Something You Should Know - Individuality: Why You Are Different & What Exercise Really Does to Your Body and Mind

Episode Date: October 1, 2020

People generically call the dates on food packages, “expiration dates.” However, there are different kinds of expiration dates and they mean different things. This episode begins by sorting out what these different dates really mean. Don’t throw away any food until you hear this explanation. https://www.webmd.com/a-to-z-guides/features/do-food-expiration-dates-matter#1 There is no one like you and never will be. Why is that? What makes you so unique and different than everyone else? Still, you are a little like your parents and maybe a little your siblings while still being uniquely you. Ever wonder why? Find out when you listen to this fascinating discussion with David Linden, Professor of neuroscience at the Johns Hopkins University School of Medicine and author of the book Unique: The New Science of Human Individuality (https://amzn.to/2Sa7S3j) Making a good first impression is so important. There are 5 simple keys to making that good first impression and three ways you can really screw it up. Listen as I explain how to be truly memorable when you meet someone. Source: Mark Mazzarella, co-author of the book "Put Your Best Foot Forward" (https://amzn.to/3372kNz) You have heard all your life that exercise is good for you but do you know exactly how? And how much exercise is necessary to get the benefits? Listen to my conversation with Judy Foreman. She is a journalist who has won more than 50 journalism awards and she is author of 3 books including Exercise is Medicine: How Physical Activity Boosts Health and Slows (https://amzn.to/2Ge4VMI) Learn more about your ad choices. Visit megaphone.fm/adchoices

This episode is brought to you by Melissa and Doug. Wooden puzzles and building toys for problem solving and arts and crafts for creative thinking, Melissa and Doug makes toys that help kids take on the world. Because the way they play today shapes who they become tomorrow. Melissa and Doug. The play is pretend. The skills are real. Look for Melissa and Doug wherever you shop for toys. Today on Something You Should Know,

most expiration dates on food are not really expiration dates. I'll explain that. Then, you are an individual. You're different than everyone else. So what is it that makes you so unique? My answer is individuality is created by heredity, interacting with experience, filtered through the random nature of development.

Also, the keys to making a good first impression and the common ways people usually screw it up. And we've all heard that exercise is good for you. But how exactly? And what else does it do? The physical aspects are worthwhile too. I mean, if the science doesn't get you motivated, that exercise is good for you. But how exactly? And what else does it do? The physical aspects are worthwhile too. I mean, if the science doesn't get you motivated,

maybe vanity will. I mean, people who exercise tend to look better and act better. And literally, there's a difference between people's biological age and their chronological age. All this today on Something You Should Know. Metrolinks and Crosslinks are reminding everyone to be careful as Eglinton Crosstown LRT train testing is in progress.

Please be alert as trains can pass at any time on the tracks. Remember to follow all traffic signals, be careful along our tracks, and only make left turns where it's safe to do so. Be alert, be aware, and stay safe. Something you should know. Fascinating intel. The world's top experts. And practical advice you can use in your life.

Today, Something You Should Know with Mike Carruthers. Hi, welcome to Something You Should Know with Mike Carruthers. Hi, welcome to Something You Should Know. You know, one of the interesting and sometimes frustrating things about doing this podcast for the last four years is that every once in a while, we get these big spikes in audience. Normally, we can see our audience grow. It's very predictable, very organic. It gets a little bigger all the time. And we assume that's because people tell their friends and they tell their friends and it grows and grows and grows. And then every once in a while, there's this big boom, big jump in audience. And we don't really know why. We speculate it could be this or maybe somebody posted something on a blog, but we never really know where it comes from.

So if you're a new listener in the last few weeks, I would love to hear from you to find out how you found this podcast. You can write me at mike at somethingyoushouldknow.net, or there is a contact form on the somethingyoushouldknow.net website you can use. Either way, mike at somethingyoushouldknow.net, and let me know how you found this podcast. First up today, I know a lot of people who throw away milk and dairy products because of the expiration date that's on the container. And that's usually a mistake because there are different kinds of expiration dates. So let's take a look at what

those dates really mean. If it's a sell-by date, that basically tells the store how long they can display and sell the item. You should buy that product before that date for the best quality. But in most cases, it will be edible for some time after that. Milk is an example. The date on a milk carton is not an expiration date, it's a sell-by date, which usually means the milk will be good for quite a while after that. If it says best if used by, that refers to quality, not safety. That window of time will give you the best flavor or quality. Sour cream, for example, is already sour, but it has a better taste within the recommended dates. Use by date.

