If we condense the history of humanity to a period of twenty-four hours, we can see that we were hunter-gatherers until 11:40 p.m. We didn’t become industrialized until 11:59:40 pm, twenty seconds before midnight. We entered the digital age (i.e., we connected to the Internet) at 11:59:59—that is, one second before midnight!
Why are we lazy if it’s so beneficial to be active?
There is absolutely no doubt that our bodies and brains have evolved to handle activity levels far greater than we engage in today. The paradox is that we’ve also become lazy. If it’s so good for us all-around to go outside for a walk or a run, why is it so nice to just lounge on the couch and snack on potato chips? That’s because throughout most of human history, we’ve had to deal with an energy and calorie deficit—not an excess, like we have today. Calorie-dense meals were rare for our hunting ancestors, and it was always better to eat the food right away lest someone else tried to steal it. That’s why calorie-rich foods taste so good—your brain wants you to eat all of it to fill your energy stores.
If our ancestors on the savanna came upon a tree full of sweet, calorific fruits, it wasn’t particularly smart to pick one and save the rest for later, as we’ve been taught to do when offered a piece of chocolate from a box. For them, a better strategy was to eat it all immediately to not miss out on all those precious calories. If they waited until the next day, the fruits would probably all be gone; someone else would have taken them. That urge is still with us. For example, when faced with that box of chocolates, your brain says, “Scarf down the entire box right now, eat every little bit. Otherwise someone else will snag them! We might need the calories tomorrow if there’s no food.” That’s why we feel compelled to eat the entire contents of the box.
We’re walking out of step with our biological age—or, should I say, we’re sitting out of step.
The body’s energy reserves don’t depend only on how much you fill them, but also on how much energy you expend. Not using up energy unnecessarily, and being able to keep a little around the middle in reserve in case of famine, has been a survival trump card for us humans. This is an inner urge to economize our efforts and to conserve energy that can help tide us over when times are hard. So when you’re lounging on the couch in front of the television, dreaming up excuses to cancel that run on the trail or the walk, it is, paradoxically, your hunter-gatherer brain that is telling you to stay put. “Sit and save energy” is the reasoning. “It’ll come in handy the day there’s no food, and you’ll need energy.”
It’s obvious that this inherent urge to save calories has consequences for our weight. If you’re not convinced, look at what happens in places once considered third-world countries that have experienced rapid economic growth, and that have in a few short decades given themselves over to a lifestyle full of fast food, ever-present sugar, and couch-potato TV watching. Rates of obesity have skyrocketed in these countries. It is well known that this new lifestyle causes us to gain weight, but we are not as familiar with the consequences it has on our brain.
FULL SPEED BACKWARDS!
The huge technological advancement over the last decades has given us commodities such as the Internet, smartphones, and food that can be ordered from home with the click of a mouse. Meanwhile, we’re moving further and further away from the life we have evolved for. Our increased comfort makes us restless, anxious, and unhappy. Again, why do our mental functions suffer when we’re sedentary?
Here too, the answer can be found in the past. Basically, our brain looks the same as our ancestors’ ten thousand years ago. They didn’t compete in marathons or work out to get in shape before swimsuit season. They were physically active simply to survive: they ran or walked in search of food, to get away from danger, and to find new places to live.
The brain is programmed to give us a kick of dopamine so we feel better if we move our body, since hunting increases our chances of survival. Moreover, those chances of survival increase if we run away from danger or discover a new area to settle down in. Since the brain hasn’t changed very much over those ten thousand years, the same applies to us today. When we engage in behaviors that increased our ancestors’ chances of survival, our brain rewards us with a feeling of pleasure to encourage us to repeat those behaviors.
When you come home after your run or walk, your brain interprets the activity as if you’d been out looking for food or a better place to live, for which you’ll be rewarded with a feeling of well-being. You are not feeling a shot of dopamine, serotonin, and endorphins because you’ve read in a health magazine that it’s good for you to exercise; you are getting the reward because your brain thinks you’ve increased your chances of survival. That’s also how we’re able to understand why we are “punished” by feelings of lousiness when we’re sedentary. You don’t catch any prey by remaining seated all day, and it doesn’t lead you to find a new dwelling place, either. Being sedentary has never been good for our survival, which is why it makes many of us feel sick to this day.
