Feel Better, Live More with Dr Rangan Chatterjee - #128 The Surprising Truth About Exercise with Professor Daniel Lieberman

Episode Date: October 20, 2020

Today’s episode will change the way you feel about exercise – and yourself. Do you ever feel guilty for taking the lift instead of the stairs? For swapping that workout for a lie in, or for having zero desire to run a marathon? If so, my guest has some reassuring words on why an aversion to exercise is completely natural. And some valuable advice on how we can overcome that to reap the multiple health benefits.  Dr Daniel Lieberman is a paleoanthropologist and Professor of Human Evolutionary Biology at Harvard University. He has studied evolution and researched cultures all over the globe, to explain the science of how and why we move today. Whether you struggle to exercise or you’re a committed fitness fan, I think you’ll find his new perspectives on physical activity absolutely fascinating.  Among the many topics we cover in this conversation, Daniel addresses the following questions: Can exercise really help you lose weight? Does running ruin your knees? Should we be running barefoot? Is sitting the new smoking? Do you need eight hours’ sleep a night?  Should activity levels decline with age? I think some of his answers might really surprise you. I hope this conversation helps you feel better about the role of exercise in your life and have more compassion for yourself. I think it might just inspire you to move more, too. Show notes available at drchatterjee.com/128 Follow me on instagram.com/drchatterjee/ Follow me on facebook.com/DrChatterjee/ Follow me on twitter.com/drchatterjeeuk DISCLAIMER: The content in the podcast and on this webpage is not intended to constitute or be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or other qualified health care provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website.

And I think we need to understand that we don't just get to decide what we do with our bodies. Our bodies are evolved over millions and millions of generations and we need to be compassionate and understand that and work with our biology to find better solutions. I mean, our instincts are constantly pulling us not to exercise. Our instincts are deep and they're powerful. It is a completely normal natural instinct to want to avoid exertion and don't ever feel bad about it. Hi, my name is Rangan Chatterjee. Welcome to Feel Better Live More. Today's conversation I think may be helpful in reframing the way that you think about exercise. Do you ever feel

guilty for taking the lift instead of the stairs? Or for swapping that early morning workout for a lie-in? Or for having zero desire to run a marathon? You see, if exercise is so healthy, why do many of us dislike or avoid it? If we're born to walk and run, why do most of us take it easy whenever we can? Well, my guest today is Dr. Daniel Lieberman, Professor of Human Evolutionary Biology at Harvard University and a pioneering researcher on the evolution of human physical activity. He's written a brilliant new book called Exercised, The Science of Physical Activity, Rest and Health, where he tells a story of how we never

evolved to exercise, which really means us doing voluntary physical activity for the sake of our health. My conversation with Daniel covers a whole variety of different topics, including why an aversion to exercise is completely natural and the exact role that exercise plays in weight loss. We also discuss if running is bad for your knees, whether we should or shouldn't be running barefoot, if sitting is the new smoking, whether we really need eight hours sleep a night, and if it is normal and desirable for our activity levels to decline as we age. Daniel is an incredible researcher and a world-renowned expert in his field, and I think some of his ideas and answers might really surprise you. My hope is that this conversation helps you feel better about the role

that exercise plays in your life and helps you to have more compassion for yourself. I think it might just inspire you to move a little bit more as well. So whether you struggle to exercise or you are a committed fitness fan, I think you'll find his new perspectives on physical activity absolutely fascinating. And now, here is my conversation with the wonderful Dr. Daniel Lieberman. Things changed when I wrote the Born to Run paper in Nature, the paper that in 2004 with Dennis Bramble, where we argued that humans evolved to be long distance runners.

And we spent many years writing that paper. And the process of writing that paper got me more excited about my running. And it became like a feedback loop. And before I knew it, I was doing longer distances. And I just got totally hooked. Now we study running in my, you know, all kinds of aspects of writing in my lab. So it's kind of like it's become a part of my life. Yeah.

Well, thanks for sharing that. And that was a, and still is, a seminal paper. I believe you got the title from Bruce Springsteen. Is that right? We did indeed. We did indeed. And there's actually in my office thatuce springsteen poster is over the door oh fantastic well hey that that resonates with me i've got a i've got a big cd collection of

bruce springsteen albums in the house i think when i was doing i finished off my elective at the mayo clinic in uh something like 2000 i was in scottsdale in arizona for a few weeks doing an elective and on the way back i was was stopped off in New York and I managed to get tickets to see Bruce in Madison Square Garden. And as a, you know, as a early twenties at the time, I think I died and gone to heaven. I was like, is this really happening? Um, so yeah, we, we share a love for Bruce Springsteen, but you know, to get to the topic of hand, you've written a fabulous book on exercise, on movement, on physical activity. And actually, I thought right at the start, we should probably define these terms because they're terms that people use interchangeably, but they can mean quite different things, can't they?

Yeah, no, it's a good point. So physical activity is just moving, right? You know, getting up and, you know, if I were to get up and go to the bathroom, that would be physical activity of a sort, right? But exercise is sort of planned, voluntary physical activity for the sake of health and fitness. And so it's a kind of movement, but it's a very modern kind of movement. And I should also say, we should probably also define the word exercised, right? Which is why I titled the book that way, because exercise is to be anxious and nervous and harassed and, you know, concerned about something. And, you know, these words, of course, have ancient origins. But, you know, when we do, you know, when we do math

exercises in school or, you know, soldiers do exercises, right? It's not always a good thing, right? And I think that sort of encapsulates the kind of ambiguity and dual role that exercise has in our life. We know it's good for us, but a lot of us are really confused and anxious and harassed and concerned about it. And really, I wanted to write a book that addressed that kind of duality between physical activity and exercise and why it's such a confusing and complicated topic. Yeah. One thing I find really interesting as I familiarize myself with your more recent work is this idea that, you know, everybody listening and watching to this right now, Daniel, I'm sure is aware that physical activity is going to be beneficial in some way for them. And as a society, we're trying to move more. I'm a medical doctor. We're always being told

that we should be encouraging our patients to move more and actually to exercise, which potentially is problematic. But it's interesting, isn't it, that we're moving less as humans, but we're living longer. Yeah. So what's going on there? Well, I mean, I think it's part of the confusion people have, right? We're told that, you know, exercise is medicine, and that if you don't exercise, you'll get sick. And then they look at people like, well, I'll be very political. They look at people like Donald Trump, who doesn't exercise and actually believes that exercise is like wastes your energy, right? And they see he's, you know, President of the United States in his 70s, and they wonder

what's going on. And the answer is that, you know, I think we oversimplify something that is very important, which is that exercise really does improve your health. Exercise really decreases your chances of getting sick. But on top of that, we have an incredible medical system. As you well know, you're a practicing physician. And we're able to patch people up and keep them going and treat their diseases and give them pills to lower their blood pressure and other pills to lower their cholesterol and all the other sequelae, the things that result from being physically inactive, and we can keep going. But it comes at a cost, and it comes at an increased risk and an increased vulnerability of a wide range of diseases.

The data are unquestionable. 150 minutes a week of physical activity, just a brisk walk, can lower your relative risk of dying at a given age by 50%. That's not a number I just pulled out of a hat. That's a really, really, really solid number based on many, many, many studies. But it's not a magic bullet. It's not a guarantee of good health. You can still get cancer. You can still get injured you know, guarantee of good health, you can still get cancer, you can still get injured, and vice versa. So we need to, you know, be kind of clear about what the benefits are, but also the fact that it's, this is a statistical issue, and it's a complicated issue,

and there are no simple solutions to anything. So why is it when the data and the science is really clear that, as you say, 150 minutes of physical activity each week will have multiple benefits or, or let me rephrase that, may have multiple benefits on your wellbeing and your longevity. Why does so many of us struggle to do that? Because it's, it's, it's abnormal. I mean, it's, our instincts are constantly pulling us not to exercise. I mean, our instincts are deep and they're powerful. I mean, it's our instincts are constantly pulling us not to exercise. I mean, our instincts are deep and they're powerful. I mean, for, for millions of years, our ancestors struggled to get enough energy to eat, right? They, every day they had to work, they didn't

go crazy hard. You know, they didn't like work eight hours a day on their feet, you know, you know, struggling to get enough food. They, they, you know, average hunter gatherers seem to work, you know, moderately hard for about two and a half hours a day, two and a quarter hours a day, and then light tasks for the rest of the day. And they sit as much as we do, around nine to ten hours a day. But that would give them just enough food to survive. There are no obese hunter-gatherers, right? And if they were to go for it, like what I did this morning, go for a long run just for the hell of it in the morning, they would then waste all that energy which they could use towards reproduction and the things that natural selection cares about. So nobody in the Stone Age ever went for a morning run for the fun of it. It's a bad idea.

And whenever you have a chance to save energy, you should until recently. You should until recently. And now we live in this really strange, interesting, modern world, wonderful in all kinds of regards, where we can spend our entire day without ever getting our heart rate up, press buttons to get food and shopping carts. And I don't even have to move my hand when I brush my teeth if I didn't want to. I get an electric toothbrush. I mean, Everything is mechanical. The result is that we no longer have to be physically active. We now have to do something really weird, which is to choose to be physically active. Although we know up here in our brains that it's good for us,

all kinds of instincts just kick in to tell us not to. I think the best evidence for that are when you have like stairway next to an escalator, right? You must see them, you know, there are tube stops all over the place and then, you know, airports everywhere. We all know this phenomenon, right? And it doesn't matter where you are in the world. People have studied this in Japan and in Denmark and in America and in Israel and, you know, various places, wherever there is a stairway next to an escalator, less than 5% of people take the stairway. And if you put a sign up, that just goes up just a wee bit, right? If you put escalators in the Kalahari Desert, you know, they would take the escalator there too. It's an instant.