This is the last date recommended to use the product, and it's determined by the manufacturer. So again, it's more about quality than safety. And then there's the expiration date, and this is the one to watch out for. If a food product has the actual term expiration date on it, it's referring to the last date the food should be eaten or used. If you have to count how many days ago that was, you better toss it out. And that is something you should know.

You are an individual. And even if you have an identical twin, you still are, in many ways, quite different from your twin. And you're different from your parents. And you're different from your parents. And you're different from everyone else. You are an individual. So what makes us different?

What makes you, you? Seems like you'd want to know that. I know I certainly want to know that. And here to tell us is David Linden. David is a professor of neuroscience at the Johns Hopkins University School of Medicine, and he's author of the book, Unique, The New Science of Human Individuality. Hi, David. Thanks for having me on.

So, how did you get involved in exploring and researching human individuality? Well, I came about it in an unusual way, and that was through online dating. So, I'm a biologist, and about five years ago, I found myself single, and I went on OkCupid, which is one of the online dating sites, and I was struck with, you know, a catalog of human traits. Everything from, I tend to wake up late, to I I have a Boston accent to I hate white chocolate, but like IPA beers. And so, of course, the nerdy wheels in my mind started to turn and think, well, you know, what do we know about how these traits come to be? What do we know about how human individuality is formed?

And so how is it formed? Because I've always thought of individuality as something that is always changing in a person. I'm not the same person I was 10 years ago, neither is anybody else, because I think we are the sum of our experiences and our genetics and all that. So what's your answer? How is human individuality formed? Most people, if asked this question, might come back with the famous phrase, nature versus nurture, meaning that you're formed by a combination of the genes that you inherited from your parents and how your parents, family, and community raised you,

nurture. And I hate that expression, first of all, because I think nurture is too confining. The non-heritable part of individuality is much broader than how your parents raised you. It's much broader than all social experience in your life. It includes things like what foods your mother ate when she was carrying you in utero, and what diseases you fought off early in your life, and the day length and the changes in the day length in the place when you were a child. All of these things contribute to our individuality. The other part that I hate is versus, because it's not in competition. So, heredity interacts with experience, which is the broader word I would use in place of nurture. For example, if you're born fortunate

enough to be quick and coordinated, then you're much more likely to play sports and practice sports and get better and better at it. And so that's a way in which heredity and experience are not in opposition. It's not versus. They are interacting. In this case, they're supporting each other. Or if you inherit the gene for a metabolic disease called phenylketonuria or PKU, you only get the disease if you also eat foods that are rich in phenylalanine in your diet. So again, this isn't a versus. This is a more complicated form of interaction. And then the final part, that complication to this is sheer randomness of development. So, if you look at genetically identical twins at the moment they're born, they're not really identical either in their

bodies or in their temperaments. They're always a bit different. And if you put them in a medical scanning machine, you would find that the sizes and the shapes of their organs are different. And if you put them in a medical scanning machine, you would find that the sizes and the shapes of their organs are different. Why? It's because your genes don't give a precise blueprint wiring diagram of all the cells and what they do and what they connect to in your body. Rather, they give a set of very general instructions, which are then kind of randomly played out to create you as an individual. So my answer is individuality is created by heredity interacting with experience filtered through the random nature of development. Isn't another way of saying this, or at least part of what you're saying, is that

people are different. You know, it's just some people like chocolate, some people don't, and that's the beginning and the end of it. Or is that too simplistic? You can say that if that's the only level you care about. But if you're curious and you want to know how people become different, then you can dig in a little bit and you can say, hmm, let's look at different traits. Well, so here's a human trait, speech accent. I'm not talking about whether your speech is, you have a low voice or a high voice or a reedy voice or resonant voice, but the kind of local accent that you pick up from the people you grew up with, that is a trait that is entirely dependent on experience. It has nothing to do with your genes whatsoever.

