Why have we evolved to avoid exercise? With Harvard Professor Daniel Lieberman (E263)

0:00Watch it early on the High Performance App. Available now, Roman Kemp, the broadcaster, opens up a powerful conversation on success and mental health. 75 % of the time when somebody walks into a doctor's office, it's for a disease that's technically classified as preventable. We're mismatched to being inactive. Our bodies never evolved to be inactive. We evolved to avoid physical activity when it wasn't necessary or wasn't rewarded. We shouldn't blame and shame people for struggling to exercise. They're just completely normal human beings doing what we have all to do. That is the incredible Dan Lieberman.

0:41And this is High Performance, the show that unlocks the minds of the most fascinating people on the planet. I'm Jake Humphrey. And on this show, we learn from the stories, struggles and successes of our guests, allowing us all to find our own version of High Performance. And today we talk about the story of human evolution with Dan Lieberman, who is a paleoanthropologist at Harvard University. If you don't even know what that means, all you need to know is that you are not a product of your upbringing. You are not just as old as you are today. You are part of the evolution of the human species.

1:17And Dan is an expert in this. In fact, he wrote an incredible book called Exercised, which really lays bare the things that we should be doing today based not on who we are today, but on what we've evolved from. Honestly, this is such a fascinating conversation. So let's get to it and welcome the incredible Dan Lieberman to High Performance. However, first, a few key messages from our valued partners, allowing us to offer you this content for free. Before we get going, just to let you know that you can now enjoy a free trial of High Performance Plus. where you can get early access, ad-free content, exclusive masterclasses, and high-performance originals.

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3:45Well, Dan, thank you very much for joining us. My pleasure. What is your definition of high performance? Well, I study how and why humans evolved to be physically active. So I think instead of focusing on elite athletes and people who win stuff, I'm actually just interested in how and why average everyday people can do really quite remarkable, decent physical activity. So it doesn't have to be running a marathon, although pretty much anybody can if they train. So for me, high performance is really just about achieving your goals and just staying fit, staying active. And why is it important for us to have this kind of conversation?

4:27Because we're in a world where machines have replaced human labor. And for millions and millions of years, our ancestors had to be physically active in order to survive. And that's woven into our biology. And now we have to choose to be physically active. We have to do this weird thing called exercise, which is to be engaged in discretionary, voluntary physical activity for the sake of health and fitness, which nobody did until very recently. But it's important for health. So we now have to find ways to encourage each other and help each other stay active so that we can stay healthy. And I'm well aware that people that are tuning into this have got a myriad of podcasts to listen to.

5:08hundreds of social media accounts based on fitness and health and trying to find your own optimum performance um i hate i bet you do i thought you might there's a lot of misinformation out there there's a lot of challenges for people so where is the best place for us to start i guess it's not regarding optimum performance uh but where's the the best place for us to begin this conversation that would carry most value you think to to our audience well maybe let's start with the the basic epidemiological evidence, right? So large-scale studies of millions of people, right, in America, England, elsewhere, which show that just a moderate amount of physical activity, just 150 minutes a week, which boils down to 21 minutes a day, lowers your all-cause risk of death at a given age by approximately 30%, which is massive, right?

6:01Nothing. There is no thing you can do that has as much benefit. And of course, if you do more, you get yet more benefit. Of course, it tails off at a certain point. So just even a moderate amount of physical activity, doesn't have to be running the London Marathon or whatever, just a moderate amount of physical activity has enormous benefits for physical and also mental health. I think that's probably the most important thing that everybody needs to notice. And just a little bit is better than none. I get another of fact, breast cancer, right? You know, a concern that we all have, colon cancer.

6:36You can lower an average person who exercises something like, you know, 150 minutes a week, right? Just going for a brisk walk can lower their lifetime risk of breast or colon cancer by somewhere between 30 and 60 % depending upon which study you're looking at. I mean, that's massive, right? You can lower your risk of Alzheimer's by 40 to 50 percent, heart disease, diabetes, all these chronic diseases that cost lives and money and misery. Just moderate levels of physical activity have enormous benefits. And so I think that's the place to start. We never evolved not to be active, and we pay a huge price for being persistently sedentary.

7:20So why are we persistently sedentary? because it feels to me like you hear that said once by you. And that should be on the front page of every newspaper. It should be the first story on every news bulletin in the evening. It's like we're all looking to live longer and be healthier. Here's an answer. Yet it seems a real challenge for people to do it. Well, so the reason why I called my book Exercised is that we make people exercised about exercise. We make them anxious and whatever. Because we tell people if they don't exercise, there's something wrong with them, right? They're lazy. They're deficient in some way.

7:54But the important thing to realize, again, is that, remember, exercise is this discretionary, voluntary physical activity for the sake of health and fitness that we never evolved to do. Because for millions of years, I mean, literally millions of years until just a few generations ago in places like the UK or the US, and still for many people around the world, people have to be very physically active. But they're also struggling to get enough food. They're struggling to get enough energy. And when you're struggling to get enough calories because you're working very hard to get enough to feed yourself and your family, going, like I went for a five mile run this morning around Regent's Park.

8:33I spent about 500 calories doing that run. That would have been a completely stupid thing to do if I was struggling to get enough food, right? That's energy that I couldn't spend on helping my family. so we evolved to avoid physical activity when it wasn't necessary or wasn't rewarding right that's a fundamental adaptation so you know i always talk about when you go to a you know a an airport or a tube stop or whatever and there's an escalator and a stairway right it's even though there were no escalators in the paleolithic right it's an instinct to take the escalator because it saves energy well i know i came here today i knew i was talking to you so i at the stairs.

