic health. Mosley cites historical research (Gerhardt’s 1930s sprint protocol) and modern university studies showing rapid improvements in heart volume and cardiovascular fitness, even in sedentary or diabetic individuals. He outlines how to integrate fast exercise with strength days, recommends stair or hill sprints, and stresses the need for at least one recovery day per week. The conversation then shifts to Mosley’s Fast Diet (5:2 intermittent fasting), which mirrors the “burst‑then‑rest” concept for nutrition, reducing calorie intake two days a week to improve insulin sensitivity and lower disease risk. Finally, Mosley discusses his documentary Living With Parasites, describing his self‑infection with a benign beef tapeworm to explore how parasites modulate appetite, weight, and immune responses, and to raise public interest in parasitology. Throughout, Mosley provides URLs for his books and websites, encouraging listeners to adopt fast exercise, fast diet, and to learn more about parasites.
Chapters
This show is produced by the Hartman Media Company. For more information and links to all our great podcasts, visit hartmanmedia.com.
Welcome to the Longevity Show. Informing listeners on the important aspects of health, wealth and happiness to ensure you live life to its fullest. With fascinating interviews with top authors and gurus in the field, along with the latest news in the science and technology of longevity, we're going to reveal expert advice and amazing secrets of living a longer. And now, here's your host, Jason Hartman.
It's my pleasure to welcome Dr. Michael Mosley to the show. He is a science journalist and executive producer at BBC, author of Fast the Simple Secret of High Intensity Training. Michael, welcome. How are you?
I'm very good, thank you.
Well, good, good. And you're coming to us from London, England today, right?
That's right. And the sun is shining and the blossom is out.
Well, that's kind of rare there. So glad to hear in the city where it rains a lot. Tell us about your book and your philosophy of exercise. I mean, I'm familiar with interval training and I see how it really. It just sets up your metabolism for good things, doesn't it?
It does indeed. I mean, this is based on a lot of scientific research, and the exercise physiologists, the sports scientists, are coming around to the view that when it comes to exercise, less can be more, that it's about the intensity with which you do it rather than the amount of you spend doing it. And that's really quite good news for a lot of us who are time poor or who are reluctant to go out for long runs. So I got into this about two years ago. You talked about interval training. Now, many people, when they hear the word high intensity training, they're terrified they're going to have to spend five minutes bursting their guts out or something like that. In fact, the regime that I talk about consists of doing short bursts of 20 seconds and really no more than three or four of them in a given day, and probably no more than three times a week. So it is a very small commitment of time, but it does have some very big effects.
You know, this is interesting. I want to ask you why it works, but I try to think of most things from an evolutionary perspective. And, you know, if we were living in caves and we had to run away from a predator, we wouldn't run 26.2 miles. We would sprint a couple hundred yards, probably. Right, exactly. And maybe that's what we were designed to do. Certainly that's the way my dog is designed. I mean, my Dog can run incredibly fast, but gets tired pretty quick. And it's an interval trainer is the way the animal works, at least.
Exactly. And that's when you watch children do things. That's what they do. They have little birth and then they stop. This is precisely the thinking behind it. And I could have equally called it the caveman or cave woman workout diet.
It's the paleo.
A paleo workout, indeed. Because when they studied hunter gatherers, people like the Hadza who live in Tanzania, that's what they do. They spend quite a lot of the day kind of loafing around. They do a reasonable amount of walking, at least. Men do. They typically do about 10 kilometers a day, about six miles, women slightly less. But they do have these sort of short burst intervals of running, which may be 20 seconds, 30 seconds, flat out, either to avoid being eaten or to catch something. And they also do a little bit of strength training during the day, though they wouldn't call it that. Chopping down trees or something, which basically gets those muscles going. So that's kind of the evolutionary argument. And indeed, a while ago I wrote a book called the Fast Diet, which suggested that the way we eat is we should also have these bursts of food and famine. That one proved to be spectacularly successful around the world as a book. Now, this pursues a similar sort of idea that it's about short bursts of intermittent stuff going on. And that seems to be how our bodies work. And at a molecular level, what we know that happens is that when you do these short, short bursts of intermittent training, they produce more efficient mitochondria. These are like little power cells in your muscles. And what they do is they convert fat and sugar into energy. And the more you have, and the better working they are, the more power you will produce, but also the more fat you will burn throughout the day, not just when you're exercising, but in the hours after that. So that's one of the things that intermittent training absolutely seems to do far more effectively than kind of just your standard jogging or strolling. It produces more of these mitochondria, and that seems to be absolutely key to how it works.