Another trait is earwax type. Now, this may sound really trivial, and it kind of is, but everybody's got either wet or dry earwax. And wet or dry earwax is determined by variation in a single gene, and it has nothing to do with how your parents raised you or where you grew up or what foods you eat or anything else. It is entirely dependent on that gene. So at the opposite end of the spectrum from speech accent, earwax type is 100% heritable. But most traits, whether they are physical traits like height or behavioral traits like shyness or novelty seeking, land somewhere in the middle, in the 30 to 80% heritable range. And some of those traits that make us an individual, you can change if you really want to. I mean, I know people, to use your example, I know people who have regional accents

and they've had them since they were a child. They haven't lived in that region for a long time, but they still have the accent, whereas other people have an accent, leave the area, and they lose the accent pretty quickly. That's right. So you can modify things as a result of experience. So in the case of speech accent, it's all experiential. For some

people, it's locked in early in life. And for other people, it kind of naturally drifts if they move to a different community. And for other people, they move to a different community and they may decide to sort of keep it particularly as a badge of their own origins. So we are built to be plastic in many ways, not in every trait, not in earwax, but most traits have at least some experiential component. Now, in some cases, the experience happens early in life, and so there's nothing you can do about it by the time you grow up. Here's an example. So, people who grow up, have their first two years of life in warm climates near the tropics, they have many more of their sweat glands innervated, receiving signals from the brain, meaning that they can sweat when their core temperature goes up, which is adaptive when you live in a really hot place. Whereas people who live near the poles don't have nearly as many of these,

and that was set in their early life. So if you grow up near the poles, and then you move to the tropics, you are stuck with polar sweat glands, and you're likely to be very susceptible to heat stroke. As a result, there's no experience you can do as an adult to then change that. It was experience-driven, but there's a critical period for that experience early in your life. Are there things, from your observation, are there things about our individuality that people generally think you can change that really don't change very much and then vice versa? One way that you can change your various traits is by changing your diet. So you are affected by the properties of microbiota in your gut and your gut bacteria are influenced by what you eat.

So certainly that's a way that you can change things and you can change your gut, and your gut bacteria are influenced by what you eat. So, certainly, that's a way that you can change things, and you can change your metabolism and the way you absorb nutrients from your gut with your diet. To go to something more behavioral, the things that we can change are things like political ideas, moral ideas, religious ideas, training for new jobs. Those are things that are easily changeable. Once you're an adult, your personality type, things like neuroticism, openness, conscientiousness, agreeableness, these are the standard terms that psychologists use that they abbreviate to form the word ocean. Your so-called ocean personality traits are more locked in from, you know, age 20 on. We're talking about individuality, what makes you, you. And my

guest is David Linden. He is a professor of neuroscience at Johns Hopkins University, and his book is Unique, the New Science of Human Individuality. how to find happiness and peace of mind. Thank you, and have a nice life. Unfortunately, life doesn't come with an owner's manual. That's why there's BetterHelp Online Therapy. Connect with a credentialed therapist by phone, video, or online chat. Visit betterhelp.com to learn more. That's betterhelp.com. Bumble knows it's hard to start conversations.

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With opening moves, you simply choose a question to be automatically sent to your matches. Then sit back and let your matches start the chat. Download Bumble and try it for yourself. So David, what about things like artistic ability, your ability to draw? Like I've never been able to draw, but I've always believed I've never been able to draw. So I've never really tried it very hard, but tried very hard. But, you know, my son is a very good artist and he believes he's a good artist, but could I be as good an artist as someone else if I, or is artistic ability something that is just in me or not in me? Well, it's something that you have to, if you're only coming to it in adults,

it's going to be harder to develop it. But it's certainly something that everyone can get better at, right? There's a whole lot of skills, you know, playing tennis, writing, drawing. Everybody can practice and get better. But it doesn't mean that everyone is going to be Degas or Andre Agassi, for example. You know, we are limited by certain intrinsic things. Sports is a great example of this. If you look at professional baseball players, they all have extraordinarily good visual acuity. You can't be a professional baseball player unless you have something on the order of 2015 vision, which occurs in something like one in 300,000 people.

So yeah, sure, you can get better at baseball playing with your friends and join a league and practice and get your skills better. But you can't just decide out of sheer force of will that you're going to play well enough to be in Major League Baseball just because you decide it, because you probably will have physical limitations that will keep you from doing that. And what is that limitation? What is that vision thing? Well, it's the acuity of your vision. So you know how vision, you know, they say perfect vision is 20-20. Well, better than perfect vision is 20-15 or 20-10.

Worse than perfect vision is 20-30 or 20-40. So professional baseball players almost all have extraordinary visual acuity, and they didn't develop it through practice. They're born with it. What about things like temperament? Some people are grouchier. Other people are more optimistic. Some people are loners. Some people thrive in the company of others.