Yeah. And I think what you just said there about the Kalahari Desert really, I think it brings it to life for people because a lot of people feel bad. They feel guilt. They feel shame that they're not moving as much as either their doctor has told them, the news has asked them to do, or even people they're following on social media who post a photo, hey, just did my 10k run before breakfast, how are you all doing today? You know, that kind of meme, which I think if you find it inspiring, and you're like, oh, man, I didn't do anything, I want to do that. Great. But for many people,

they watch that and day in, day out, they're feeding their brains with that thinking, I'm some kind of failure. Like, look at all these people who can move their body every day and are vibrant and full of energy. Yet just getting through the day is a real struggle. And I think that's one of the beautiful things in your book is that you help people not to feel bad about it. You're sort of arguing that we've not evolved to exercise. Absolutely. We didn't. Look, we also didn't evolve to go to school, right? I mean, we didn't, you know, until recently, almost nobody read and nobody, of course,

schools didn't exist, right? I mean, there are so many things of our modern world that are good for us. I mean, no parent thinks that sending their kid to school is bad and they shouldn't learn, that their kids shouldn't learn to read. But, you know, that's also a modern abnormal thing. And think about how we get school to work, right? We make it compulsory, but we also try to make it fun too, right? You know, we have recess and all kinds of, you know, you meet your friends there and we try to make school both fun and necessary. And I think we should treat exercise the way we treat education because it's a modern, abnormal thing, but it's good for us. And we should make it necessary, but we should also try to make it fun.

But the last thing we should do is make people feel bad about it because making people feel bad about doing what's natural for them doesn't help anybody. I think the same thing goes with dieting, right? I mean, we never evolved to lose weight, but we all, a lot of people are trying to lose weight and for good reason, but when they fail on their diet, it's not because of some moral failing, it's because there are hundreds of adaptations in their bodies, which want to hold onto that fat and, you know, and elicit a kind of a fast, you know, energetic crisis in their bodies to hold on to that energy.

And it's not their fault that they're having a hard time with weight. It's the fault of their biology. And yet we then blame them and make them feel bad. And I think we need to understand that our bodies aren't, we don't just get to decide what we do with our bodies. Our bodies are evolved and over millions and millions of generations. And we have, and we need to be compassionate and understand that and work with our biology to find better solutions. I mean, what we've done with exercise is we've medicalized it and I have nothing wrong with the medical profession. Obviously I almost

became a physician myself, but doctors, most doctors job is to treat people when they're sick, not to prevent them from getting sick. And that's part of the medical system as a whole. That's another issue. But, but the other thing we've done with, with, with, with exercise is we've commercialized it. We've industrialized it. We've commodified it. You know, we tell people to just do it, right? And, and again, there's nothing wrong with medicalizing exercise. There's nothing wrong with commercializing and industrializing exercise, but clearly it's not enough because like in the United States, I don't know what the data are in England. I've been trying to find good data in England. There's not as much, but in the United States, only 20% of Americans actually exercise in their leisure time. That's a really staggering

number, right? There are people who are physically active, you know, but not many people actually get out and do it. And there's a reason for that. It's not because they're lazy or bad or should feel guilty or ashamed. They're just being normal human beings. Yeah. You know, it really is wonderful to have someone with your pedigree. You're such an esteemed, highly respected researcher, professor. You're basically saying we need to be kind to ourselves. We need to be compassionate to ourselves. You're making the case with physical activity and exercise that we need to be compassionate to ourselves. But I love what you said there about trying to lose weight. We've not

evolved to lose weight. And what you just said, what you just mentioned there is a sort of central case I've been writing about over the last few months for my next book, which is on weight loss. And I very much agree, we have to be kind and compassionate to ourselves and understand we're kind of fighting our biology. so removed from the environment in which we've evolved that therefore, you know, we're not doing anything necessarily wrong. We're just doing what humans have always said. Humans have always tried to make things easy, right? We've always looked for high calorie, energy dense foods, you know, for as little energy as possible. It just so happens now that on my smartphone, I can go on a shopping app and have that delivered to my house without actually moving anywhere. So I think it really does help people feel better. I read an article with you, Daniel, recently that I think you wrote in the British press. And you said in it that you were the kid who never got picked for the sports team

at school. Yet, here we are, we're having a conversation and it's early your time. What is it? 7.30? Quarter to eight? Something like that? It's not that early here. 8.30. But you've already been for a run. And that made me think about what you've just said about we've got to make it fun for people. We've got to, you know, we made school compulsory, but we also try and make it fun. And you're sort of making a similar case for exercise. So is part of the problem also, like with you, and you've obviously overcome that and you are still someone who moves regularly, but many people have that experience at school. They're not picked for the teams. They're made

to feel shame and bad about themselves, that they can't be sporty like their friends who have been picked in the team. And that puts them off moving their bodies for life. Oh, absolutely. I mean, I was lucky because although I was terrible, I really was picked less for sports. I, for example, played on a soccer team. You call it football. And in my town that I grew up in, it was a really good soccer town. And so there were kids on my team who were so much better than me. I just sat on

the bench. I almost never got to play because I wasn't very good. And I felt very insecure about my body. But I was lucky that I had parents who loved to hike and loved to, we went skiing in the winter, cross-country skiing. And my mother jogged and my father jogged too. So they were physically active, but they didn't play sports. I don't think they ever watched any sports event ever. I don't think. I played tennis a bit, but that was – I had to walk to a tennis court.

That was fine, but they weren't interested in any of that. I don't think they ever came to any game I was ever in, partly because I sat on the bench. I grew up thinking it was normal to be physically active, but not interested in sports. So much of physical activity that kids encounter is sports. There's a whole chapter in my book on sports. Sports can have exercise, but it doesn't always have exercise. And that exercise isn't always necessarily healthy. Look at American football. I mean, that's a really profoundly unhealthy sport. And we have more and more data to show that not just in terms of concussions, but also in terms of heart disease and other kinds of problems that arise from, you know,

bulking up, making these sort of sumo wrestler-sized sort of linemen in the sport. But we could do a better job of making it fun. I mean, some schools do that. But making sure it's about fitness. My university, Harvard, has a huge athletics program. We have 40 teams. One of the largest athletic programs in the United States, even though this is not a powerhouse school in terms of athletics. But the athletics department really mostly serves the athletes on campus. And their job isn't really that much to

get the other 80% of students to be physically to be physically active and, and, and surprise, surprise, the vast majority of Harvard students, about 75% don't meet the minimum level of physical activity that you need in the United States. And, and that's partly because we don't make it fun for them. You know, there's no opportunities for them and probably most of them, and all of them would like to do more exercise, but they, they're busy and they're stressed and they've got courses and classes and they don't have to do it.

And, you know, we could do a much better job of helping them be active. And they want us to do a better job of helping them be active. It's not something you can just snap your fingers and do on your own. It's an interesting dilemma, isn't it? That we look up to these incredible athletes with superhuman performances, you know, the American footballers, let's say in the States or, you know, Elliot Kipchoge, the runner who can, you know, run a marathon, frankly, in a time that just makes me shudder even thinking about the fact that he can do that in under two hours. But there's a difference, isn't there? It's the case you're sort of making that that's kind of elite performance. It doesn't mean that's healthy. It doesn't mean that's what we

should all be striving for. And I think why I find that interesting is because, have you heard of Parkrun? Yes, of course. Yeah, no, it's wonderful. Parkrun. Fantastic. Yeah. But I mean, I'd love to talk about Parkrun at some point because there are so many aspects there, community, you know, the social aspects to moving together, whether it's run, walk, whether it's walk, whether it's running. But you also get timed at a park run. And I've often wondered, is timing it a good idea or not? Because loads of people who suffer with mental health problems, park run is actually what really, really helps them. That strong sense of community, you're moving, even if you're a volunteer at that park run, you still get a lot of benefits. But I want to then, when the timing comes in, and I'm not against it, I'm just sort of posing the question, does that start to make

us think about performance and taking us away from just doing it because it's a fun thing to do for some of us? Yeah. I mean, I think, I think, I think we, you know, there's so many different motivations that people have. And I think we need to, we need to embrace them all. Right. For some people, timing is great. It gives them a little impetus. It gets them, gets them, gives them, you know, you know, it helps them, you know, do a little better and, you know, challenge themselves. Other people find it defeating and, and, and, and, and, and off-putting. And, and so I think, you know, we should let a thousand kinds of physical activity bloom, right? And if, you know, there's never going to be one type, right? For some people, why not just dancing? I mean, I have a section in the book on dancing, which is-

You do, and I've got that written down to talk to you about because I didn't know that at all. So please do expand on that. It was a brilliant section. Yeah. I mean, every culture in the world, I find an exam an exception has has not only just dancing but endurance dancing as part of its as part of its culture you know people people dance for hours um in just about every culture and i even even in jane austen i found some wonderful quotes in jane austen and you know georgian england where people where people dance the night away, right? It's a way of making physical activity. And they probably didn't think of it as exercise.

It was social. It was fun. So there are many, many ways for us to get our bodies moving and to get the benefits, the mental health benefits, the physical health benefits. And I think we should, if we're going to be successful, we need to try to, you know, there's not going to be one size fits all approach, right? There's going to have to be many approaches. I mean, look, there are some people, as you know, because you read the book, throughout the book, I make fun of treadmills. Because treadmills are, for me, the apotheosis of exercise.

Here's a machine, you know, you have to spend money to buy it or spend money to go to the gym to use it. It makes you work hard to basically stay in the same place. You get nothing done. It's loud. It's noisy. The air has fed it. I put people on treadmills for a living, but I hate treadmills. I have one in my basement. I sometimes use it. So what some people do is they listen to a podcast or maybe this podcast or they'll watch a movie or whatever to tolerate the treadmill. And if that works for them, that's great. There's nothing wrong with that. It's actually very efficient.

You can do two things at once. You can listen to a podcast and get some exercise at the same time, but others just can't stand it. So let's not be judgmental. Any way that works is great. I mean, and we just have to support them all. is great. I mean, and we just have to support them all. I'm a big fan of individualized and personalized approaches. And I really like that idea that maybe we've got to broaden out what we recommend to people. Say, you know, it doesn't matter how you move your body, but you just want to move it more and find what actually works for you. But are there

any sort of universal principles when it comes to movement that actually do work for all of us? In terms of getting us to move? I mean, again, I go back to the simple, I mean, my, you know, I think there's sort of, again, two basic impetuses that have, over millennia, have been the basis for how and why people move. And one is because it's necessary. And the other is because it's fun. And for most people, fun involves social. So sometimes going for a run by yourself or a walk by yourself is meditative and it's nice to be by yourself and you can think through a problem. But for most of us, you know, we like to be with other people.

And so that's why Park Run is so successful. It's social. Here in Cambridge, we have the November Project. Every Wednesday, people do these wonderful runs and they run up the stadium and they do all kinds of great stuff. We have, you know, all around the world, there are various kinds of social events. There are, you know, dancing is social, playing a game of, you know, soccer or football is social. I mean, the list goes on, right?