9:15I was the only person on the stairs and hundreds of people flooding past me going up the escalator. But we know this now, though. We know that it's better to take the stairs. So why am I the only one on the stairs? But we have two parts of our brain, right? I don't know if you've read Daniel Kahneman's famous book, Thinking Fast, Thinking Slow. But, you know, I mean, he's not the only person to argue this, but, you know, we have instincts to save energy, right? It's like, just like you have instincts to, you put chocolate cake in front of me, I'm going to, it's my instinct to go for the chocolate cake instead of the carrot, right?

9:46There's also a carrot. So we have to use our slow brain to override our fast brain. We have to consciously make that decision, which is what you just told me, right? You thought about, oh, you're meeting this exercise freak, so I better take the stairs. And I'm the same way. And my office is on the fifth floor of a beautiful Victorian building at Harvard. It's quite a climb to get up to my floor. And if I take the elevator, I guess you call it the lift here, right? I'd be called a hypocrite. So I have no choice. I have to take the stairs because of what I study. But every day I have this little debate with myself and I have to override my instinct to take the lift because it's better for me to take the stairs for, not just for my health, but also for my reputation.

10:33So it's just natural, right? And so we live in a world now where we no longer have to be physically active. And also a lot of the physical activity that people do isn't much fun. I mean, it's not fun to trudge up the stairs and that Chancery Lane tube stop or whatever. So, you know, or it's not, you know, getting on a treadmill, right? Which is what a lot of people do, right? I mean, who enjoys running on a treadmill? Nobody. I mean, you can make the time pass if you're maybe listening to this podcast or something like that. But so we, you know, we make it often very unfun. And we certainly make it unnecessary.

11:09And the result is that people are just normal. So we shouldn't blame and shame people for struggling to exercise. They're just normal, absolutely completely normal human beings being doing what we have all to do. So what does someone like you do differently then that means you get up and go for a run today? How have you got yourself to that place? Because I'm sure there are people are going, great, I now know what I need to do, but my brain is still going to tell me why bother. Well, I struggle just like everybody else. There's nothing special about me. So I find ways to make it either necessary or fun.

11:42So I sign up for races. Like I have a race coming up on April 15th and I don't train, I don't humiliate myself. So I better, so that's why I'm like, you know, here I am traveling and I'm still running around, you know, various places to try to stay fit. I also run with friends when I can. so I arranged to meet friends and then it's a social thing so we meet at a certain place and if I'm late they're going to be irritated at me and vice versa so we kind of coerce each other socially to do it and then of course it's often early in the morning we're kind of grumpy and whatever but by the end of the run we're usually chatting and gossiping and having a good time and usually I'm glad I did it so make it fun rather than a necessity I also love reading about the way that you talk about nudges and shoves.

12:30Can we talk about those? Sure. I mean, you know, there's, look, we can coerce people, right? Yeah. And that's what we do in school, right? I mean, children are required to do sports or some other kind of, you know, exercise. And, you know, we think that's okay, right? Because children can't make decisions for themselves. But for adults, you know, we're not, you know, you can't tell me what to do. I'm an adult, right? So what we need are help that we would agree to. So help us help ourselves. And so we call those nudges. So putting the lift or the escalator kind of out of the way so that it's easier to take the stairs rather than the escalator.

13:21That's a nudge, for example. or incentives or whatever. There are many forms of nudges and we don't really use them very often. But we can and should use them more. And I think that gives people choice without coercion and helps them do what they would actually like to do themselves. What about a shove? Shoves are just like hard nudges, right? Okay. Let me think. I mean, a shove might be, let's say your boss signs the entire team up for, you know, the, you know, the, the counting team or whatever it is you, you do for some kind of, you know, race, right? To raise money for a charity, right? And then it's like, you're not, you're not going to be the only one who's not going to go participate, right?

14:10So you're kind of, you're kind of forced to do it, right? in a kind of a socially, you know, and maybe people do object to that sometimes, but that can be useful. So in the book, one of the things I did is I went to the Bjorn Borg company in Stockholm because it's, as far as I know, still the only company in the world that requires all of its employees to exercise. The CEO is this exercise fanatic. And as far as he's concerned, And if you want to work at his company on Fridays, it's, you know, fitness hour or sports hour, I can't remember what they call it. And the entire company, it doesn't matter who you are, you could be a board member, you could be somebody who sorts the mail, you could be the CEO.

14:53Everybody goes and exercises together. And if you're visiting, you go too. And that's quite a shove. And do you agree with it? Well, you know, I was kind of curious about it. So I emailed the company and said, can I come and see this? Because I was curious about it. And they invited me to go. And he said, and I was given free reign to the company. I could talk to anybody I wanted. There was like nobody minding me or watching me, listening to me, etc. And the vast majority of folks said, there were a few, of course, who were just like, you know, exercise fanatics already. And they loved the fact that everybody did this together.

15:28But there were some who also, you know, did it a little bit begrudgingly, but were kind of glad that they did it. And there's some who, they told me, people who quit, you know, when the company started doing this, there are people who had left the company because they're like, I'm not doing this. So, but I think for the most part, so the people who are still there appreciated it. They realized it was a good thing, you know, because it, you know, when you exercise together, you not only get the benefits of exercise, you also, it's like a, it's a communal thing. You're having fun. It's like, look, there are forms of physical activity, which we don't always call all exercise physical activity, but that are communal, that every culture has done for millions of years, like dancing.