In this light, it’s also easy to understand why physical activity strengthens other cerebral functions. When our ancestors hunted for food, it was important that they stay focused. If you sneak up on an animal on the savanna, you need to concentrate and react to the smallest movement to boost your odds of making the kill. That’s probably why you and I become more focused when we move our bodies.
Exercise also improves our memory, but how does that work? It’s probably because movement has meant that we’ve seen new places and new environments, and it’s important to be especially vigilant when we experience new things. Being sedentary and staying rooted in one spot makes the brain think that we haven’t experienced or seen anything new, so there’s no need to improve memory. Our brain has not evolved for us to experience new things through a cell phone or a computer; our brain does not consider sitting and staring at a screen a new experience.
The brain is still on the savanna
Your brain doesn’t care that the world no longer looks like what it has evolved for. It’s still very much on the savanna, and it will work a bit better if you treat it as if it were. Our exercising less is, of course, not the only change in our lifestyle and environment that affects our brain’s performance and how we feel. Environmental toxins, urbanization, modern diet, and living in completely different social structures also play a role. Still, the lack of physical activity is one of the most important changes, with regards to both our physical and mental health. Our decreasing level of exercise is a problem that can be solved quite simply. While we may not be able to ditch our lives in the city and move into the woods to hunt, we can move our bodies a little more. We can take a step back to a life our brain has evolved for by becoming more active, for which our brains will offer us ample rewards.
Many of us feel that something is amiss even though we live in unprecedented material comfort. But it’s not too strange that we feel this way, because our modern society has removed us far from the life we were built for. The lifestyle changes we have experienced over just a few generations have brought about incredible advantages—keep in mind how much our life span has increased. On the other hand, we tend to become depressed, anxious, stressed out, and unfocused for the simple reason that our brain has not evolved to deal with our current way of life.
You can relieve a great deal of this malaise by engaging in more physical activity. Of course, this doesn’t mean that all mental problems can be solved by running on a trail or that regular tennis matches can replace all psychotropic medication. What it does mean is that most of us stand to gain a lot by exercising a little more to feel healthier and to function better mentally. If we feel low or are stressed out, maybe we should ask ourselves if there’s anything in our way of life that could be altered and not automatically assume that all problems can be cured by taking a pill.
“Walking is man’s best medicine”
If I were reading this book, I would be thinking by now that if exercise was truly that good for the brain, the
n surely everyone would be aware of it, right? It should be as widely known as the fact that smoking is bad for you and that coffee makes you perk up. I believe we’ve always known how good physical activity is for the brain, but over the past 150 years we’ve forgotten all about it. Walking is man’s best medicine. These words are not a cliché from a health magazine; rather, they come from the mouth of Hippocrates, the father of medicine, who as far back as 2,500 years ago and without the benefit of modern medical technology understood how important moving our body was for our physical and mental health.
During the past 150 years, we’ve experienced staggering medical advances that have given us everything from vaccines to antibiotics, MRI scans to molecular-targeting cancer drugs. In the wake of all these amazing discoveries, everything that was obvious to us earlier seems to have fallen by the wayside. We’ve forgotten that the body’s and the brain’s most important medicine might be bodily movement. Hopefully this will change. Lately, research has caught up with Hippocrates and confirms his historic, yet wise, words. We haven’t quite grasped just how important movement is and which mechanisms are responsible for turning a run into a mental upgrade. It’s as if history were getting back at us ironically, since it is one of our most advanced medical technologies, the MRI, that has made us revisit the worth of our least sophisticated medicine—physical activity.
It’s not about being a jock
Due to our current mega health hype, and because every other magazine on newsstands is a fitness magazine, tickets to events like the New York Marathon and the Swedish Vasa Cross-Country Ski Competition sell out within hours. At the same time, many people feel that they don’t want or can’t take part in this exercise hysteria, and I understand completely! To those, I want to say: forget about long-distance running, fitness magazines, and health hysteria, but make sure you do some type of exercise.