And there are many ways to do it socially. And I think so that's critical. But that's never going to be enough for some folks. And, you know, exercise, physical activity used to be necessary in our lives, and that was the impetus that people had to get out every day and do work. We need to find ways without coercing them unethically to make exercise, to make physical activity necessary. Because we can't tell adults that they can't go to that, you can't, they can't have the benefits of society unless they exercise, right?

We need to help people help themselves. And I think the way to do that is through what's called a commitment contract. Just taking a quick break to give a shout out to AG1, one of the sponsors of today's show. Now, if you're looking for something at this time of year to kickstart your health, I'd highly recommend that you consider AG1. AG1 has been in my own life for over five years now. It's a science-driven daily health drink with over 70 essential nutrients to support your overall health. It contains vitamin C and zinc, which helps support a healthy immune system, something that is really important, especially at this time of year. It also contains prebiotics

and digestive enzymes that help support your gut health. All of this goodness comes in one convenient daily serving that makes it really easy to fit into your life, no matter how busy you feel. It's also really, really tasty. The scientific team behind AG1 includes experts from a broad range of fields, including longevity, preventive medicine, genetics, and biochemistry. I talk to them regularly and I'm really impressed with their commitment to making a top quality product. Until the end of January, AG1 are giving a limited time offer. Usually, they offer my listeners a one-year supply of vitamin D

and K2 and five free travel packs with their first order. But until the end of January, they are doubling the five free travel packs to 10. And these packs are perfect for keeping in your backpack, office, or car. If you want to take advantage of this limited time offer, all you have to do is go to drinkag1.com forward slash live more. That's drinkag1.com forward slash live more. So let me go again back to education. In education, we have education works on a commitment contract basis for adults, right? So I'm a professor in a university where people pay ghastly sums to go to Harvard, right?

I mean, I think the tuition is and room and board and all that costs like $60,000 to $70,000 a year. That's full. Of course, most students don't end up paying that. I mean, the vast majority get financial aid. So don't worry. Most of my students are not fabulously wealthy, actually. Many of them are first-generation students because we're lucky we have really good financial aid. But anyway, somebody's paying $60,000 to $70,000 every year for them to go to school. And there's some commitment from them to go to school.

And what are they doing? They're having people like me torture them, right? I make them take exams. I make them read books. I make them stay up late at night studying. And if they don't do well, I give them a bad grade, which, you know, which, you know, stigmatizes them for the rest of their life. And, and, and, but they do it willingly because, because they've signed a kind of a commitment contract, whereas, whereas they're paying money for me to make them do stuff which they know is good for them, which they otherwise wouldn't do for themselves. And we do all kinds of other commitment contracts in our world. And I think exercise should be part of that. We should find exercise.

So there's a wonderful program called stick.com. It's a website run through some economists. They used to be at Yale. I'm not sure if they're still at Yale, but you can basically pick either a stick carrot or a stick. Right. And I described this in the book because I found out about this because there's a friend of mine in San Francisco who was, who's been trying to lose weight and she gave stick.com, I think $2,000. So not a small amount of money. And every week, she agreed that she was going to walk a certain number of miles. And if she didn't get those number of miles in, and her husband was a referee, if she didn't do those miles, as affirmed by her husband, they would automatically send $50 that

week to the National Rifle Association. That's the big association that tries to prevent gun control laws in the United States. And she very, very much hates the NRA and wants to see guns. And she has never missed a week of her walking since she's been doing that. So she signed a commitment contract, put some money behind it. Now, that's a kind of extreme one. But there are other ways ways we can do it just through a friend. I mean, a lot of my early morning runs, I don't, you know, at 6am, I do not want to run. I promise you. I mean, nobody, I want to be in bed with my wife, right? But I often meet a friend of mine who's a cardiologist and he's at 6am and he doesn't want to be there either. But we kind of agreed the day before that we were going to meet each other at 6am

to go for a run. And usually we're just like irritated at each other. And we don't even speak for the first, you know, 10 minutes. And then slowly we warm up. And I'm never unhappy that I did that run at the end. But I did it because I coerced myself through a commitment contract. Yeah. Very, very practical and pragmatic approach. I guess what you're saying is that the way we've typically encouraged physical activity has been very prescriptive. You have to do this. If you don't do it, you're not really looking after yourself. You sort of have to rely. We're very much putting it down to individual motivation, individual willpower. And what you're saying, I guess, is that this is not working, right? We've not evolved to exercise. We're now living in a

society where we simply don't have to anymore. That necessity has gone. So you need to find a way to make it necessary. And the way you found of doing it is you're meeting someone. So you need to find a way to make it necessary. And the way you found of doing it is you're meeting someone. So if your buddy has gone to the trouble of getting up early in the morning and goes to your agreed spot and you don't show up, there is a bit of, you know, you have social pressure to show up, which is why so many movement programs talk about, you know, doing it with other people, right? Because if you're leaving it up to yourself to motivate yourself, there's going to be times. I know when I got into parkrun, I remember thinking at the time I wasn't really a runner, right? And we can, we can, uh, let me put it another way. I didn't perceive myself as a runner, whereas now I do, but I still went because I did it with my son

is reason one. Reason two is there was this big community there, this really friendly community at Parkrun. So I just had to make sure that my son and I were at the start line by five to nine on a Saturday morning. And if that was, if I got there, I would complete a 5k. But if I had to do that myself, even if I had to do that myself with my son, I bet you some Saturdays, we wouldn't do it. And so I think that accountability piece is, I think it's really interesting. Now you mentioned you're not a fan of coercion yet you write uh a very surprising certainly surprising to me you write about is it the swedish uh is it beyond the the swedish underwear sportswear manufacturer and i was mesmerized reading that story so i wonder if you could tell that

and because that's actually taking a quite a different approach right yeah i had so much funding that so i i was i was thinking about this you know because the last section of the book the last quarter of the book is really about how to apply the sort of naturalist of exercise to the modern world and i was interested in this idea of coercion and i wanted to see if i could find an example of people who are forced to exercise adults i mean we force kids to exercise in school but nobody nobody blames an eye at that because we force kids to do all kinds of stuff and think it's totally acceptable. Because children can't make up their – children aren't responsible for their own decisions, but adults are. And so I was searching throughout the world.

I was thinking about like monks in Asia who are forced to do things and whatever. And I wanted to – I'm very into participant observation. I like to try what I study. And so that's why I've tried barefoot running. And I've, you know, I tried it. I tried to chase animals on, you know, done races against horses. And, you know, I'm into that. I like, I like, we're going to come to all that, believe you may. I like to put myself in the shoes of the people I'm studying. And, and so I, I found on the web, a few articles about the Bjorn Borg company is a company in Sweden that makes mostly underwear, but other kinds of sports clothing. It's no longer,

actually no longer owned by Bjorn Borg, but it's, and, and, you know, you know, those companies have those like little contact me thing. So I, you know, late at night, I remember telling my wife, I'd found this company and I'd read some articles and she said, well, contact them. So I, night, I remember telling my wife I'd found this company and I'd read some articles. And she said, well, contact them. So I got on the contact page and I said, you know, dear Bjorn Borg Company, I'm a professor at whatever. I'm interested in this topic and I'm kind of curious to learn more. And I remember going to bed and saying to her, I'm sure I'll never hear from them. And then the next morning in my inbox was an email saying, come and join Sports Hour. Come anytime you want. We'll be

happy to show you. So I was on sabbatical and I had some time. So I got on an airplane and I went to, you know, they were very kind and they told me when to show up. So I showed up and they basically said I could talk to anybody in the company. And, you know, I had to go to sports hour because at Bjornborg company, everybody has to exercise. It's, it's, it's a requirement. And there's a sports hour every Friday at, I think it's 10 AM. And, and there's no excuses unless, unless you're injured or whatever, or something like that. If you're a board member, if you're a visitor, it doesn't matter who you are. If you sweep the floors, if you're the CEO, it doesn't matter. You go to Sports Hour. And so I went to Sports Hour, which is a really hard kind of CrossFit workout. It was great. It was exhilarating. And you could do it as hard as you want or as light as you want. And then they have all kinds of other events where they, you know, instead of a

Christmas party where everybody gets drunk, they run through the streets of Stockholm and have hot chocolate afterwards. You know, I mean, it's a, it's a delightful environment, but of course, you know, not everybody liked it. And some people left the company, but some people who are in the company love it. And I just talked to folks about it and see to see how it worked. And to my surprise, it was, it was actually pretty popular. And the people actually kind of realized that it was a beneficial thing. But I should also say, these are people who've drunk the Kool-Aid, as we say in the United States, right? Everybody who really hated it has obviously left the company.

You wouldn't be in that company if you didn't think this was acceptable. But the fact of the matter is, that's, as far as I can tell, the only company in the world that does that. And we're not going to find, that's just not going to work in most places. And we have to find other ways to make exercise necessary. What's interesting about that company for me, and you know, you're absolutely right, there's that inbuilt bias, isn't there? Because people, I guess some people, if they know that about the company, and that's not their kind of thing, they may not even apply for a job in the first place. If they start working there and they think this is a good idea, but then they feel it's too much pressure, there's some sort of

camaraderie that they don't like or they don't thrive on, they might leave. But it's an interesting model. And I appreciate this cannot be rolled out across society there's a kind of ethical point there I think as well but you know I wonder what you think about the ethics of that where a company says hey look we and again I'm not speaking for that company because I don't know the the ideology it. But let's say a company felt that, well, we know fiscal activity is important because it will help the employees, it will help them with their health and well-being, it's going to help them concentrate, focus, be more productive, it's a great way of bonding. I guess what would happen if companies

started to, some companies were like, well, this is part of the culture here. And if you want to work here, this is sort of what we would be supporting. It's quite a tricky one ethically, isn't it? Because it could be done in a way where it's very supportive. And it's like, well, if you just want to walk for that hour around the gym, that's fine. There's going to be no pressure on you from your manager or from the boss. You know, I know you'd have to demonstrate that there was no discrimination by doing that, but it's working there. I mean, could that be, you know, you're saying that we need to take personalized approaches. So, could that work for some companies?

Well, I mean, let's flip the question and ask, did that used to work for some companies well i mean let's um let's uh let's let's flip the question and ask did that used to work for some companies so so in the united states as in every every you know in europe um universities are kind of like companies and every university until recently required students to exercise in the united states physical activity physical education was a hundred percent you know Every single university in the country, Harvard included, required physical education. Wow. And going back to the ancient Greek philosophers and the traditions in India and China, everywhere in the world where you had educational systems, which of course were for elite people, right?