16:12And we've kind of stopped doing that in our culture, right? We just don't do that anymore. Can you explain what actually physiologically happens to our bodies? Because I love these numbers. You know, if you do exercise, you lower your risk of all-cause death by a huge amount. But I still don't really understand why. Like, what's actually happening to us? so there are two ways in which exercise or let's call it physical activity because it can be working in the garden right which is most people don't consider exercise or going for a dance right but there are two ways in which physical activity are beneficial so and they all have to do with energy right so the first is that when i'm spending energy on physical activity my body is is allocating energy to that activity as opposed to other ways my body can spend energy which are unhealthy right so one of them is adding too much fat right yeah so fat is normal right we all need fat fat is fat is sometimes unfairly demonized um and humans are unusually fat creatures so most animals have about four percent five percent body fat we evolved to have three to five times that skinny people have three to five times more body fat than our closest relatives who are primates or most mammals.

17:28But if you're... And the reason fat is important for humans is that it's important for reproduction. We need fat to help make sure our brains always have energy. It's like money in the bank. We need to have fat to pay for our reproductive strategies. We need to have fat for all kinds of important reasons that it's been selected for in human evolution. So our bodies, unlike that of many other animals, or more so than other animals, whenever there's any extra energy, it goes into fat. So that's one of the reasons why exercise or physical activity is so incredibly useful for preventing weight gain or weight regain.

18:06It's not great for losing weight, but it's phenomenal for preventing you from gaining weight. So exercise should always be a part of any dieting strategy. The other thing that exercise does or physical activity does is it affects hormone levels. So remember, what does natural selection care about? Reproduction. Exactly. How many babies you have, right? So when we stop being physically active, our bodies say, oh, there's extra energy. And hormone levels go up, especially in women. And in the second half of the menstrual cycle, what's called the luteal phase of the menstrual cycle, estrogen rises and especially progesterone rises.

18:48and those hormones um and they rise to unusually high levels levels that aren't necessary to get fertile right to get to get pregnant those those higher hormone levels are what cause the higher levels of breast cancer in in women right because because again if you have all this extra energy plow it into reproduction i think that's fascinating because i think that we all associate eating food with more fat and then the more fat makes you iller but actually what you're saying is the eating of the food gives you this kind of the opposite of a calorie deficit, whatever that word is. You'll probably know that rather than me.

19:23But you've got all these extra calories, all this extra energy, and your body's then increasing hormones in women, which is then... Well, it's not just eating food. It's also not being physically active, right? So both of them affect what we call energy balance. You can be either a positive energy balance, which is you're gaining weight, or a negative energy balance, you're losing weight. Most of us manage to, you know, we're cycling back and forth and bike and forth. we stay pretty stable. When you're not spending energy on physical activity, again, I spent 500 calories this morning running around Regent's Park for no reason whatsoever, right?

19:54That's energy. If I ate the same amount of food, I would just plow that into fat. I'm not female, so I wouldn't increase my progesterone levels, right? But anyway, but the point is that both of those are unhealthy, right? Too much fat causes inflammation. And inflammation is what causes pretty much every disease that most of us are concerned about. It causes heart disease. It causes diabetes, type 2 diabetes. It affects cancer rates. It affects Alzheimer's. It affects arthritis. I mean, the list is long and very, very, very scary, right? So too much fat, and we can talk about why that's the case, but it becomes inflammatory, and inflammation just mucks up our body.

20:34And also levels of hormones that are too high increase rates of cancer. So that's one. That's one pathway. which exercise is good but the other one and is that when when i go for a run or you place you know game of football or whatever it is that you do right you're stressing your body right you're causing physiological stress pretty much in every system of your body you're you're causing you know your mitochondria which are the little organelles in every cell that provide the energy right they're like the battery packs of every cell right those mitochondria as they produce energy they're just spewing out what we call reactive oxygen species.

21:11Those are molecules that have unpaired electrons and they're highly reactive. They cause basically, you know, when your apple browns, if you just let it sit there, that's the same thing. It's oxidation of tissue, right? So those little reactive oxygen species cause damage everywhere, right? So exercise actually creates this sort of storm of really unhealthy molecules that are just flooding your body, right? It causes DNA damage. It causes proteins to become what we call glycated. They get damaged by heat and by sugar to start attaching to them and gum them up. You create tears in your muscles.

21:54You create cracks in your bone. I could go on, right? I mean, every single system of your body pretty much is affected by, is stressed by exercise. But our bodies also evolved to cope with that, right? So when we produce these reactive oxygen species, our cells produce antioxidants that mop that up. Our cells produce enzymes that repair our DNA, right? And keep the chromosomes from getting shortened and repair our muscles and repair our bones and keep our brains healthy. there are a gazillion of these proteins that we produce. And because, well, two important things. One is that because we never evolved not to be physically active, we never evolved to turn these mechanisms on in the absence of physical activity as much.