Those kind of things. kind of those kind of things and often often those different people come from the same family so you wonder well how come johnny is very social and his sister suzy is more of a loner and what about that right i would say just to be even clearer about it look at a pair of identical twins as adults, and they don't have identical personalities. Their personalities are going to be, on average, much more similar than a pair of fraternal siblings that share 50% of their genes as opposed to 100% for identical twins. But there is still a lot left over from experience and randomness to contribute. So, you know, aside from a few ways like earwax type, we're not slaves to what we inherit from our parents. a lot of ideas about how personality and lifestyle types develop that turn out not to hold up to scrutiny. For example, many people believe that firstborn children tend to go out in the world

and become leaders, and middleborn children are the peacemakers, and the younger children are clever and learn to get around the rules. And all of these stereotypes are true, but only for interactions within the family. Once kids get outside the family, and certainly by the time they get to adulthood, none of these stereotypes holds up. There's not an inordinate number of first-born entrepreneurial CEOs, for example. Let's talk about preferences like tastes. Some people like broccoli, some people don't. I love peaches and I've been trying to get my son to eat peaches and he says he doesn't like them. I don't know that he's ever really eaten them. And it may be that he doesn't like them because he decided he didn't like them

even before he tasted them. But when people say they don't like something or they do like something, it would seem that that's a result of experience. Well, it is heavily experience in the sense, I like to say that humans are the anti-pandas, in the sense that pandas live in one little place in southern China, and they eat one thing, bamboo, that is it, and one particular type of bamboo, and so they're kind of stuck. Humans have been able to spread all over the planet by being able to eat different foods in different localities, everywhere from the Arctic to the tropics and back again. We have

survived by being food generalists. So we are born with some inborn likes and dislikes. We're born to like sweet things and to dislike bitter things. But again, those things really only hold in childhood. Plenty of people like bitter stuff as they grow up. And when it comes to odors, there are almost no odors that we're born disliking. And any parent will tell you, for example, that babies are not born disliking the smell of poop. They don't know that it's disgusting. You have to teach them that. They will happily play with it. So, you know, even something as foul as that, you think, oh boy, we would have an inborn aversion to that. No, we don't. And the reason we don't is to keep our options open as far as food

is concerned. Well, and food's a good example of, I think, of if you talk to, if you had someone who's never eaten chocolate, eat it, they're probably not going to go, oh, this is the greatest thing in the world because they've never tasted it before they so it's it it's almost as if new things are difficult well sometimes they are and sometimes they aren't and we can look at food history a good example is things that were introduced to europe from other places so when the tomato which was native to the Americans, came to Europe, at first people were very, very suspicious of it. And it was a long, long time before it really made its way into foods. However, the chili pepper, when it was introduced into Asia

from the Americas, was instantly seized upon. And it's kind of a remarkable thing to think about. Before there was trade with the Americas, Thai food wasn't spicy. Indian food wasn't spicy. They didn't have chili pepper because it wasn't a natural product. But those cultures jumped all over it as soon as they had access to it., what determines whether something is immediately adopted or adopted slowly is complicated and cultural. In the case of tomatoes, you know, tomatoes are in the nightshade family and people were worried that they would be poisonous, even though they're not. Well, it's interesting that we do change over time. As individuals, we're not the same as we were 10 years ago. Time does change people,

but when we try to make deliberate changes to our traits, it's hard, like losing weight or stopping smoking or having more friends, things like that. Things we want to change are hard to change. Well, that's certainly true. I mean, body mass index, which is a pretty good measure for carrying weight, is on the order of 70% heritable in the United States. So, you know, that means that, well, yeah, there are things you can do, but what you

have to work with is that 30%, not the whole 100%. Compare people in the United States with people in France. Now, on average, people in the United States have statistically a higher body mass index than people in France. And among people in the United States, body mass index is highly heritable. If you look at people in France, body mass index is highly heritable there also. But some people then would go on and say, well, because of that, that must mean that the French and the Americans are genetically different, and that's the reason for their difference in average body mass. But that's not true at all.

The reason that Americans are on average have higher body mass index than the French is because we eat more and exercise less. And so it seems as if we're the result, each one of us is the result of our own recipe. That, you know, there's so many different influences that make up who we are as an individual, and those differences are never the same in two people, and that's what makes us an individual. Yeah, I would say a recipe is a really good analogy, and there's a geneticist in Ireland named Kevin Mitchell, and he has a great phrase, which is, even if you're using the same recipe, you can't bake exactly the same cake twice. And by that, he means that, you know, there's going to be subtle variations in the process. You're not going to stir it the exact same way. You're not going to add the ingredients in the exact same order. And that's how developmental randomness happens.