Because peasants didn't go to school, but wealthy aristocrats did. With no exception, exercise became part of people's education because people understood that there was a relationship between exercise and the body and the mind, right? Mental health and physical health and that exercise is good for students. And that was dropped in the United States and starting basically in the 70s. So Harvard, for example, got rid of its physical education requirement in the 1970s. And now, you know, we see the results, but these are adults, you know, these are 18 plus year old people and it was required. And so, you know, I think this is, and of course, until recently, everybody had to be physically active to get to work. They had to,

you know, walk to get to work. They didn to, you know, walk to get to work. They didn't have elevators to get them to their floor. You know, I mean, we could go on with all the things that have changed in the world. So we've kind of shifted our workplace and shifted our schools without shifting the kind of how we approach our bodies. And so maybe Bjorn Borg Company is going back to something very ancient in a new way. But, you know, the fact that we're so uncomfortable with it, I think is interesting. We're just so worried about coercion

and people's rights and for good reason. But we're also, I think, I think sometimes we, you know, we also, I'm gonna probably get myself in trouble now. But look, I think it's, as you can already tell, I'm very opposed to body shaming and fitness shaming, right? It's, it's unacceptable. But sometimes I think, because we're so worried about body shaming and fitness shaming, we, we go, we go to the extreme and basically turn off the whole system. Yeah. And, and I wonder if the, if, if we can't have our cake and eat it too, so to speak,

right. Can we find a way to help people be physically active without engaging in body shaming, without engaging in fitness shaming? And I think we can. And again, I'm going to go back to my commitment contract model, because if let's just say you're, you're unfit, you're overweight, you're struggling, you hate to exercise, but you want to, you want to get, you want to exercise. Now, if I told you, I had, you had to go to a CrossFit, you know, workout every week and, you know, do 150 burpees with

the, with this, you know, highly muscled, you know, you muscled nutcase in front of you who's your boss, you'd hate it, right? But if you could just walk 20 minutes a day, climb the stairs, right? Pick your own goal and work towards that that would fit your fitness level. You could do it on your own. you could do it with friends, etc. Not in a way that... We can find ways for people to be more physically active that can accommodate every disability, can accommodate every level of fitness, can accommodate...

But as a society, we've been very uncreative about it. We're not really willing to put in the time and the money and the effort to make it happen. Yeah. And I think a lot of people get put off by gyms, for example. They've sort of been sold this idea that gyms, if I want to get fit, whatever their interpretation of fit is, you know, I want to do my physical activity, then it has to be at the gym. It has to have a particular name. It has to have particular clothes that I wear, because if I don't, it doesn't count. And for me, as a doctor, I find myself trying to break down that barrier with patients all the time. I've often said, now I didn't know about these sort of tribes and these cultures for years who've

danced, but I've often said to patients, I said, look, do you like dancing? They go, yeah, I like dancing. I said, okay, well, let's start there. Why not, you know, just before dinner every night for 10 minutes, have a dance in the kitchen, put on the tunes and dance. Go, yeah, but do I need something more? I said, well, let's start there. And I've seen families bond over it. I've seen people's mood get better just from the act of dancing every day. And, you know, a lot of people are conditioned to think, oh no, it needs to have, you know, I need to go to this particular class and then I need to buy the latest outfit. Well, again, that's the commodification, commercialization of exercise, right?

It's now a product and you have to spend money on it and, you know, you have to, uh, you know, and there's some, there's people there to, to, to advertise to us that, you know, you can't run unless you wear these fancy shoes and you, you have to have your fancy watch and all this sort of stuff. And frankly, I enjoy fancy shoes and my fancy watch when I go running, but we don't need it actually. Um, and, and, and it works for some people, but it obviously is not working for the, for everybody. And so, yeah some people, but it obviously is not working for everybody. And so, again, I think we need to kind of step back from our Western medicalized, commercialized attitude towards exercise and take a broader view, a broader perspective. And if we just simply do

that, which is what my book tries to do, we'll come up with all kinds of other wonderful solutions. Dancing is just one of them. Going for walks with your, like why, for example, do we have so many boring meetings where we sit around in chairs or now we sit glued to our bloody Zoom screens, right? Why can't we get up and walk, right? And have meetings on the hoof, right? Can't we get up and walk, right? And have meetings on the hoof, right?

There's so many examples of ways in which we could just encourage physical activity in a way that'll make it both necessary and fun. Yeah. Now, Daniel, a lot of the research you did for this book has taken you to wonderful places around the world to do what sound like, from where I'm sitting, incredible things. In Tanzania, you've stayed with hunter-gatherer tribes. You've, I think, hunted kudu. You've ran with horses. And I'd love to sort of explore some of those

because these are things that many of us have never done. And I think there's something to be learned from that. So I was going to ask you, what has been some of the most surprising things that you've learned when you've gone and lived alongside indigenous tribes and communities? You've mentioned dancing. Did that surprise you? And was there anything else that you discovered that you didn't previously know? Well, I mean, I'm a really lucky person. I have a, I'm such a, you know, fortunate to have a great job that, you know, I get paid to go have fun and travel around the world and study things that interest me. I'm a ridiculously lucky person.

And I would say that, you know, what surprised me the most is really, I mean, quite literally, it's the story I tell in the beginning of the book, which is, which is that people in these societies don't think what they're doing is exercise. And for me, that was the spark that started this book. Because it was 2012, and I was finishing my previous book, which is called The Story of the Human Body. And in that book, the kind of message of that book is we didn't evolve to be healthy. And that book is about mismatched diseases, how the modern world that we live in is very poorly adapted to it in some respects. That makes us get sick in various ways. But so I was finishing up that book, and I went to Highland, Mexico.

So I went to the Ironman competition in Kona. This is a true story. I'm not exaggerating anything here. I was part of the medical conference that precedes this incredible race, which is just amazing. People do a 2.4-mile open water swim. Then they do a 112- mile bicycle ride across the desert. And then they do a full marathon in like 90 degree heat. It's insane, right? And the people who win, like do it in like a little over eight hours. I mean, they're, they're like cyborgs. They're not real human beings. Like, you know,

they're just astonishing. And then I got back, you know, working on the book, astonishing. And then I got back, you know, working on the book and then went to Highland, Mexico, where I hired a guy to help me go into really, really remote areas to study the Tarahumara who are sort of famous for their running. And, you know, I'd read about how they barefoot run and do these long distances. And what I discovered was that, first of all, I didn't see anybody running barefoot whatsoever anywhere. And I was traveling all over the place. And when I asked people about their running, they were like, well, people did run in these traditional races. But other than that, they didn't run. And I had this list of questions, being a good anthropologist. I had a questionnaire, which I had designed carefully. And one of the questions was, you know,

how do you train for your running? And my translator couldn't, you know, was struggling to figure out how to ask this question because there was no word for train in the Native American language, Romamuri. And so she was trying to, you know, you practice, you know, she was trying to explain to these, and there was this one 70 something year old guy she asked. And I remember him because he was really, he was really, he was, I don't know, maybe that 10th or 12th person I was measuring and studying. And he was kind of a very serious fellow. He was a runner, too, by the way. And the vast majority of people don't run very much. He was a runner, and he, through the translator, asked me, why would anybody run if they didn't have to?

And he, through the translator, asked me, why would anybody run if they didn't have to? And at first I was thinking, this question I wrote is really bad. I mean, I wrote the wrong questionnaire. And then I realized, actually, this is telling me something, that people there run when they need to. But exercise is just not part of their lexicon. Training is not part of their lexicon. Training is not part of their lexicon. And that kind of just permeated my brain as I started. I took every opportunity I could to do something.

I was in the Western Ghats. We were looking for barefoot runners. And we were looking for people who were running there. We had been to Greenland and to various places in africa etc you know every place i've gone i've noticed that people who are very physically active don't think of what they do in any way whatsoever as exercise um and to me i think that's the most surprising uh that was initially most surprising yeah i mean it's very powerful even though i've read that, to hear you explain it is very, very powerful because it gets to the heart of what the problem in society is about getting us to move more, right? It's like these communities don't have words for exercise or training. It just doesn't exist because it's, I guess it's necessity driven. Or it's, you know what's really beautiful?

The Tarahumara, when they run their long distance races, it's a form of Or it's, or, or, you know, it's really beautiful in the Tarahumara when they run their long distance races, it's a form of prayer for them. I mean, that's, to me, that's really beautiful. It's spiritual, right? They run because they believe it makes them closer to God. What if we adopted that attitude, right? I mean, it's such a beautiful thought, right? And it, and, and, and, and, and it does, right?

And for them, actually the concept of them, actually, the concept of chasing, actually, I have one of the balls over here, actually. This is one of the balls they use in their foot race. And when they chase this ball, the ball gets dirty, et cetera, and it gets lost. And for them, kind of the randomness is like a metaphor for life and for the vagaries of life. And it's really beautiful what they do. And that's true of a lot of the sacred dances that people do. And the list goes on. Would they kick that ball around and follow it? Is that what would happen?

Yeah, they kind of flick it with their foot as far as they can. And then they chase it and they find it again. And they flick it and they chase it and they find it and they flick it, and they chase it, and they find it, and they flick it. And they'll do this. There are two teams doing this, and they'll do it until one team laps the other in a course. And sometimes the race can be 10 miles, and sometimes the race can be 50 miles. And it depends on how they set up the race and what they agree on beforehand. And they're betting wildly.

So it's a big social event and it's fun, but it's also a form of prayer. Yeah. This is something I explored in a conversation with Sanjay Rawal, I don't know how many episodes ago, who he was the director on a film called 3100. If you've not seen it. I've seen snippets of it,

but I haven't had a chance to sit down and watch the whole thing. Having read your book, I think I can almost guarantee you would love this documentary because it's really, in many ways, showing tribes around the world how running is, you know, it is about transcendence. It's a spiritual practice. It's not for calories burnt, how many miles have I gone, you know, what did my heart rate do, all this kind of stuff that again, nothing necessarily wrong with it. It's to get them closer to, you know, I guess being at one with the world, sort of finding themselves. And it's really, really interesting that because the way we do it here in the West, by and large,

and of course, everyone is different, does seem to be quite far removed from that. It's interesting because you have been termed the barefoot professor in the past. And you mentioned when you went to Mexico, you didn't see that many people barefoot. I think you've been to other cultures like in Kenya and India where you have seen a lot of people barefoot. So what's the deal there? Well, there's a story behind it, if you don't, if you have time. I've got plenty of time and this is probably one of the things I'm most interested in. So, and I've got this sort of professor barefoot running in front of me. So you go as deep as you want here. So here's the story. So in 2004, Dennis Bramble and I published the Born to Run paper.