22:46And then secondly, they always overshoot, right? Because you don't want to, I mean, if you created all this stuff and you didn't mop up all the damage, you'd die younger if you were physically active, right? And we know that's not the case, right? So I often say it's like spilling coffee, right? You know, if I were to spill coffee on this table and then I cleaned it up, right? The table would actually be cleaner than before I spilled the coffee. Not that the table looks all that dirty, right? And it's the same thing in your body, right? You overshoot the damage repair. And the result is that you have maintenance and repair and also remodeling that, you know, repair your DNA and keep your chromosomes from getting too short and keep your muscles from atrophying.

23:29And the list goes on forever. Your brain, the neurons in your brain from getting clogged up. We produce a factor called BDNF, brain-derived neurotropic factor. It's actually produced by your muscles in vast quantities when you're exercising, when you're physically active. What does that do? It's like a colleague of mine calls it miracle grow for the brain. It's what actually causes new neurons to grow in the brain. And it actually repairs and keeps the synapses in your brain from getting damaged. It's probably one of the major reasons why exercise is by far an order of magnitude more potent for preventing Alzheimer's and dementia than any other known thing you could possibly do in your life.

24:11Because you're producing these molecules that help you. Another thing that we study in my lab is a molecule called IL-6, interleukin-6. We all heard about this during COVID, right? Remember the cytokine storm? So cytokines are molecules that turn on your immune system, right? So it turns out that we always knew that these molecules were produced by our blood cells, our white blood cells, you know, but they're also actually produced by your muscle. And when you're active, and I have a lot more muscle in my body than I have white blood cells. So when I go for that run in the morning, I produce this prodigious quantity of IL-6, which at low levels is inflammatory, but at high levels turns off inflammation.

24:53So that's one of the reasons why people who exercise have lower levels of inflammation because their muscles are shutting down that system, keeping us from getting damaged. So there's a gazillion repair and maintenance and remodeling mechanisms that are incredibly beneficial because we evolved to be physically active, but we don't turn them on in the absence of physical activity because we never evolved not to be physically active. There was no time in human history until very recently when you could just sit around all day in a chair and just do nothing. You had to go out and be active. The average hunter-gatherer walks 9 to 15 kilometers every single day.

25:32Every single day. There's no holidays. There's no weekends. There's no retirement. To put it into practical terms, a typical hunter-gatherer would walk from Los Angeles to New York City every year. So we've got a body designed for a very different world. That's right. So we call this a mismatch. We're mismatched to being inactive. Our bodies never evolved to be inactive. And so as a result, we don't turn on all these mechanisms that keep us healthy. And so what we do is we get sick if we're inactive, and we go to the doctor, and we get pills and various other sorts of treatments to keep us going.

26:11But what exercise does is it increases what we call your health span, the years that you live without any disease or disability. So people today are living longer than before, that's for sure. Although not that much longer, actually, than Hunter Gathers. But they're also living more and more years with disabilities. The average American now lives to be 78, but the last 16 years of their lives are spent on average, this is average, so many people have more, with some serious kind of chronic disability. And most of those disabilities would be prevented to some extent, if not to a large extent by having been more physically active earlier in their lives.

26:52I guess one of the toughest challenges, right, is that I'm 45. So if I listen to this conversation, I probably think, well, my knees are a bit sore. I can't bounce out of bed like I used to. I can't play on the play area with the kids like I could when they were first born seven or eight years ago. But apart from that, I'm okay. I mean, what we're really asking people to do, which I guess is a challenge, is to do the work now with the rewards in the future. To some extent, yes. So you're doing what we call hyperbolic discounting, right? You're choosing to do something now because you get benefit in the future.

27:26But it's also true that it's not like if you exercise now, you're going to live to be 100 later. You have to keep doing it. So we call this the active grandparent hypothesis. So humans are unusual in that we evolved to live after we stop reproducing so most animals right this as soon as they stop having babies natural selection doesn't care about them at all right they're just gone right but humans are different we a typical hunter-gatherer will live about two decades at least after after they stop reproducing and um but they're not just like retiring and going to you know florida or whatever you know you know we're south of spain or whatever it is you're doing when you retire or sitting back and just watching the television, they're still active, right?

28:17They're still hunting, they're still gathering. And then that physical activity turns on all those repair and maintenance mechanisms, which keeps people healthy. So the trick is not to just think, well, I exercise when I'm young and that'll keep me healthy when I'm older, is to continue to stay physically active as you age. And there's plenty of epidemiological data that supports this. There are studies which show that as people age, the benefits of exercise actually become bigger, not smaller in terms of their long-term health. Because my dad says to me, I've never seen my dad go to the gym, and he now says to me, he's 76.

28:53He either says, it's too late for me to be doing this, or exercise is for young people. Not true. Absolutely not true. Quite the reverse. So what would it do to his body then if he started to exercise? Well, I mean, I'm not a gerontologist, so I'm not an expert on, and furthermore, everybody's a bit different in terms of what their health issues are and their fitness levels are. But the benefits are the same for everybody. When you're physically active, you start pumping blood around your body, you turn on all these proteins. But why is it more for him then? Why would it be more beneficial for him?

29:24Well, because as we age, senescence starts to catch up with us. Aging is as the years tick by, right? Senescence is the deterioration that is correlated with age. And what exercise does is it slows senescence. So like one of the big problems that people run into as they age in our society is the muscle wasting. The technical term is sarcopenia. Sarco means flesh in Greek, and penia means loss. So flesh loss, it kind of sounds awful, right? But sarcopenia is what happens when people get old and they get frail and they can't do stuff, right? So it gets hard to get off the toilet or get out of a chair.