It's really interesting. I mean, what is the speculation as to why it works this way or what is the actual science? I mean, if we know, why does this work? And then I've got a question for you more specifically on how to interval train properly.
Absolutely. As I said, I think there is evolutionary reasons why this has happened. Most people, they don't know, they know it to be true and they are equally perplexed and surprised because I was astonished when I first started doing this because I met up with a professor and he said to me, I can change you, I can make you healthier, I can make your lungs and heart stronger and I can improve your metabolic fitness. That's your ability to metabolize sugar in just one minute of high intensity training done three times a week, in four weeks you'll see change. And I said, that is impossible. But he said, give me one minute. So what I would do is I would get on my exercise bike, I'd have a little bit of a warm up, then sprint for 20 seconds against resistance. A bit of a breather, 20 seconds. Bit of a breather, 20 seconds. Now that is one minute of hard exercise, though if you put in the breather, then it probably adds up to about three or four minutes in total. And I did that three times a week and I did it for four weeks. And at the end of that time there had been really big changes. I was completely gobsmacked. But he said, that's what we found. We've done lots of studies on this. We know it to be true. We don't entirely understand why it's true, but there are probably about 15 universities around the world at this moment studying this. They're really looking to see how you can get the most out of the least amount of time. Because people have been dishing out advice saying, go and do 60 minutes, whatever, 90 minutes a week, and people just don't do it. Less than 20% of Americans follow the advice. So what these scientists are doing is saying, okay, if we can't persuade people to go and do that, maybe we can persuade people to do this. And anyway, it seems to be more effective. So that was kind of the thinking behind it.
Yeah, I went to an executive health screening several months ago and spent a full day there. That was very enlightening to do that. I'd never done it before. They said, get your heart rate up to about 162, I think it was, and then let it drop to about 125. And as soon as it drops to 125, then get it up to 162 again and do that about five times.
Absolutely.
And the thing is, though, it's different than a little bit different than what you're saying, I think because it takes more than 20 seconds for that to happen. I don't know if I can get it up to 162 that fast. I can't remember. I am using a Heart rate monitor.
But indeed one of the things you'll find is that in the first burst of 20 seconds it will not go up there. It'll probably go up to about 125, maybe 130. The second time you do it it will be up to about 160. The third time you do it will probably be up to about 180. Now the guy who did this originally, he did it about nearly 90 years ago, a guy called Gerhardt. And what he did is he took sprinters and he asked them to sprint for 200 meters pretty well, flat out pushing their heart rate up to about and they would do it for about 20, 25 seconds and their heart rates would go up to about 170, 180. Then he asked it to wait there until it dropped to 120 and he did it again. Now he did that probably more frequently than even four or five times, but these guys were really fit. Now the guys he trained, two of them went on to become Olympic gold medal runners. What is different is these techniques have developed over time and it's no longer just confined to top athletes. They're now using it for people who are more sedentary, people who are middle aged, people who are diabetic, people who are overweight. The principles are still the same. What Gerhardt found is just by doing this he could increase the heart volume by 20% in a six week period, which was unbelievable.
That is unbelievable.
But he turned out to be true. There is something about these intervals that does it and there is something about pushing the heart rate up. Now the reason that I'm advocating 20 seconds and indeed because that's what the research shows and the reason they've gone for that is it seems to be safer than pushing yourself for longer. There's these other things out there, like the insanity workout, you know where people do it for like three or four minutes but actually you have to be insanely fit to start with. So this is kind of a more gradual process. You are getting your heart rate up there, but you're getting it up there in stages rather than expecting to do it in one go. And the heart seems to respond better to that. So that's the only thing I would say, I would say what I'm doing is actually better, it is safer, it is more science based.
Right. Tell you, you know the old saying, a picture says a thousand words. If you think that the picture is meaningful, all you have to do just go online and search a photograph of an Olympic sprinter versus a marathon Runner. And you tell me which one looks healthier.
Yes, indeed. Absolutely.