Which is exactly what makes us individuals, or at least part of it. David Linden has been my guest. He is a professor of neuroscience at Johns Hopkins University School of Medicine, and his book is called Unique, the New Science of Human Individuality. And there's a link to that book at Amazon in the show notes. Thanks for coming on, David. Thanks, Mike, for having me on. It was lots of fun. This winter, take a trip to Tampa on Porter Airlines. Enjoy the warm Tampa Bay temperatures and warm Porter hospitality on your way there. All Porter fares include beer, wine, and snacks, and free fast-streaming Wi-Fi on planes with no middle seats.

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The Jordan Harbinger Show on Apple Podcasts, Spotify, or wherever you get your podcasts. I bet you've heard more than once in your life that it's important to exercise because exercise is good for you. But how is it good for you? But how is it good for you? And what is it good for specifically? Aren't different kinds of exercise good for different things? And of course, if exercise is good for you, how much exercise do you have to do to get all that goodness?

Well, here to answer those questions and many more is Judy Foreman. Judy is a journalist who has won more than 50 journalism awards, and she is the author of three books, her latest being Exercise is Medicine, How Physical Activity Boosts Health and Slows Aging. Hi, Judy. Hi, hi. Thank you for having me. So it's interesting that if you ask people if exercise is good for you, pretty much everyone agrees, but ask them exactly how it's good for you, and the answers are kind of vague, like, well, it's good for your heart, or it builds muscles, and that's a good thing. Yeah, it's kind of like hearing that vegetables are good for you, but

you know exactly why. Well, that was exactly the question that I started out with, and I've been a science writer all my professional life as well as an exerciser, and I finally put those two things together, and that was the fun part of this research for this book, actually, was realizing why and how exercise is so good for you, like molecule by molecule, organ by organ. And it was astounding. I mean, like you, I already knew exercise was good, but I didn't know why it was so good. And it was fascinating finding out. And so in a nutshell, why is it good for you?

Because it affects hundreds, literally hundreds and hundreds of molecules in the body. We evolved to exercise. We did not evolve to sit in front of our computers all day, even though that's what a lot of us, including me, tend to do. It really works to reduce inflammation, chronic inflammation, which is the underlying cause of a lot of diseases, especially of aging, heart disease, atherosclerosis, a lot of brain malfunction. It helps ward off Alzheimer's. It's very good for cognitive maintenance of your cognitive facilities. It's terrific as both a preventer and a treatment for depression.

It has its biggest longevity effects on the heart because it affects so many different things, blood pressure, how flexible your blood vessels are, how much your heart can pump with each beat, all those things. I mean, organ by organ and system by system, it's really amazing. And I hope at some point we get to talk about the brain benefits of exercise, because I think those are less well-known to people. So when you say that, you know, it's good for you organ by organ and all that, it's hard, I think, to imagine, like, if I exercise, how that's going to help my pancreas or my liver or my spleen. What's the connection?

Basically, it gets into a lot of basic molecular biology. For instance, exercise has a huge effect on mitochondria, which are in every cell. Those are the powerhouses, so-called, inside every cell. That's where in the cell your body takes in oxygen from the air and food from what you eat and turns it into an energy molecule called ATP, which is adenosine triphosphate. I mean, people don't have to remember that, but you might want to remember ATP. And that's in all our cells, so that affects all of our organs. And when you exercise, the contractions of the muscle cause a gene called

PGC1-alpha. And again, people don't have to remember that, but that the contraction of the muscle triggers, turns on a gene that in turn makes the body produce more mitochondria. So you're literally building up your body's ability to produce and ultimately to use energy every time you contract a muscle. And interestingly, it's only in the muscles that really, that contract, that build up the mitochondria. So there've been experiments with several processes of exercise, where if you do it with one leg, like ride a bike, a stationary bike with one leg and not the other leg, the leg that has been exercised has many more molecular changes, including more mitochondria, than the leg that doesn't

get the exercise. So it's really, scientists now know this at a very basic, tiny level, and it's quite astounding. It's so interesting, because I think when people think about the benefits of exercise, they think they're physical, that you see them, you're thinner than that guy, or you have bigger muscles than that other guy. And that that is the benefit, or that your lung capacity is better because you do cardio so you can, you know, run farther and you have... But it kind of stops there. I think that's the perception a lot of people have is that that's the beginning and the end of the benefits.