That was the title in nature, Born to Run. And it was fun. I got invited to give all kinds of lectures. And I gave a lecture the night before the Boston Marathon. I think it was 2005. And it was a dark and stormy night, literally. I mean, there was an incredible rainstorm that came in just before the marathon. Everyone was worried about, you know, the rain and all that. And it was a packed audience. And there was a guy sitting in the front row who I'll never forget him,

because I remember he looked kind of like a bum from Harvard Square. And he had socks on that were wrapped in duct tape. And he was very intent on the lecture. And afterwards he came up to me and asked, you know, if people evolved to run, um, um, um, you know, what did they run barefoot? And is there any problem with that? And I said, well, of course they ran barefoot because shoes were invented fairly recently. And, um, and you know, I don't know really very much about barefoot running. Um, but you know, and he, I started and I realized he lived in the area and he told me he was a barefoot runner and he said that he'd come to the lab. So at the time we were studying head stabilization. Now, when you run, when your body hits the ground, your head jiggles, right?

And we were interested in how the body stabilizes the head and how you prevent that jiggling from occurring so it doesn't blur your vision. And most of the runners we were looking at were heel strikers, right? They would land on their heel and their head would jiggle. And I remember there was a few runners occasionally would come into the lab and they would be forefoot strikers. They'd land on the ball of their foot and their head wouldn't jiggle as much. And I remember thinking, ah, they were like ruining my experiment. Because we're not getting the head jiggling we wanted to measure. And so this guy comes in and his name is Barefoot Jeffrey.

And he owns a bicycle shop here in the area. And he came in and we set up the equipment and he just ran, light as a feather. No head jiggling whatsoever. And he landed on the ball of his foot. And I asked him why he landed on the ball of his foot. And he said, well, it doesn't hurt. If you land on your heel, it hurts.

And so we started doing some experiments and realized that that's how people ran when they barefoot. You can't slam into the ground like you can in a shoe because you have all that cushioning in the shoe. You have to run lightly and gently. And so we got to studying barefoot running. And, of course, I've been working in Africa for many decades. And I've seen people in Africa running barefoot, but I never really measured them. So we went out and started measuring them and published you know, published another paper in Nature about the

biomechanics of barefoot running. But I always like to try what I study. And we realized that to me, it's not about whether you're barefoot or not. To me, it's about how you run. To me, running is a skill, just like swimming or climbing a tree or all many other things that we do. And there are better and worse ways to run. And what barefoot running does is that it helps us learn the skill of running. That I think there are advantages to not crashing into the ground and relying on some technology in your shoe to make that comfortable. And so to me, it's not about, you know, to me, I think, you know, you can run beautifully in shoes and you can run terribly in shoes and you can run beautifully barefoot,

you can run terribly barefoot. But what really matters is how you run and that barefoot running gives us information. And sure, shoes are comfortable. And I mostly wear shoes when I run. I also wear minimal shoes. And I also, I agree with everything you just said. You can't just throw away your shoes or transition your shoes and immediately change your gait. You have to transition gradually and slowly, and you have to learn the skill of running. But if you do, the evidence suggests that there's a lot of benefits and you don't destroy your knees and you can do all kinds of good things with your body. And, you know, there's a lot of evidence and there's mounting evidence, I think, that supports that. But, of course, it's still controversial because there's a lot of money in the shoe industry.

And there are people who like what they do and they get upset if you tell them that, you know, they should be doing something different. And, you know, for many of them, they shouldn't. You know, if it ain't broke, don't fix it. But many people are injured and they might benefit from changing the way they run. Yeah, I mean, that certainly echoes what I've seen in my clinical experience. And even a really good friend of mine, actually, who has very much been enamored with my journey to minimalist shoes, he sort of transitioned to pretty much everything apart from running until maybe six months ago. You know, he'd wear minimalist shoes for work, for walking,

for going out with his family at the weekends. And he really liked the connection it gave him. He sort of felt he was moving differently, but he said, I've got no real reasons to change the way I run because I can do it. I don't get injured, but something changed about six months ago. I think just on that journey, he was quite interested to go, well, what is it like if I actually try running? So he went super slow, you know, he could only do three or 4k, I think initially, but now he's, you know, he's, he's a badge wearing sort of barefoot runner. And I think, I think all these things become quite reductionist, don't they? It's like barefoot running, good or bad. Minimal issues, good or bad. It's like,

well, it kind of depends on the context a little bit, doesn't it? Yeah, absolutely. Before we get back to this week's episode, I just wanted to let you know that I am doing my very first national UK theatre tour. I am planning a really special evening where I share how you can break free from the habits that are holding you back and make meaningful changes in your life that truly last. It is called the Thrive Tour. Be the architect of your health and happiness. So many people tell me that health feels really complicated, but it really doesn't need to be. In my live event, I'm going to simplify health, and together we're going to learn the skill of happiness, the secrets to optimal health,

how to break free from the habits that are holding you back in your life, and I'm going to teach you how to make changes that actually last. Sound good? All you have to do is go to drchatterjee.com forward slash tour. I can't wait to see you there. This episode is also brought to you by the Three Question Journal, the journal that I designed and created in partnership with Intelligent Change. Now, journaling is something that I've been recommending to my patients for years. It can help improve sleep, lead to better decision-making, and reduce symptoms of anxiety and depression. It's also been shown to decrease emotional stress,

make it easier to turn new behaviors into long-term habits, and improve our relationships. There are, of course, many different ways to journal and as with most things it's important that you find the method that works best for you. One method that you may want to consider is the one that I outline in the three question journal. In it you will find a really simple and structured way of answering the three most impactful questions I believe that we can all ask ourselves every morning and every evening. Answering these questions will take you less than five minutes, but the practice of answering them regularly will be transformative.

Since the journal was published in January, I have received hundreds of messages from people telling me how much this has helped them and how much more in control of their lives they now feel. Now, if you already have a journal or you don't actually want to buy a journal, that is completely fine. I go through in detail all of the questions within the three question journal completely free on episode 413 of this podcast. But if you are keen to check it out, all you have to do is go to drchatterjee.com forward slash journal, or click on the link in your podcast app. Almost all the world's best runners have what I call a barefoot style.

And yet it's funny that some people get really mad. Like, you know, you tell me I have to be a forefoot striker. It's like, no, you don't have to be a forefoot striker. But, you know, some of the world's best runners are forefoot strikers. There's nothing wrong with it. So people are tribal, right? Just like in the United States, you know, you've got the Republicans versus Democrats, you know, forefoot strikers versus rear foot strikers. It's crazy. I think actually, it's interesting, people often ask me what kind

of shoes I wear. Well, I wear many different kinds of shoes. You know, today I wore one pair, but tomorrow I'll probably wear something other. Maybe Thursday I'll go barefoot. I mean, you know, why do we have to categorize ourselves and just do one thing? It's a fascinating insight. The other thing that's interesting to me about barefoot running is how out of touch we are with our bodies. A lot of people, the idea just makes them cringe. Like, are you serious? I mean, you're going to cut your feet.

What about all the hypodermic needles and glass out there? And, you know, I've heard it all. Right. And, and, and, and all these people haven't tried, they have no idea. And, you know, I think everybody should just try, just, you know, go for a few hundred meters, take your shoes off and run for just a few hundred meters down a street. Don't, don't, you know, make sure it's a smooth street and, you know, don't do it at night so you can see the glass and the hypodermic needles, depending on where you live, right? But you'll discover that it's actually kind of fun. But don't do too much too fast because you will injure yourself if you do too much too fast. But people are just out of touch with how their bodies work. I guess even just if people are lucky enough to have a garden or a backyard, you know, even just start by walking in your backyard garden and just get used to that feeling again. You know,

I've always, I'll tell you what, I've always, it's always fascinated me. So I, you know, my parents are immigrants from India to the UK. My dad came over in the early 1960s. And, you know, in Asian culture, certainly in Indian culture, you don't wear shoes inside the house, right? It's just not done. So I grew up, we never wore shoes inside the house. We'd always leave it outside or in the porch. Then you go in either in your socks or barefoot. And it's only, you know, when you get older and you start interacting with your friends and go around to their houses, you go, I remember thinking, oh, well, these guys wear shoes in their house. Oh, wow. You know, because my norm was that you don't wear shoes in your house. And it's just interesting how culturally things are different. I'm not saying that necessarily plays out as we get older, but

it is interesting that I've certainly noticed in some of my friends growing up, one of my best mates in particular, I remember he, you know, even at university going around, he'd always like getting ready in the morning, having a shower, shaving, would be putting his shoes on even if he was inside the house. And I guess culturally, these things are different. I remember going to India every other summer when I was a kid. We used to go to a city called Kolkata or what used to be called Calcutta for six weeks. And I remember playing with my cousins and my cousin, who's about four years younger than me, he'd always want me to come and play football. And we'd go down to the apartment, just underneath

all the apartments, there was a bit of land. And they were all playing barefoot, like properly tackling, you know, going in hard. And I started playing it, I found it really difficult at first, but by the end of the summer, you're used to it. So it's different everywhere, right? In terms of how much they actually wear shoes. Right. Yeah. I mean, I've also had those experiences. I don't, obviously haven't gone to India as much as you have, but I've had those experiences. And actually one of my favorite moments was playing, I didn't make it into the book, but I've had those experiences. And actually one of my favorite moments was playing, I didn't make it into the book, but I remember playing cricket with a bunch of kids in a tiny little village in the Gat Mountains. And what was terrifying was not being barefoot. It was those

bowlers. Boy, they were terrifying. But the way in which we, but you used a very important term there, which is this cultural, these cultural ideals. And they translate into so many other ways in which we use our bodies. So another example is sitting or sleeping, right? The idea that one of the Western ideas we have is that you should sleep in a quiet, dark room with a soft, comfortable mattress with nobody around you and no sound and no light and no nothing. This kind of stimulus-free environment, that's a cultural norm too, right? And until recently, even in the West, nobody did that, right? And yet people feel like they can't sleep properly unless they're in that kind of environment, which is, again, it's what you get used to. It's a cultural norm. And then if you're

not in that kind of environment, then you get stressed and your cortisol levels go up because you're anxious about sleep. And of course, that prevents you from sleeping in the first place. How we sit, like we're told, you know, we have to sit in a chair with a particular posture. That's also a cultural norm. That's completely made up in the 19th century by German orthopedic surgeons who, for some reason, opined that when you sit, you should have the same curvature in your spine as when you stand. There's no evidence to support that whatsoever. It's completely made up.