It really is. Well, let's switch the conversation just for the brief time we have left, and let's talk about parasites for a moment. You are also the author or a presenter? I'm not sure if it's a book or. I think it's a book. Right. Living With Parasites.
It's a documentary I made recently.
Okay, fantastic. Well, you did an amazing thing on that documentary where you infected yourself with a load of gruesome parasites by swallowing tapeworms to see how they affect the human body. I guess I'm assuming you couldn't get any government to do a clinical trial on this, so you had to do it yourself. Right.
Well, there are actually a couple of trials going on at the moment, but I couldn't take part in them, so I thought it would be interesting to try this. What I did, actually, is I went.
I want to say thank you for taking one for the team, but tell us what happened.
I actually took three for the team. In the end, I went off to Kenya and we found some. I decided to get infected with something called a beef tapeworm. Because it is relatively benign. It only infects humans and cattle. So I got my wife's approval. She's a doctor. She just wanted to make sure it was safe before I went off and brought something horribly infectious back. And I went off to Kenya. We found some infected meat, cut off the tongue, removed the cysts, and I swallowed three of them. And then I wanted to see what happened. And Interestingly, for about eight to 10 weeks, I didn't really notice the difference at all. I had no idea if I was infected or not. It was only when I swallowed a little pill cam, which takes pictures, that I actually saw the tapeworm for the first time. And if you actually Google my name and tapeworm, then you'll see some sensational pictures of the tapeworm inside my guts.
What were the consequences of this?
Well, actually, one of the consequences was that I put on a small amount of weight, because I think what happens is the parasite was actually manipulating my appetite. It made me more inclined to eat, particularly carbohydrates. I was interested to see what effect it would have on my immune system because there is quite a lot of research which suggests that parasites can dampen your immune system in quite useful ways, particularly if you have allergic diseases like hay fever or asthma. And I have mild hay fever. So I wanted to see whether it might improve that because there have been studies which suggest that infestation with parasites will do that. And it has a small effect, but nothing terribly big. But it was just kind of an interesting exercise.
Right, right. I'm looking at these pictures now. They're kind of gross, but I do recommend people Google that, as you mentioned. What was the point of that? What do we need to know about parasites?
I think the parasites are fantastically interesting. They are the most successful life form on the planet. They're probably the most common life form on the planet. Every creature on Earth has several parasites. We probably have about 70 or 80 different parasites that infect humans. And we understand very little about them at the moment. So it's really trying to encourage an interest in parasitology because they are this fantastically interesting life form. They manipulate us in ways we barely understand. And modern science is beginning to appreciate that there are upsides as well as downsides to being infected with parasites. And they want to find out more.
Very interesting. Is there anything else you want to talk about before you go? The fast diet.
Yes, the fast diet is something that I feel very passionate about because my particular passion is diabetes. My dad died of diabetes at the age of 72. And two years ago I went off and had some bloods done and I was told that I was basically a type 2 diabetic, that my blood sugar was way too high. That's what got me started on fast exercises because it improves your insulin sensitivity. But it also got me going on the fast diet, the idea that if you do a pattern of intermittent fasting, a feast and famine approach, that will improve your insulin sensitivity and cut your risk of diabetes. I wrote the book, it became an international best seller. But I just want more people to know about it because since I wrote the book, there have been so many more studies, particularly studies done by people involved in the field of diabetes research, all of which show that this is really a fantastically interesting way forward for treating what is a really common disease and which is on the increase worldwide, but particularly in places like the States and the uk.
Is this like interval training with food?
Yes. Basically what you do is you eat normally five days a week, and then two days a week, you cut your calories to about a quarter. And surprisingly enough, if you do that, you will lose a lot more fat than you would on a conventional diet. But importantly, it also seems to improve your insulin sensitivity. So your body needs to produce less insulin to get rid of the sugar in your blood. And that's good because high levels of insulin are associated with increased risk of diabetes, dementia, and common cancers like breast Cancer and prostate cancer. So you want to keep your insulin levels down. You can do it by intermittent fasting, but you can also do it by doing high intensity training. Both of them are really effective.