30:01it gets hard to lift your bags and you know everything becomes a little bit more difficult and when that happens a vicious cycle sets in because then you do less of those things and you become even more frail and then and we all seen this you know people elderly individuals who really struggle to do basic things and their bodies deteriorated in a rapid rage you can you can it's not causal it's correlative but you know the the speed at which people walk is very predictive of how long they're going to live as they age, right? And it's not because walking fast is necessarily all that great for you.

30:34It's just a good signpost. It's an indicator of how much your body is deteriorating. So as people age, staying physically active slows the rate at which all the systems in their body senesce and helps them stay active and healthy and helps them stay mentally alert. It slows dementia. It slows, you know, heart disease. It slows metabolic disease. I mean, I don't even know where to stop the list.

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33:14Can we talk about the mental impacts as well as the physical ones? Sure. I'm a big advocate for mental health, particularly in young men. But I now see among my parents as they get older and their friends, the prevalence of people having mental health challenges much later in life, having never had a real issue with it when life was busy, when they had children and they had purpose and they had a job and all these things. So I'd love to talk about the impact of exercise. Yeah, it's actually, I think, one of the most compelling reasons to help people, to help motivate people because, you know, especially when you're young, but also as you age, you know, when you're 20, you think, okay, it doesn't matter.

33:55But exercise when you're 20 can have huge effects, for example, on depression. So when you're physically active, you produce all kinds of neurotransmitters, right? I produce dopamine, which is the molecule that basically says, do it again, right? I produce serotonin, which is important for regulating mood and anxiety and frustration and anger. I produce, I guess we call it epinephrine. I think you call it adrenaline here in England, right? Which, you know, again, makes you kind of more active. I produce brain-derived neurotropic growth factor, which produces more neurons in my brain. It keeps my brain growing.

34:34I produce opioids, right? Which, you know, would be a leak. Oh, absolutely. You're producing all kinds of endogenous opioids, which it's one of the reasons why, you know, you can run, like if you ever, I don't know if you ever run a marathon or anything like that, but I've sometimes, you know, run long races like marathons and I feel, you know, at the end of the race, I'll suddenly, my feet, like, I realized I have a blister the size of, you know, New York City. But you've never felt it when you... I didn't feel it because the opioids were just making my brain happy, right? You produce endocannabinoids, which is the same stuff when you, when you smoke cannabis, right?

35:08And it gives you runner's high, right? In fact, the first time I ran the London Marathon once, and I remember, you know, I was just running for fun. I wasn't, you know, racing. And I had just a grand time. I had a wonderful time. I remember as I ran by Big Ben right towards the finish, I remember thinking, wow, Big Ben is so big. And I realized I'm high, right? Because Big Ben actually isn't that big, is it? But Big Ben looks really... Because when you're high, everything is exaggerated. White is whiter and blue is bluer and the birds are tweedier and Big Ben is bigger and whatever. But the point is that your brain produces this cocktail of molecules that make you feel good.

35:55They also, we have data. There are, I don't know how many, there are at least, we just did a big study in our lab, a meta-analysis, But there are dozens, maybe many dozens of studies, prospective gold standard studies, where they take a group of individuals who are all clinically diagnosed with major depressive disorder. So these are people who are struggling. And half of them are assigned to exercise, and then half of them are assigned to some kind of pharmaceutical. right and in almost all of the studies the exercise has more of an effect than taking a pharmaceutical and we actually understand them so we have data that tells us the prevalence of you know the effectiveness we also have data which tells us the the mechanisms we understand some of the the molecular mechanisms you know the the the self-medication that occurs right so we so we we know that this is very potent effects um and and yet there's how often when somebody goes in to see um a counselor or a psychiatrist i mean often nobody even asks whether they they're being physically active they don't ask whether they're exercising and and it's just it's just a failure of our of our medical system um our medical systems to recognize just how important physical activity is for so many aspects of our body but again let's be let's be careful right let's not sell this as a as a I think I'm overdoing this in a way it's not a magic bullet right it doesn't mean that any everybody who gets depression will instantly have their depression gone it increases your your your you know exercise decreases your vulnerability it can help but it's not like a magic bullet yeah but it helps just there are there are no magic bullets people who exercise also still die you know but it is it is one of the most potent ways to reduce your vulnerability to a wide range of diseases.

37:52And in many cases, it can also help treat a number of diseases. I think one of the other challenges is just how busy we all are. I was thinking about this conversation because I went to a party on Saturday night, and the conversation I kept having repeated itself. How are you? Oh, I've got so much going on at the moment. What are you doing at the moment? Oh, I've hardly got time to go to the bathroom at the moment. I'm so busy. there is this real disconnect isn't there between feeling that we have to be pushing ourselves all of the time and finding the opportunity to do the things that we that we know are good for us yeah i mean you know it is an issue i mean it's it's also a question of priority yeah and how we evaluate our priorities and and and again you know i'm often too busy to um and i would i want to make those excuses but then i find ways to force myself because a it's my it's my job and i don't want to be a hypocrite yeah and but b um you know i've decided as i get older that that there are two things i just don't like to uh compromise on and one is sleep and the other is exercise i just you know it's uh they're important to me and i'm just not a and it and also when i'm not exercising I'm not doing the right thing by my family as well.