And in fact, there's plenty of evidence that doesn't support that. I could go on. We have all kinds of cultural norms that we, there's nothing wrong with them because you can't not have a culture. I mean, we all grew up in a particular culture, but sometimes we need to step back from what we're told and question it or ask, you know, does that work for me? Particularly in our modern world in which often it doesn't. Yeah, so, so fascinating.

Well, let's go into some of these norms or myths. Like you sort of bust quite a lot of myths in this book. We mentioned running a bit. So let's go in there. Running, you know, even within the medical profession, people will say that running is bad for your knees. I'd love you to expand. Poppycock. Okay. I don't know if I'm allowed to say that. But look, running injuries are common, right? I mean, when people do any exercise, they'll injure themselves. And running can be very repetitive, right? You know, thousands and thousands and thousands of steps with high forces.

And yes, people do injure themselves. And yes, the knee is the most common sign of injury. But we already talked about this, that I think running is a skill. And if you actually learn to run properly, the forces and that we actually know from a biomechanical level, as well as even epidemiologically, that proper running form can decrease the rate of knee injury. But the chestnut of all those injuries, of the myths, is the idea that running causes arthritis of the knee. We've actually done a lot of research on arthritis in my lab and the evolution of

arthritis. It turns out, by the way, that your chances of getting arthritis for a given year and your age have doubled since World War II. Doubled, right? And that's clearly not because genes for arthritis have swept through the population. It's because our lifestyle has changed. And we're trying to figure out what that's about. And it's not about being more physically active because people have become less physically active today. And it turns out that running is actually healthy for your knees. And actually, it's good for cartilage growth. It actually keeps the cartilage healthy as you age, physical activity does. And there have been maybe 15 randomized control studies showing that runners do not have higher incidence of knee arthritis.

And yet, I can't tell you how many physicians I've spoke to who just assume that with no evidence. Zilch. They just say it because it's a cultural bias. And then they have the authority of being a physician. But they're wrong. It's just flat out wrong. And it can be disproved. And the problem is, can I say, one of the problems is there's a wider problem here, I think, which is we're so far removed from our evolutionary heritage

or evolutionary norms compared to these modern societal cultural norms that I think we've become very, we're so risk averse when it comes to physical activity. Anytime we talk about it, we have to give disclaimers. We have to say, yes, be careful when you do that. Every time I submit a book manuscript, the editor's coming out, you know, just make sure that people aren't going to get injured and do this. And I understand it because of course no one wants to get injured, but we've made something that is fundamentally part of our human nature to move our bodies. We've turned it into something that's quite removed from us. We have to be careful. We need to keep our back like this. And again, please, I'm not trying to say that

those things don't have merit for some people. I just really feel, very much like you said, we've commoditized it. We've made it feel like it's this thing that's separate from the rest of our lives. And I think that's really problematic. Well, another example is sleep. I mean, one of the things I, so when I wrote this book, I thought, if I'm going to do a natural history of physical activity, I better start with physical inactivity, because after all, it's two sides of the same coin. And I've been very interested in sitting for a while, and I've studied sitting for a while, but I didn't really know, I'd not really delved into the sleep literature. And I was astonished as I started looking at the sleep literature, that this idea that you need eight hours is also just made up as far as I can tell. There's

actually no empirical evidence for it. I mean, some people do need eight hours, but it's been oversimplified and over commodified and imbued with kind of cultural significance. So it turns out when we look at people in parts of the world who don't have electricity, they don't have internet, they don't have iPhones, they don't have, you know, telephones, they don't have anything that has electricity, right? They don't sleep eight hours. They actually sleep between 5.9 and 7.1 hours. I think that's the, I can't remember the exact numbers, right? And furthermore, when you look at epidemiological studies of very large samples of people, in terms of relative risk of heart disease and various other illnesses, the optimum always comes out to seven, not eight.

I mean, of course, there are some people out there, because there's variation around the mean, who do benefit from eight, but there's some people who get by at six. But somehow we've turned eight into this kind of this ideal. And then what happens is that people feel like, oh my gosh, I'm not getting eight hours of sleep. There's something wrong with me. Then they get anxious. And of course, when you get anxious, you produce cortisol, which makes you stressed. And cortisol is the enemy of sleep. And we create this kind of feedback loop, which then gets people to go buy drugs to make them sleep or spend ridiculous amounts of money on some clip go buy drugs to make them sleep or spend ridiculous amounts of money on some, you know, clip on their nose that helps them sleep or, you know, whatever it is,

you know, curtains or new mattress or whatever. And, you know, none of that, you know, we've created a sleep industrial complex based on a cultural norm that's kind of Western and modern, but not necessarily rooted in our biology. Yeah. And I guess it's one of the problems, really, one of your central arguments is that there's no one size fits all, right? We're all different. We all have to find what works for us, what's going to get us moving, I guess, what's going to get us sleeping. And some of us, I guess, you know, I would just add from a clinician perspective that I found that you can't really make these hard and fast rules for people because the individual in front of me, there are so many other inputs going on? And therefore, their sleep requirement is going to depend on all those things. Whereas some of these communities, let's say without electricity, without iPhones, maybe, I'm just hypothesizing here, maybe their stress levels are really,

really low. Actually, maybe they can get by with less sleep than somebody who has huge amounts of stress. Obviously, I can't say the answer to that. I'm just hypothesizing that it is quite individual, right? Of course. Of course. Yeah. And we sort of miss that. So sleep, there's a myth there. Running is good for the knees, of course. So I'm just trying to play devil's advocate. If someone listening to that goes, okay, I hear what you're saying, Professor Lieberman, but every time I run, I get knee pain. So what should I do then?

Well, I mean, well, there's two possibilities. One is you should back off because pain is an adaptation. It tells you something's wrong, right? And you shouldn't ignore pain. And if you have pain, you have to either, you can either treat the cause or you can treat the symptoms. So the question is, what's causing that pain?

And one possibility is you do already have damage in your knee, in which case running will exacerbate it. If you already have arthritis in your knee, running is not a good idea because it's going to exacerbate it. But the other possibility is that the way in which you're running is causing you to get the knee pain in the first place. And, and maybe you should, instead of, and you know, so many people go to a sports medicine doctor who will look at their knee, but never look at how they run. Yeah. Right. They're treating the symptom rather than the cause. Now, you know, these are things, there's no one answer to it. And I'm not saying that, you know, barefoot running is going to solve everybody's running problems. But, but you might want to look at how you run. And it might be that there's a better way for you to run that might actually alleviate the repetitive stresses that you're putting on the tissues around your knee that might be causing

the running pain. But you know, there's no one size fits all answer. Yeah. And it is a skill. And I think maybe, I'd be interested to see what happens with kids like my kids have never really worn cushioned shoes like from a young age particularly my daughter they've gone straight to minimalist shoes so i don't know if you would make a of course they're not necessarily learning the skill of running but they're also not wearing cushioned shoes to start them changing their gait accordingly so i don't know have you got any research as to what might happen to those kids who've never worn cushion shoes in the first place? Well, we've been studying that in Africa for ages, right? So we've got lots of data.

We've published many, many papers on kids who've grown up never wearing shoes and comparing them to kids from the same tribe who do wear shoes. And what we've not done, and what's really hard to do, is a randomized control study where you randomize people into wearing shoes and not wearing shoes.

As you can imagine, that's a challenging study to do, especially in a place like Boston where it gets very cold winters. But yeah, in my lab, we've published lots of papers. We have a paper coming out I think today in Nature Scientific Reviews on toe springs, that upward curvature in almost every shoe that exists on the planet, including many minimal shoes, and how that changes the biomechanics of the foot. So we're very interested in how shoes affect foot function and how that affects how we walk and how we run. We had a paper last year in Nature which showed about how calluses work, how calluses protect the foot, but how they transmit all the the the the sensory information from the ground to the body so unlike a shoe which is a trade-off between protection and and sensory information

calluses don't have that trade-off which is really interesting but so yeah this is a subject of of intense research in my lab we so so removing calluses, as is a modern trend to do for cosmetic reasons, could be problematic. You're saying that calluses actually give us that sensory information that we need. Yeah, well, calluses also come from just, you know, calluses come from being barefoot, right? The friction and the pressure of being barefoot, you grow calluses, right? And so most of us who wear shoes have very thin calluses, but people who are barefoot have thick calluses. And it turns out that thick calluses, I learned this when being barefoot, which is that, you know, I would step on something and I'd still feel it just as well, you know, as after my calluses had grown than when I, you know, because every winter, of course,

I'm wearing shoes. And then I often take my shoes off in the spring after the Boston Marathon, and I sort of slowly regrow my calluses. And I've noticed that as the spring and the summer went on, I would step on the same pebble or a similar pebble, and I would feel the pebble just as much, but it didn't hurt. So it wasn't that I was losing sensory information. I was just getting more protection. And so that started a project to study how calluses work. Because after all, until recently, everybody, we, that started a project to kind of, to study how calluses work. Cause after all, you know, until recently, everybody that was there, we didn't have shoes. We just had calluses and, and my dog, you know, she goes barefoot all the time. Um, I, one of my favorite moments was, uh, I was running barefoot, uh, a few, few blocks from

my house. And there's a woman I see all every morning, you know, or many mornings walking her to just two beautiful dogs.. I remember one morning I was running by her on my way to the river here, and she said, you're barefoot. I said to her as I whizzed by, your dogs are barefoot. The look of shock on her face, like, oh my gosh, my dogs are barefoot. But the dogs don't mind. Right. And our ancestors didn't mind people in all over the world don't mind. I'm not saying that shoes are bad or whatever. We shouldn't wear shoes, but you know, shoes change how, how our bodies work. And, and, and, and there's nothing, you know, judgmental about it. Nothing wrong with wearing shoes. There's nothing virtuous

about being barefoot. Um, but we, you know, we learned something about how biology works by, about being barefoot. But we, you know, we learn something about how biology works by studying people unlike us. Yeah. Super, super interesting. A couple more myths I'd just like to go through before we wrap up, Daniel. You mentioned earlier on in our conversation that hunter-gatherers sit down for long periods of time. So there's this idea that sitting is really bad for us. What would you say to that? Well, I mean, you know, we, again, oversimplify things, right? So you and I are sitting while we're having this conversation and sitting is the new smoking. So we might as well just be smoking a pack of cigarettes, right? And it is true that people who are physically inactive do run into trouble.