And what you're saying is it's so much more than that. That's right. And the visible aspects are worthwhile, too. I mean, if the science doesn't get you motivated, maybe vanity will. I mean, people who exercise tend to look better and act better. Literally, there's a difference between people's biological age and their chronological age. Often, you can see that. You go to a high school reunion or a college reunion, and chances are you'll be able to spot the people who do a lot of exercise,

and sadly, the ones who don't. And so that always brings up the question, how much exercise to get these benefits? Well, the basic sort of minimum, and it is a minimum, is what the government recommends. And, you know, unlike what the government has done with the coronavirus, they actually consulted and took the advice of experts for the exercise guidelines. And the minimum is considered 150, 150 minutes a week of moderate intensity exercise. That's enough to get a lot of the health benefits. It won't be enough to train for a marathon or do bodybuilding or some really serious competitive sport, but that's a good minimum for basic fitness.

And that 150 minutes a week translates into just 30 minutes a day. And that's moderate intensity exercise. And there are technical definitions for moderate exercise, but the one that people can remember is it's moderate if you can talk, but it's intense if you can't sing. So as long as you can talk and even sing a little bit, it's moderate. If you want intense, you'll be panting so hard you won't be able to sing. So basically moving along pretty fast, you know, like for a mile, somewhere between 15 minutes is a brisk walk, 20 minutes is sort of a normal walk for a mile. And walking counts.

And you don't even have to get the 30 minutes all in a row. You can do 10 minutes in the morning to the subway, 10 minutes at night, and another 10 minutes, I don't know, grocery shopping or something. You can add it all together. The key is just not to spend the day sitting down. One of the arguments that I've heard, well, the argument is this, anything is better than nothing. That's true. Just getting off the couch is important. In fact, one of my favorite studies is by an exercise guy named Steve Blair, who did one study I'm thinking of was, I think, in 1980, and he used 10,000 men and 3,000 women and actually put them on treadmills.

So you're kind of walking on this moving belt in the gym, which is a more precise way of measuring exercise than asking people to remember how much they do. And the most fit people had much better cardiovascular functioning than the least fit. But the important take-home message was just doing enough to get out of the least fit category was a huge benefit to people. So, you know, just getting off the couch helps. Standing up every half an hour or hour if you're sitting at your computer or watching TV, that helps. But to your point, anything is better than nothing, but the bare minimum is a whole lot better than even less. So talk about this whole notion that sitting kills and sitting is the new smoking. I mean, it sounds a little over the top to me. People have been sitting since there have

been people. And, you know, I don't think that anyone's ever seen on a death certificate, you know, cause of death, sitting too much. There are a lot of metabolic reasons why sitting for long periods of time. Obviously, you have to sit sometimes. Even our caveman ancestors sat around the fire and had dinner. But they also ran all day or walked all day or gardened or hunted and gathered. There are a number of reasons why sitting is so bad, but one of the most obvious is that you tend to gain weight. And you tend to gain weight around your stomach. Your belly fat gets fat. And that fat, you know, we sort of think

of it as just kind of unattractive blob of tissue. But in fact, this visceral fat is a very active metabolic organ. It pumps out chemicals called pro-inflammatory cytokines. These are just little chemicals that the fat produces. It's a very active organ. And these create chronic inflammation all over the body. This is different from the inflammation that you get if you cut your finger and it swells up. You see that it's visible and it goes away in a few days after the wound heals. But with chronic inflammation that's caused by these inflammatory molecules being pumped out by fat, that affects, as I mentioned before, the health or lack of health of your blood vessels, your heart.

Diabetes is caused a lot by underlying inflammation. It's basically really bad for you. And exercise is the way to reverse that. So that's why sitting is so bad. And one of the more depressing studies I read was a 2012 study of about a quarter of a million adults, American adults. And it found that even if you exercise seven hours a week, which is basically an hour a day, which I, as an exercise fanatic, do, if you spend seven hours a day sitting still watching TV, you're still at risk from the downside of sitting. So, you know, definitely do your hour a day if you can, which is more than the minimum.

But even so, you can't just spend your whole day sitting. So one of the things that concerns people have, okay, you've just self-identified as an exercise fanatic. I shouldn't have said fanatic. Let's say I do the minimum. A lot of people hate it. They just, the thought of getting up and going to a gym or going to a, doing exercise for the sake of exercise is just, I mean, they'd rather have a root canal. And those people are hard, I mean, and then there's the argument is, of course, well, you don't have to really exercise. You can just walk. But they don't have to really exercise. You can just walk. But they don't want to do that.