39:08But I think everybody who does that probably could think about how they could adjust

39:18other things they do in their lives. But if you're commuting and you have kids and whatever, yeah, it is tough. There's no question about it. Because again, we live in a world where not only is physical activity unnecessary, sometimes you have to go out of your way to do it. That's one of the challenges. It's hard to know what to say to people who already feel like they're operating at 100%. And I wonder whether for them it's reducing stress. I mean, stress obviously is a huge factor, right, when it comes to longevity and health. Yeah. And of course, physical activity does reduce stress. There's no question about it.

39:51I mean, everybody knows that. Going for a walk. Everybody knows going for a walk outside, even on a gray, rainy day, is better than not going for a walk, right? So, yeah, I don't have a simple answer to that one, obviously. But I think as a society, we need to find ways, and as friends and neighbors and whatever, to help each other. Again, we evolved to be physically active for two reasons and two reasons only, right? When it's necessary or when it's rewarding. So we have to help even make it necessary and rewarding. And there are many ways to do that, but there's no one-size-fits-all solution.

40:28Can we talk then about the power of being sedentary? You've just said that sleep is really important for you. Can you tell us, first of all, what you've done to make sure that you prioritize sleep and get the right sleep that works for you? Well, actually, interesting. You know, we're all told that we have eight hours of sleep a night. Yeah. That's just not true, actually. But if you look at epidemiological data, again, large samples, right, where you graph how much sleep you get a night and how long you live, it's a U-shaped curve. So people who don't get much sleep, they do run into trouble.

41:00There's no question about that. People who sleep too much also run into trouble. That's usually because there's something wrong that's making them sleep too much. But the bottom of the curve for almost everybody, for most populations, and then there's variation. Everybody's different. So you might be different from me. It's about seven hours. So it turns out that seven hours is, if you want to say an optimum, you know, based the bottom of that curve, seven hours turns out to be the optimum. furthermore if you look in pop and we think oh well you know modern world you know we have iphones and television and electric lights and all that and that's ruined sleep right edison you know ruined sleep right um populations worth which have none of these things right there's no electricity no iphones or whatever they sleep less than seven hours on average like the hunter gathers like sleep six and a half hours they don't nap either um for the most part um and you know Some of them are early risers and some of them are night owls and whatever.

41:54And there's always somebody awake making noise in camp, et cetera. But it turns out that the idea that we evolved to sleep eight hours is a bit of an exaggeration. And what happens, though, is that what I call the sleep industrial complex. But there are people out there to make money off this, right? Oh, you're not getting enough sleep, so buy this product. by this strip you can put on your nose. Pills, of course, which are terrible for you. I mean, hypnotic. The pills that sleep, sleeping pills are really bad for you. And then we, or this mattress or you have to get a special curtains to block out every photon of light or whatever.

42:37We're making people stressed about sleep, but guess what stress does? Stress prevents you from sleeping. So the more we make people stressed about their sleep, the less well they're going to sleep. And it just drives a vicious circle. And then the more they're going to go and run and buy your product. So we just, you know, yes, too little sleep is a problem. People who don't get enough sleep need to find ways to help them. But making people anxious about sleep is, I think, exactly the wrong way to help them sleep. I find if I wake up in the night, the one thing that stops me getting back to sleep is the fear of not getting back to sleep.

43:10That's right. That's right. Yeah. And they're like, oh my God, something's wrong. I woke up in the middle of the night. But you know, everybody wakes up in the middle of the night sometimes. It's completely normal. But if you're less worried about it, your cortisol levels won't rise and prevent you from sleeping. Because cortisol is an arousal hormone, right? When you're stressed. So cortisol doesn't cause you to be stressed. Cortisol comes up when you are stressed. When I'm teaching, I actually showed this wonderful experiment where they had a bunch of people jump out of airplanes. And they measured, you can measure cortisol in saliva.

43:42So they had little tubes as they were getting in the airplane and about to jump out. And of course, the first time they jumped out, their cortisol levels were literally sky high, right? They're like, oh my God, I'm going to jump out in an airplane. They're really high cortisol levels. And then what they did is then like every week they repeated the jump, right? And by seven weeks, there was like, eh, there was like no cortisol, right? They're still jumping from the same height, but they were no longer stressed because they're like now, oh yeah, I'm going to jump out of a plane again. But cortisol turns on your fight and flight mechanisms, right?

44:13It helps you run away from the lion or whatever. And all of that prevents you from sleeping. So the trick to helping people sleep is to help them avoid stress. And on a similar note, talking about sleep and getting the right rest and recovery, I have a few friends, when I talk to them about exercise, they say, well, I'm just too tired. And I often say to them, if you start exercising, I bet you'll be less tired. This is true. Is it true? Yes. Because exercise, you know, like, well, there's different kinds of fatigue, right? So one kind of fatigue is the fatigue from, I mean, you know, I did a really long run this weekend, right?

44:54And I was tired afterwards. That's because I ran a ridiculous number of miles, right? But there's the other fatigue, which is sort of more kind of a malaise, just feeling lack of energy and all that kind of stuff. But exercise, of course, liberates all that energy. It turns on your endorphins and it turns on growth hormone, GH, which gives you this energy surge. Again, this is part of the issue, right? Which is that we didn't evolve to say, oh, I feel awful. I think I'm going to go for a run. Nobody in the Paleolithic ever did that, right? they didn't think oh god i feel awful i'm gonna go i'm gonna go for a pointless five mile run you know nobody did that right the reason they went out and were physically active was they're they're hungry right or their children were hungry or their their friends were hungry and they had to go get food and they had to you know do something right so they they never you know it was never a prescription for for feeling bad it was just a necessity right so are you optimistic or pessimistic about our future when it comes to exercise and fitness and health and wellness because social media has exploded in the last few years so we can spend hours not leaving the sofa we can click one button now and have our lovely food that's highly calorific delivered to our front door and it was only when we were younger that you'd have to actually at least walk to the takeaway right to get yourself a kebab now you don't even have to walk anywhere i kind of feel like you know we've got businesses spending billions of pounds to try and convince us to eat their refined food.