Let me ask you one more question about working out. I mean, we talked about in the beginning, we were talking about interval training. Is there a certain ratio? It seems like you're very interested in these ratios. The fast Diet is the 5 and 2 ratio. Ratio is 20 seconds and then rest. And by the way, back to the interval training, how long should it take to Recover between the 20 seconds? It's 20 seconds.
Aim probably for a minute or two. You probably need longer to start with. In the end, you're trying to aim for a ratio of one to one. So when you're super fit, you probably do 20 seconds on, 20 seconds off, 20 seconds on, 20 seconds off. And you'll manage six or seven of those. When you start out, you will find yourself struggling to even complete one against high resistance. And so I suggest you kind of build up over time. And yes, there is something that seems to be fantastically important about getting the ratios right. And that's what I write about quite a lot in the book.
Sure, sure. With that is the only way we can really spike that heart rate enough for 20 seconds. Is it really running? Is it all about running? Or can you do it with weightlifting, for example, or is it just.
You can do it pretty well? Any way that gets your heart rate up, I mean, one of the most effective ways is to run upstairs. Because when you run upstairs, gravity is doing a lot of the work holding you down. You'll burn three times as many calories running up the stairs as you will on the flat. And you will find your heart begins to pump. If you're really unfit, then start off by walking up the stairs. You know, some people haven't even walked up the stairs for years. But if you do sort of 25, 30 seconds of stair running, you'll feel it and I can assure you your heart rate will shoot up.
What about just running uphill? A lot of wind sprinters do that.
Anything which basically increases resistance. So running up hills is good. My wife is a doctor. She goes out regularly jogging. She goes to the nearest hill. She used to just kind of jog at a steady pace. Now what she does is she jogs off to the hill, which kind of warms her up. And then she sprints up the hill, walks down the hill, sprints up the hill. She does sort of three lots of short sprints and then she Comes home and she said that just improved her fitness no end.
Okay, so the ratio I wanted to ask you about before you go is in terms of days. Should we be doing that interval workout every single day, seven days a week? Should we rest like God did?
You need a recovery day? You need at least one day a week. When you're not doing any of this stuff, what the research suggests is it's best to alternate. So I write about it in the book. It's basically one day you're doing what I call fast fitness, which is these short bursts. The next day you're doing strength exercises, which are press ups, squats, things like that. And then you go back to the fast fitness ones. So you're giving your body different things to do. Your body needs recovery time. There are lots of really sophisticated biochemical processes going on that get stirred up by doing it. And so ideally what you want to do is do different pathways, do different stuff.
Definitely. Okay, good, good. Well, that's great to know. The entire fast workout. How long does it take? I mean, can we spend a lot less time in the gym?
Oh, absolutely. Because the great thing is you don't have to go to the gym. I mean, normally it takes you a while to get there, get undressed, change, do the thing, come back. No, you can do all this at home. You can do it in your bedroom. It's going to take you a maximum of about five or six minutes.
This is just joy to my ears and probably a lot of people listening. I love it. Well, that's fantastic. Give out your websites, if you would, and tell people where they can learn more about this.
Absolutely. You can buy the book, the Fast Diet and also the Fast Exercise at Amazon and any decent bookshop. I've got two websites. One is called thefastdiet.co.uk where there's a big sort of support group. And the other one is called fast-exercises.com fantastic.
Well, Dr. Michael Moseley, thank you so much for joining us today.
Thank you.
This show is produced by the Hartman Media Company. All rights reserved. For distribution or publication rights and media interviews, please visit www.hartmanmedia.com or email mediaartmanmedia.com Nothing on this show should be considered specific personal or professional advice. Please consult an appropriate tax, legal, real estate or business professional for individualized advice. Opinions of guests are their own and the host is acting on behalf of Platinum Properties Investor Network, Inc. Exclusively.
More from Jason


2482: AI Labor Displacement and the K-Shaped Housing Affordability: High-End Housing and the New Economic Divide with Adam Taggart


2482: AI Labor Displacement and the K-Shaped Housing Affordability: High-End Housing and the New Economic Divide with Adam Taggart


2480 FBF: Investor Mindset & DuckDuckGo Founder, Super Thinking Mental Models & Traction, How Any Startup Explosive Growth by Gabriel Weinberg


2480 FBF: Investor Mindset & DuckDuckGo Founder, Super Thinking Mental Models & Traction, How Any Startup Explosive Growth by Gabriel Weinberg


2478 FBF: Jim Rickards on The Death of Money, Aftermath, Currency Wars & The New Great Depression


2478 FBF: Jim Rickards on The Death of Money, Aftermath, Currency Wars & The New Great Depression


2477: Builder Profit Margins Hit 26-Year Lows and Solving the American Housing Crisis