I mean, there's something about exercise, the concept of exercise, that just turns people off. It does. And actually, it's funny that you mention that because I'm actually chairing a panel for an online conference. And one of my colleagues on the panel is Dr. Daniel Lieberman, who's the Harvard evolutionary biologist. And we've been planning the panel together, and he's been pointing out both exercise and diet are kind of weird concepts evolutionarily. When we were hunter-gatherer people, we didn't have to diet. The problem was starvation, not excess. And we didn't have to exercise because it was built into our lives.

So we are evolutionary. We're sort of at odds with ourselves from an evolutionary point of view because we have changed the world around us so that we get no exercise unless we go out of our way to do it. You know, in the olden days when people, before so many, quote-unquote, labor-saving machines, people got a lot of work, a lot of exercise just doing their work, and they didn't call it exercise. It was just, you know, hoeing the field or being on your feet all day, cooking for 10 kids and doing the laundry. I mean, we sort of invented the idea of exercise out of biological necessity, but

it's new evolutionarily, and I know a lot of people do hate it. And one of the things I've been struggling with is, you know, so how do you, since we do need to do it, how do you get people to do it? And I talked with a friend of mine who does not exercise at all, hates it, just like you said. And I said, you know, she's kind of fat. Would you do it for vanity? No, no, she hates the way she looks, but she wouldn't do it. Would you do it because it's good for you? No, I don't really care.

Would you do it if there were a social aspect? If you had to meet a friend at 9 o'clock three times a week in the morning, would you do it? Yes. The social aspect can be very powerful in getting people to make a commitment to somebody else so that you're not just letting yourself down, you'd be letting a friend down if you don't do it. That seems to help people be motivated to do it, the social thing. Yeah, well, you know, it's interesting about that, because I agree with you. It seems as if the social aspect of it and the accountability of meeting somebody to exercise

would be really powerful. Yet, I go to a gym pretty regularly, and when I'm in there, because I've noticed this, the people in there are all alone. They're not with somebody. Unless they're in a class. No, yeah, I just mean the people around the weights and the treadmills and all that. They don't come in with a friend.

They come in alone. Yeah, and they want to sort of get it done and get out of there and get on to the next thing. No, I totally agree. I mean, I think classes are different in that respect, but you're completely right. I mean, people get these fancy gym outfits and nobody's really paying attention. Well, that's the other thing, too, is that a lot of people are so intimidated by going to a gym because they think everybody's staring at them, and nobody's staring at them. Nobody cares.

I know. I think that's right. I think that's right. You said you wanted to talk about it, so let's talk about exercise in the brain. Oh, yes. Thank you for remembering that. So there's a molecule that most people have not heard of, but it's a really important molecule, and it's called BDNF, which stands for brain derived neurotrophic factor, which just means brain derived means it's made in the brain. This little molecule is made in the brain.

Neurotrophic means it goes to nerve cells and factor means factor. The better way to remember it is the nickname that a scientist I know gave it, which is miracle grow, miracle grow for the brain. And in my talk that I give now online but previously to live audiences, I picture a watering can with, instead of water drops coming out, miracle drops going onto the brain. What happens in the brain is that when you exercise, the cells in your brain put out this miracle grow. And it goes particularly to part of the brain called the hippocampus, H-I-P-P-O, campus. And this is the major memory center for the brain. And it's also an important emotional center. And it literally makes new brain cells grow. The hippocampus gets bigger.

And this has two big effects. One, a huge effect on cognition. There are so many studies showing that exercisers have better cognition. They do better on tests. They have better memories, all that stuff. And it's also cognitively important because it can help prevent Alzheimer's. There was a major study from Ontario a few years ago that showed that if every person who is right now inactive became active, we could prevent one in every seven cases of

Alzheimer's. That's a huge multiplier effect. That really shows you the power of keeping this miracle grow going. The other important thing this chemical does is it helps prevent and also treat depression. There are so many studies on this. It's amazing. It helps prevent depression. And if you already have depression, in many cases, exercise can work as well as some of the common drugs like Prozac. Again, it's because of this chemical BDNF, which interestingly seems to work in tandem with serotonin.