But it turns out that sitting is a completely natural thing. And again, we pathologize something that's natural. Recent studies have shown there's a guy named Dave Reikland who did a study of the Hadza hunter-gatherers in Tanzania, and they sit almost 10 hours a day, which is basically the same amount as Brits and Americans sit. So sitting isn't something weird and abnormal. But that said, how we sit is a little bit different. Yeah, I was going to ask her that. How do they sit?

Two important differences. The first is that many of us sit in chairs with backs. So I have this nice back in my chair. But when I sit with that seat back, that's a very modern thing. I no longer have to use any muscles to kind of keep my back upright. And that leads to a weak back, which we think is related to lower back pain. The other thing is that people in non-Western societies, and some people in Western societies, have a lot of interrupted sitting. They just don't sit inertly for hours and hours and hours. And it turns out that getting up every once in a while, every few minutes, every 12 minutes or 15 minutes or 10 minutes, whatever, depends on the study, has all kinds of metabolic benefits.

It's like turning on the car engine. It turns on all kinds of cellular machinery. It lowers blood sugar levels. It lowers triglyceride levels in your blood. It decreases inflammation. it lowers blood sugar levels, it lowers triglyceride levels in your blood, it decreases inflammation. So you might sit the same number of hours as the next guy, but if you get up every once in a while and just move a little bit, that has all kinds of metabolic benefits. And then finally, maybe most importantly, it's what you do when you're not at work, right?

If I sit all day at work because I have a nine to five job and then I go home and then I sit in front of the TV, I'm in trouble, right? But if I sit all day at work, but I go to the gym in the morning and, you know, go for a walk and, you know, do some exercise, et cetera, it's not the same thing. And it turns out that when people do epidemiological studies of sitting time against illness, it turns out that leisure time, physical inactactivity is far more predictive of health than work time and so we don't often make these distinctions so so sitting isn't in and of itself abnormal or dangerous or bad it's how sitting fits into our overall life and how we sit um that is important i think that's such a great distinction and how we sit is, is, is fascinating to me because,

um, you know, sitting in these chairs, or I guess what we're saying is the more comfortable our chair is in some ways, the more problematic, because we can have hours without actually activating muscles. We can just sort of, we can just sort of morph into the chair and not do anything. Whereas I'm guessing the hunter gatherers don't have an alarm or a smartphone telling them to get up every 12 to 15 minutes so i'm guessing they're sitting in a way that i wouldn't say is uncomfortable well how do they sit why don't you explain how is it that they're sitting half the time they sit on the ground with their legs out maybe 15 of the time they squat you know another 15 of the time they squat, you know, another 15% of the time they kneel, you know,

but, but they're always, you know, there's children running around, there's food on the fire. There's, you know, they get up every once in a while, but they're not sitting there glued to their zoom screen because they're, because they're locked down in a pandemic or they're not watching a, you know, a two hour movie or whatever. They're, they're kind of getting up all the time. And, and, and we know both epidemiologically, but we also know in terms of the mechanistic biology that interrupted sitting is just way more healthy than uninterrupted sitting. And while there's nothing wrong with sitting per se, if that's all you do, then yes, you're going to increase your chances of a wide range of diseases.

then yes you're gonna you're gonna increase your chances of a wide range of diseases yeah and i'll just admit one of my own personal bugbears is a kind of societal norm which is to tell children to keep their bums on their seat and not move around it's something that it's so wrong yeah it's like you know it's like you're being a good obedient child if you sit there and don't move, which is just completely, you know, it's so far removed from our innate needs and wants, you know, but I watch my kids, they want to move around. My son actually in his old school, he used to get told off because halfway into the lesson or 10 minutes in, he'd like, he'd want to squat on his chair. He just felt very natural and comfortable in that position. And he's like, bum on chair, stay still. And I'm like, and I was really conflicted

because I'm like, I really thought, but that is, I don't want my son having to have his bum on his seat and stuck there for 40 minutes. But it's, I think this is where your book, I think is going to be incredibly helpful for society at large and just really busting a lot

of these myths, having a bit more nuance in the conversation around physical activity and movements, which I think is very much needed. I think it's such a fabulous deep dive into a topic that frankly affects all of us. I love the bit about grandparents in the book. Thank you. That's my favorite section. I loved the bit about grandparents in the book. Thank you. That's my favorite section. It was such a wonderful bit to read about.

And I wonder if you could just sort of expand on it and why it's so important for us to remember. Because many people, I think, as they get older, think that they should actually become less active. And you're sort of saying that may not be the case. Yeah, this is something we're working on further right now. But to me, I think it's maybe the most important part of the book in a way, which is that we have this idea that as you get older, you know, it's time to kick up your heels and, you know, move to Florida or whatever it is, right?

And just kind of be less active and take it easy and, you know, enjoy your retirement. But, you know, humans are unusual species. We evolved. We're one of the few species that evolved to live after we reproduce. We evolved to be grandparents. But we didn't evolve just to be grandparents, you know, to enjoy our grandchildren. We evolved to be grandparents to help our grandchildren. So if you look in the hunter gather societies and in farming societies, grandparents are out there foraging and hunting and gathering and digging and doing all kinds of stuff and helping out their children and their

grandchildren, providing food surplus, you know, helping, you know, being active. And in fact, we have data showing that people tend to be often are more active when their grandparents than when their parents, because they don't have kids in tow, right? And what's important about that, it's kind of like a chicken and egg question, you know, which came first, living long in order to be active or being active in order to live long. And, you know, they're both there, right? And it turns out that physical activity is really important in slowing processes of aging and decreasing disease. Because when you're physically active,

you turn on all kinds of repair and maintenance mechanisms, right? So when you're active, you stress your body, you produce reactive oxygen species, you generate heat. You turn up your sympathetic nervous system, your fight and flight nervous system. But then you spend energy after you're exercising to deal with all that, right? We produce antioxidants.

We produce molecules to fix all the proteins that we damaged because they got affected by heat. We lower our blood temperature. We turn on our parasympathetic rest and digest system to lower sympathetic activity. We turn on all these mechanisms that keep our bodies repaired and maintained. And the trick is that because we never evolved not to be physically active, we never evolved to turn on these mechanisms in the absence of physical activity. We need that stress to mount the anti-stress response. And so physical activity, this is really at the heart of the book. This is why physical activity is so good for us. It turns on all kinds of good processes in our body that keep us from aging and

keep us from getting sick. And so as we get older, that becomes even more important, right? You want to keep your muscles healthy. You want to keep your chromosomes healthy. You want to keep your cells from deteriorating. You want to keep the mitochondrial numbers up on your muscles. The list goes on and on and on. And that's why physical activity is so important. So as we get older, it becomes even more important to stay physically active because that, and of course, the data are there, we know the epidemiological data, we know the mechanistic data, but we don't have this sort of cultural idea that as we age, that's the time to keep up the activity, not turn it down. Yeah. It's really fascinating how we've evolved to be grandparents. I really like that as an idea.

really fascinating how we've evolved to be grandparents. I really like that as an idea. You've also mentioned in the book that we've not evolved to be too strong. And I found that really interesting. And it made me think of something that I guess I've been pondering for a while as with this, with this sort of narrative around exercise. And, you know, as a guy, you know, seeing since I was 13 or 14, seeing men's health on the magazine, wherever I went with a ripped guy on the cover showing off his six pack and his pecs, and being quite influenced by that, I think as a, you know, as an insecure teenager growing up, you now see there's some, you go into gyms and you see some you know really really muscly people who who love bodybuilding and I've actually had a few patients including one when I made a BBC documentary this chap who actually had body dysmorphia and he had a real

negative self-esteem issues how he viewed himself and, you know, working out, putting on muscle was, was absolutely linked to that. And I just want to, before you answer this, I just want to draw a contrast. A couple of summers ago, I was in a place called Chamonix in France, which is at the foot of Mont Blanc. Beautiful place. I was there in the summer with my family. I've got a lot of friends there. And one day we went to the swimming pool, the outdoor swimming pool. And what was really interesting to me is that if you looked around in the pool, it was so noticeable to me that the physique of people in the pool, whether they were, you know, above the age of 60, 70, you know, in the middle age, young, the physique of people was just a little bit different. You never saw, not everyone, but a lot of people look really fit, but not in a

like a really, I've worked on my fitness way. So these typically would be people who live in the mountains. So they're getting around, they hike at the weekends, they might go cycling, they make lug stuff up and down the mountains. It was almost like a functional fitness. They weren't working on being fit, yet they were actually really fit. And I think in some ways that actually supports everything you're making the case for in the book. So just a few thoughts there, I wonder if you could unpack them for me. Well, I mean, to me, for me, the big surprise is going to a gym and realizing, or I have a tiny little gym in my basement and i've actually gone i've bought weights whose sole function is to be lifted if you think about it's kind of really

weird thing right try to explain that to your great great great grandparents that you'd go out and spend hard-earned money on something whose sole job is to be lifted like why not just do some sit-ups or pull-ups or, you know, go out and do something in the garden, right? It's a very modern thing, right? And again, there's nothing wrong with it. I've done it myself. But we have this idea that, you know, of being ripped and buffed.

And a lot of this happened in the book. I went into the history of this kind of modern, you know, physical culture. A lot of it started in the Industrial Revolution as the machines were replacing humans. And people were insecure. And I think that led to Charles Atlas and this kind of rise of this physical culture movement, this idea of being really ripped and buffed and, you know, Mr. Universe kind of stuff. And we have this idea that, you know, to be, and there's nothing wrong with being really strong. I mean, for many folks, it's fun and so many people really enjoy it, but it's a modern

thing, right? And our ancestors not only didn't do that, but they couldn't afford to do that because muscle is a really expensive tissue. If you add a lot of muscle mass, you have to eat a lot more too. And in a world where food is scarce, you can't afford to have that kind of extra muscle mass. Furthermore, you don't have nautiluses and other machines that apply constant loads, no matter what the angle of your biceps are, et cetera. There is no way to kind of get that fit in a normal world. So again, it's important to stay strong as you get old, particularly to avoid muscle wasting, sarcopenia, which is a really serious disease of aging. People have a hard time getting out of chairs and stuff like that because they lose strength. But we don't need to be super strong to be healthy. And our ancestors weren't super strong.