46:23It feels like society is stacked so heavily against us. So many billions of pounds are being spent for these businesses to be successful. It's bloody hard for us as individuals to kind of almost find our way through and remind ourselves what we really should be doing. This is true. So I do most of my fieldwork in Africa where we're talking about the industrialized Western world, which is actually a small percentage of the world's population. Right now, this transition is occurring rapidly everywhere around the world, right? In the area in Kenya, where I've been working for many years, right? Diabetes is the fastest growing disease, right?

47:00Obesity is rising. People are moving to the cities. They've got mopeds and bicycles and cars. And, you know, there's more, of course, as you say, you know, ultra processed foods. And, you know, if we can't afford it, how do you think countries and poor countries in the global South are going to afford this. They can't, right? It's a growing crisis. So I'm deeply concerned about this, because it's not just in America and UK and Europe, et cetera. This is happening really fast all over the planet. And we need to act. And the way to do that is through some combination of public health messaging, but also I think we're going to have to maybe start thinking about regulation.

47:49I mean, you know, we don't like to regulate things and force people to do things. But it is true that there are a lot of companies out there that are making a lot of money by making us sick because they're giving us what we want. And on the one hand, we say, well, you know, they're not forcing us to buy these products. But people don't understand the products. And so I think we need as a society to ask ourselves, you know, how we want to help regulate the world right to help people help themselves should we tax them should we force them to you know put labels on their foods just the way we have them for tobacco we also need to push more for physical education for kids for for exercise in schools because the habits people develop when they're young are important as they get older we need to do more public education so it used to be that that people who are wealthy were overweight and unfit and people who were who were you know the working poor, they're the ones who are very physically active and they were thinned.

48:47Now it's the reverse, right? Now people who have means can afford to go to gyms and they can afford to buy really healthy food. And people who are struggling have to commute long distances and they have multiple jobs and they don't have time to exercise. If you go to a marathon, you're going to see a lot of rich people. Or if you go to an Ironman, I've been to Ironman a few times in Kona. I didn't run them, by the way. I was there in the medical tent. I mean, they're millionaires mostly. I mean, these are really, really, really rich people who've made a gazillion dollars or pounds or whatever.

49:21And then probably saw their doctor who said, you're about to die because all you've been doing is making money sitting in the chair. And so they took the same intensity that they used for becoming super wealthy to becoming super fit. And so to get to Kona, you have to spend thousands of dollars to get there. you buy a 30, you know, 20 ,000 pound bike. And, you know, I mean, these are wealthy people. There's nothing wrong with it, right? I'm not opposed to it. But these are mostly very wealthy people who have the time to train for a full Ironman. It's a ridiculous amount of time. Most people can't do that, right?

49:56There's big challenges ahead. Before we move on to our quickfire questions, just a few things I just want to cover off with you. Just a reminder to people who've heard this fascinating conversation, how much of illness is preventable by us just making a small change? So according to the Center for Disease Control in the United States, which has taken a few hits recently dealing with COVID, but nonetheless, according to the CDC, 75 % of the time when somebody walks into a doctor's office, it's for a disease that's technically classified as preventable. 75 % of the time. And furthermore, we also know from many studies that our medical care pretty much affects about 10 % of people's healthcare outcomes.

50:43It's actually pretty good. So we're spending, in the United States, we're spending 20 % of our GDP on diseases, 75 % of which are preventable, to affect 10 % of people's healthcare outcomes. It's completely stupid, right? It makes absolutely no sense. if we got people to exercise more and also eat healthier and um we could eliminate a lot i mean people are still going to die of course we're all going to die of something but we could we could reduce people's disability and chronic diseases and increase their quality of life enormously and to that end from people who've been impacted by this conversation what what what's the first thing, the most valuable thing that they can do after listening to this that will make a difference.

51:28Just recognize that you don't have to run a marathon or a Swingling channel or whatever. Just anything is better than nothing. And just build up slowly and gradually, but also make it fun. You know, if you don't like to exercise, arrange to go for a walk with a friend. That's not exercise. It's just nice. Go dancing with somebody you find worth dancing with. Do something that's fun, right? And then, you know, before you know it, you'll enjoy it more. And then it becomes more positive. And becoming a negative thing, it becomes more of a positive thing. And then you can increase it. And, you know, just a few minutes a day is better than no minutes a day.

52:09It doesn't have to be all or nothing. We've spoken a lot about exercise. What have you learned about diet? Oh my gosh, that would take a very, very long conversation. You can give us a few minutes on it, not everything. But if you were to sit down with your wife and she would say, come on, Daniel, what have you learned that we can bring into the family today? What would you say? Well, I would say that, you know, again, there are a lot of people out there, many of them quacks, some of them intentionally quacks, some of them self-deceived quacks, who are trying to tell us what the optimal diet is.