And serotonin is the neurotransmitter that some of the antidepressant drugs increase levels of in the brain. So if you're not doing it for any other reason, do exercise to protect your brain. Your brain will thank you in many ways and over many years. One of the reasons people start exercising who haven't exercised for a long time is they want to lose weight. And the research has proven time and time again that exercise is a lousy way to lose weight. Right. And yet, it's baked in. I mean, you go to any trainer, anybody that talks about fitness,

they will tell you that exercise will help you lose weight, and it really doesn't. No, and it's basically plain old arithmetic. I just swam an hour in a pool. I'm on a master swimming team, and I probably burned, let's say optimistically, 400 calories. If I come home and eat the chocolate chip cookie that's been looking at me, there goes that 400 calories. I mean, home and eat the chocolate chip cookie that's been looking at me,

there goes that 400 calories. I mean, the math just doesn't work. It takes so long and so much effort to burn calories by exercise that you can wipe out that whole benefit with one, you know, ice cream cone or one cookie or, you know, a sandwich with big pieces of bread. I mean, that's really the depressing part. However, you know, it can with big pieces of bread. I mean, that's really the depressing part. However, you know, it can sort of be an ad. I mean, it's good to exercise, obviously, but my basic kind of rule of thumb is exercise for fitness and diet for weight control because you can lose weight with exercise if you do an awful lot of it

so that you're burning more calories. It's basically calories in, calories out. And if you're putting out more calories in exercise than you're taking in in food, yeah, then you'll lose weight. But most of us find that incredibly hard to do because, you know, you can wipe out the gains with just such a little sinful behavior like one cookie. What we haven't really talked about, so let's talk about it, is the relationship between exercise and aging. Well, there was a big study in 2013 by a bunch of European researchers, and they identified nine so-called hallmarks of aging, and they are very, very basic, and the words are kind of complicated but

there are things like um genomic instability and um mitochondrial growth and telomere maintenance all these really basic cellular processes are influenced in a good direction by exercise um you know that's not what most of us think when we're on an exercise bike. We're not thinking about our mitochondria or our telomeres or something, but it's been shown that these are the basic hallmarks of aging, and exercise has a good influence on all of them. So a lot of reason to do it, to find the motivation if you don't have it to exercise. And yet there are people like you who enjoy it, and I don't know why some people do and some people don't,

but maybe it's just the way you've trained yourself. Well, and then there's one little final tidbit, which is people think that they feel better after they exercise because of endorphins, but that's not actually why people feel good after exercise. It's actually endocannabinoids, which are basically molecules. They're marijuana, essentially. It's their own type of marijuana that we make in the body. And exercise definitely increases these levels. So the runner's high is a real thing, and it can be the swimmer's high or

the basketball player's high. I mean, if you do enough exercise, you do actually feel good. So that's another motivation. But of course, people who aren't exercising don't get that experience, so they never quite believe it. Well, clearly there are a lot of good reasons to exercise if you can find the motivation to do it. And it's interesting to hear exactly why it is so good for you. Judy Foreman has been my guest. She is a journalist, and her book is called Exercise is Medicine, How Physical Activity Boosts Health and Slows Aging. And you will find a link to that book at Amazon in the show notes for this episode.

Thank you, Judy. Great. Well, thank you so much. I enjoyed it. I'm sure you know that people judge you instantly, just as you judge other people instantly. That first impression is so important. And according to some fascinating research, there are five elements to a good first impression. Eye contact, smile, firm handshake, good posture, and enthusiasm.

People who exhibit these traits are rated higher for trustworthiness, caring, humility, and capability. However, there are three things that will kill a good first impression, even if you do all those things right. And those three things are rudeness or bad manners, aggressive behavior, or bad personal hygiene. And that is something you should know. And a reminder, I mentioned it at the very beginning of this episode of the podcast. If you're a new listener, drop me a line. Tell me how you found this podcast.

You can write to me at Mike at somethingyoushouldknow.net. I'm Mike Carruthers. Thanks for listening today to Something You Should Know. Hello, I'm Simon Jack. And I'm Zing Zing. And together we host Good Bad Billionaire, the podcast exploring the minds, the motives, and the money of some of the world's richest individuals.

Every episode, we pick a billionaire and we find out how they made their money. And then we judge them. Are they good, bad or just another billionaire? Good Bad Billionaire from the BBC World Service. Listen now, wherever you get your BBC podcasts. To be continued... the blasphemous truth that ours is not a loving God and we are not its favored children. The Heresies of Randolph Bantwine wherever podcasts are available.