So if you want to go to the gym and get ripped, fine, that's perfectly okay. Or if you enjoy, you know, looking at people whose physiques are ripped, that's fine too. But let's not pretend that this is a kind of a necessary, natural thing. And the other thing I think is that I worry about sometimes is people get really into what they do, right? They're aerobic people who do cardio who hate doing weights and people who do weights who hate doing cardio. And then they kind of self-justify what they do, right? And the answer, of course, is that we evolved to do a mixture of those things. Cardio still is the bedrock of most fitness programs. As a physician, I'm sure you would know this better than most. but if you really were to do one thing to kind of work on your physical, your health, cardio is probably it, but you should also add some weights in there too. I mean, that's also important. And some kind of mixture is what

we evolved to do, and it's probably right. And if you want to do more of one, more of the other, that's fine, but let's not pretend that's what we evolved to do we didn't evolve to be like super jacked you know caveman you know charles atlases any more than we evolved to be you know elliot kipchoge's we're evolved to be something in the middle yeah and i love your approach um damn it's very so respectful of people's autonomy that their right to choose it's like look you do it look i'm going to present you the science i'm going to present you the evolutionary story here yeah if you want to do something different go for it but let's not pretend it's anything other than that's your desire that's your passion i think that's that's a lovely way to approach it as we sort of close this conversation off i do

think we should briefly touch on the immune system oh yeah i because especially in view of what's been going on in the world a lot of people are thinking about their immune system because especially in view of what's been going on in the world a lot of people are thinking about their immune system how does physical activity play a role in the immune system yeah well um um as i was actually doing the the edits on the book uh you know the lockdown had started and i and i and i and i i made sure that there was a section on respiratory tract infections. But the immune system, like every system of the body, is affected by physical activity. And for the most part, just like everything else, it's improved by physical activity. And we don't know exactly why, but I think it's because if you're in camp and doing nothing,

and you don't leave, you don't encounter new pathogens, right? So I think there's a link between physical activity and immune function, because being physically active was the way in which we left camp and got exposed to pathogens. That might be a hypothesis. And it's also part of the sort of repair and maintenance mechanism. But there's plenty of data which shows that physical activity, moderate levels of physical activity, upregulate key components of the immune system. So for respiratory tract infections, for example, when you're physically active, you not only produce more immune cells, like there's natural killer cells, which I love the name, right? You know, they're naturally killing things in your body. They kill, for example, cells that come infected with viruses, right? right you know they're they're naturally killing things in your body they're they're your they kill

for example cells that come infected with viruses right cytotoxic t-cells again an important part of your immune system upregulated by physical activity and not only there you produce more of them but there's compelling evidence that you redeploy them to vulnerable parts of your body so when you when you go for a run not only do you produce more of these cells but you send them to the the lines of your respiratory tract which is, guess what, where we're vulnerable to COVID, right, to this SARS coronavirus. In addition, physical activity upregulates the humoral in your system, the antibody production. As people get older, their antibody production declines, but people who are more physically active have much healthier responses to vaccines

and produce more antibodies, and again, for the same reason. And so, by being physically inactive, we increase our vulnerability to directly increase our vulnerability to respiratory tract infections. But physical activity also has indirect effects by making us more likely to be obese, to have metabolic syndrome, to have all the hypertensive, which are all the covariates that increase your risk to disease. So if we're going to fight this pandemic, one of the key ways to keep ourselves healthy is to stay physically active. That said, there's interesting evidence and there's a big debate about whether too much activity opens a window and makes you vulnerable. And to be honest, there's interesting evidence and there's a big debate about whether too much activity opens a window and makes you vulnerable. And to be honest, there's not a lot of data because there's so few people who do too much.

We just don't have a lot of data at that end of the curve. And it's still very debated. So within humans, there's not a lot of really good data. But in animal models, there certainly is. So there's a site in the book, a study that is really quite extraordinary study. They gave mice a really virulent form of influenza. And then for the few days while the mice were coping with that influenza, you know, before that symptoms emerged, while their immune system was initially dealing with it, some of the mice were sedentary. Some of the mice that had

them exercise like 20 minutes a day. And some of those poor little mice, they had them exercise like two hours a day. And the ones who exercised moderately had less than half the mortality rate of the sedentary mice. But the ones who exercised ridiculous amounts had much higher mortality rates than the sedentary mice. And to me, I think that highlights, I think, what every physician knows, which is that, you know, some is good, but be careful, don't overdo it, because you're going to deplete your body of energy. And that then if there's less energy than your which in your immune system takes a lot of energy, you could potentially harm yourself. So, so, so really, as we deal with the physical problems, the physical health, the mental health of this, this, this pandemic, but also just our, our immune health, you. Staying physically active is

just absolutely crucial right now. Yeah, thank you. That was a really nice summary of the research there and sort of how it helps. Daniel, look, thank you so much for your time today. Thanks for writing such a wonderful book. I'll always like to finish off conversations with some practical tips for people. So the podcast is called Feel Better, Live More. When we feel better in ourselves, we're going to get more out of life. And I'm sure, you know, when we move more, when we move in a way that makes us feel good, that allows us to move regularly we're gonna probably live longer and we're gonna feel better in ourselves so do you have a few sort of practical tips for people so they can think about

and start applying them into their lives immediately to start improving their health and well-being well i think i'm i think the tip would vary depending upon the kind of person so if you're somebody who's struggling to get enough exercise, or if you don't get enough and you'd like to exercise more, I think that there's lots of things you can do. But I think the most important thing is to find somebody who you want to exercise with. Get an exercise buddy and use each other to help each other. There's nothing like having somebody who you meet for a walk or a run or whatever, and don't feel like you have to, you know, you have to go crazy, you know, some is better than none. And, and, and once you get better, you enjoy some, then you might decide

that you want to do a little bit more, but don't feel like there's an optimal kind of exercise or you, you know, whatever, just, you know, that you have to do it. Don't make it, you know, don't make it unfun, make it fun. And if you make it fun and make it part of your life and recognize also that your body has to adapt, it takes time. One of the problems, for example, of being obese is that you have less dopamine response to exercise. And dopamine is the molecule that makes you want to do more. It's the reward molecule. And obesity actually down-regulates that. And so we have these expectations that all of a sudden you exercise and a week later, you're going to feel great. Well, it's going to take more than a week and you have to be in it

for the long-term, not the short-term. And so don't do it just for the health benefits, do it for the social benefits, do it for all the other things. And if you make it fun and part of your life and find ways to make it necessary, I think that's the most important thing that we, you know, that's the most important tip. And there are so many ways to do that. I, for example, leave my exercise clothes out in the morning when I go to bed

so that when I wake up, that's what I put on. And that like helps, it's like, it removes one less barrier to starting my run. Because I never want to go for a run in the morning when I start, never, ever, on no occasion my run. Because I never want to go for a run in the morning when I start. Never, ever. On no occasion whatsoever do I ever really want to start that run. And how many marathons have you done now?

I just did my 25th. Well, first of all, congratulations. But that, I think, is so valuable there at the end, what you said, Daniel, that you've had to find ways to remove barriers to that because you don't want to yeah yeah you've just completed your 25th marathon you don't want to get up and go for a run yet you are a runner right and that's really that's really really key isn't it i i know there's never been a time when i left the door of my house thinking, I really want to run. I always like, I'm going to force myself to run.

And then I always enjoy it when I come back. Another example is in my building, right? I live in my office when I get to go to it again after the lockdown. My office is on the fifth floor of this beautiful old Victorian building. And every day when I walk into the building, I want to take the elevator. Bar none. I always look at the elevator longingly. But the reason I don't take the elevator is that if anybody sees me taking the elevator, they'll call me a hypocrite. And so it's not because I'm doing it for my health. I'm doing it because I've socially coerced myself into taking the stairs.

And I never regret having taken the stairs by the time I get to the fifth floor, but I always regret taking the stairs as I head up the stairs looking longingly at the elevator. And don't beat yourself up for those instincts. Those instincts, even though elevators never existed in the Stone Age, it is a completely normal natural instinct to want to avoid exertion and don't ever feel bad about it. Yeah, wonderful closing thoughts there. You have found a way to make it work for you.

Certainly that's what all of us individually have to do. We've got to find a way that works for us, that we can be more physically active. Daniel, thank you for your time today. My pleasure. Thanks for such a wonderful book. And I look forward to the next time we get to have a conversation. Thanks. Great interview. I really appreciate it. That concludes today's conversation. I really hope you enjoyed it and that it has made you reflect a little on your own relationship with exercise. Now, was there something you heard today that really resonated with you? As always, my advice would be to keep things really simple

and try and take one thing from today's show that you can implement into your own life. Inspiration and ideas are great, but only taking action will actually lead to change. Of course, please do let Daniel and I know what you thought of today's show on social media. And you can see the show notes at drchastji.com forward slash 128, where you'll see links to all of Daniel's books, including his new one, Exercised, and other articles about his work. Now, for me, a really interesting part of my

conversation with Daniel was when he mentioned that just as we have never evolved to exercise, we've also not evolved to diet and lose weight. Therefore, for people who struggle to lose weight, it's not their fault and we shouldn't blame them. Now I completely agree with what Daniel is saying here and for me this is one of the big missing pieces when we try and tackle this issue. I believe that you can pretty much always help someone who is trying to lose weight achieve this in a sustainable and responsible way when you put compassion at the heart of your approach and when you help them identify the right approach for them. I've written about this in great detail in my upcoming book, Feel Great, Lose Weight, Long-Term Simple Habits for Lasting and Sustainable Weight Loss. It comes out in just

over two months and is now available to pre-order in the UK, USA, Canada, Australia, New Zealand, and India. Now, if you get value from my weekly podcasts, I have a favorite to ask from you. Why not take a moment right now to choose a few people who you think would really benefit from hearing this episode and send them a link with a personal note. This is a really impactful act of kindness that has benefits not just for the other person, but for you as well. So have a think about which people in your life would benefit from this conversation and send them a link to the episode as well as a personal message. And don't forget, each episode is also available on YouTube

if they prefer videos as opposed to audio podcasts. A big thank you to my wife, Vedanta Chastity, for producing this week's podcast and to Richard Hughes for audio engineering. Have a wonderful week. Make sure you have pressed subscribe

and I'll be back in one week's time with my latest conversation. Remember, you are the architects of your own health. Making lifestyle changes always worth it because when you feel better, you live more. I'll see you next time.