52:37And just like there's no optimal exercise, let me tell you, there is no optimal diet, despite what people claim. Humans evolved to eat anything. you can you can eat you can be an inuit and live on meat and you can be a vegan and live you know not even eating any dairy not neither necessarily up you know that can make make you super healthy but you can our bodies evolved to eat pretty much anything and we also never evolved to diet we never evolved to lose weight and so um so you know again just like with exercise there's a lot of useful information we can get from taking an evolutionary perspective to diet but It's a long and complicated story.

53:15We'll have another conversation one time about diet. But I think it's a good message for people who are struggling with diet and struggling to lose weight. Their body's not designed to do that. Absolutely. Your body has to counter vast numbers of adaptations that it has to hold on to weight. So if you think it's hard to diet, it's because it really is hard to diet. And I love your kind of clear but all-encompassing message that there is no perfection, there is no golden bullet, there is no one thing you need to do. Are you frustrated that we live in a world where that feels to be really prevalent now?

53:48Oh, yeah. I mean, that's how you make money, right? I mean, I could make way more money if I had a book with seven steps to be super healthy. You know, I could just make them up, right? People do that all the time, right? And because we want simple answers to complex problems. And the problem is that many problems are complex and they defy simple answers. But that's not what people want to hear. And why is it important to you then not to go down that clickbait route? Because I believe in telling the truth. Brilliant. Right. Are you ready for some quickfire questions? Sure. So the first one is, what are the three most important non-negotiable behaviors to you?

54:29Things that you or people around you must bring to the table? I really dislike it when people are dishonest. Uh-huh. I really dislike it when people are mean.

54:45and also close-minded right very good what's your biggest strength? what's your greatest weakness?

54:57I have no idea what my biggest strength is I think it's because I I don't know I'm very fortunate I get to do what I love to do and And I think maybe my biggest strength is also my biggest weakness is that I get really obsessed by what I'm interested in. So that can be a good thing and it can also be a bad thing. And what are you obsessed about at the moment? Oh, right now? Actually, I'm working a book. I'm trying to do a kind of a sequel to exercise. I'm writing a book about diet. And I've become partly to help educate myself, but also because I teach anatomy and physiology and nutrition and digestion.

55:34and I become really obsessed with the research I'm doing on this book, yeah, and driving my wife crazy. What would you say to a teenage Daniel just starting out on this journey?

55:49Oh, wow. You know, it's funny. I mean, life has taken all kinds of interesting courses, but it's funny. I was just asked this question the other night. I was having dinner with a colleague in Oxford, and he brought along some students. And I said, prepare for your midlife crisis, right? Because as you get older, you're going to ask yourself, why am I doing what I'm doing? Is it really worth all the effort and energy I've poured into it? Because it's going to happen at some point in your life. And if you start thinking now about doing something that really will provide lifelong value and make the world a better place, now's the time to think about it so that you don't run into this problem later on.

56:29That is brilliant. If you go back to one moment in your life, Where would you go and why?

56:38I wouldn't. I don't believe in regret. It's a very unhelpful emotion. I mean, I've had a very lucky life so far. I mean, there have been tough times, just like with everybody else. But, I mean, I've had a fantastic journey so far. I mean, I've got a wonderful wife and a great kid and got a great job and been able to travel to all kinds of wonderful places. and being a scientist and professor at a great university has been an incredible privilege. You know, there have been struggles and difficulties, but I don't believe in regret. It's not a very healthy way of thinking about things. Final question, and thank you very much for the time you've given us.

57:16What would you leave us thinking about as your one golden rule for living a high-performance life? Remember that the world that we live in today, with all its wonderful things, and also challenging things is not the world in which we evolved, right? And we have to, and that the Western industrialized world that many of us live in is not the world that most people live in. And the world that you think of, your life that you may think is normal, right? You may think it's normal to get in a metal tube and fly through the air. and you may think it's normal to eat breakfast cereal from a box and you may think it's normal to wear shoes and all that.

58:03None of that's normal from an evolutionary perspective. It doesn't mean it's bad or good, but it means that we are often mismatched to the world that we live in and we have to be conscious and careful and thoughtful about the choices that we make and the world that we live in because it has all kinds of effects. Brilliant. Thank you so much. I think it's a really good reminder for all of us that, of course, it is normal to us because it's our lived experience, right? But actually, for you to come on here and share with us that, you know, we're not in this moment. We weren't created the moment we were born, right?

58:37There is so many years of evolutionary history behind us that impacts how challenging life can be. Yeah, there's an old expression. It's actually a title of an essay. but nothing in biology makes sense except in the light of evolution right because we weren't engineered we weren't designed we evolved and that's if you understand why we are the way we are you have to understand that evolutionary history in fact you could say that nothing makes sense except in the light of evolution doesn't have to even biology right yeah and so that evolutionary history that story of how we got to be the way we are helps explain why we are the way we are and that why helps us answer a lot of important questions well it's been really helpful so thank you so much my pleasure

59:24And that brings us to the end of this episode. I mean, what an education. I don't know about you, but I have listened back to that episode a couple of times, made numerous notes, and it is going to inform the way that I live, how I think the small decisions that I make. Thank you so much as always for trusting High Performance for these conversations. Hit follow if you can. It changes the game for us. Don't forget, you can also watch on YouTube as well as listen where you get your podcasts. But most importantly of all, remain humble, curious, and empathetic, and I'll see you soon.

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