Being physically active isn’t about being a jock or having six-pack abs; it’s about providing the brain with the most advantageous conditions so it can perform at its best. Brain exercise apps have become a multibillion industry. Forget about them—they don’t work. And take no notice of nutritional supplements and other “miracle methods” that are supposed to work wonders for the brain; they’re ineffective, as well. Instead, spend time on what science has so clearly shown works to strengthen your brain—moving your body. And it’s free. It’s not important what you do and where you do it. What counts is that you do something. Exercise will have an immediate effect on your well-being and your mental faculties, and you will notice the biggest effects after you have worked out regularly over a longer period.
No one would be happier than I if hanging out on the couch, eating potato chips, and binge-watching TV shows were the best we could do for our brain’s health. And it would be awesome if there were cognitive training methods and nutritional supplements that made me feel alert, happy, and focused all the time. Sadly, research clearly shows that this is far from reality. My brain is made for mobility. And just like yours, it will perform much better if we move our bodies!
Being physically active isn’t about being a jock or having six-pack abs; it’s about providing the brain with the most advantageous conditions so it can perform at its best.
10. THE RIGHT PRESCRIPTION FOR THE BRAIN
We’ve come to the most important part of the book, which I have left for the end. After looking at all the research on how exercise and training affect the brain, what can we define as the most beneficial activity level for the brain? How do we train to achieve maximum results? At the risk of becoming repetitive, I’ll say it again: there is no exact answer to that question, but we can still draw a few conclusions.
Most important, the brain counts every step! It’s better to move for thirty minutes rather than five minutes, but five minutes will count, too. Do something you enjoy!
You should walk for at least thirty minutes if you want good results.
The very best you can do for your brain is to run for forty-five minutes at least three times a week. It’s also very important to raise your heart rate.
Focus on cardiovascular training. Weight training does have positive effects on the brain, but aerobic training is better. If you like working out, don’t forget to include an endurance segment.
Interval training is good exercise, but less so from the brain’s standpoint because you become so tired that the immediate aftereffects are less beneficial. You won’t be more creative in the hours after interval training, but you will be after less strenuous training, such as running at a normal pace. That being said, interval training and other strenuous exercise is no doubt good for the brain over the long term, the reason being that intense effort strongly increases levels of BDNF.
Keep at it, keep at it, keep at it! The structural changes that come from the brain’s architecture being redrawn take time. An occasional run or walk will instantly provide better blood flow to the brain, but it takes time to create new brain cells and new blood vessels, and to strengthen the connections between the different areas of the brain—months, or even longer. Those who train regularly a few times a week for six months will notice the biggest change.
Yes, science is, in a sense, “reducing” us to the physiological processes of a not-very-attractive three-pound organ. But what an organ!
STEVEN PINKER
AFTERWORD
Inside your cranium, you have the most complex structure in the universe. An organ that is constantly active, from the day you’re born until you draw your last breath. An organ that is you. Because you are your brain. Why have I written a book about how the brain is affected by physical activity? Well, because modern neuroscience has shown that maybe the most important thing we can do for our brain—and therefore ourselves—is to be physically active. If this is not a story worth telling, then what is, I wonder?
However, writing a science book for general readership about how the human brain is affected by bodily movement is a challenge. After all, what we’re attempting to describe is an organ so enormously complex that we may never fully understand all its inner workings. Currently, neuroscience is advancing at the speed of light. Every year, about one hundred thousand scientific studies are published about the brain. That’s one study every four minutes, twenty-four-seven, year-round. Our knowledge increases, literally, by the hour. Despite this, we’ve just begun to scratch the surface.
It took scientists forty years to map the brain activities of the small roundworm (Latin name: Caenorhabditis elegans), one of the animals that has been used frequently in basic brain research. That is, if it’s even correct to call what it has a brain, since the tiny worm possesses about three hundred brain cells with a total of eight hundred connections between them. Compare that to a human brain’s one hundred billion cells with one hundred trillion (one thousand billion) connections.
In other words, there’s still a staggering amount we don’t know about how the brain works, and not least how it is affected by exercise. In this book, I’ve attempted to go over the picture that neuroscience presents at this moment. No doubt future studies will reveal many new, yet unknown, mechanisms by which the brain is strengthened through physical activity. However, I’m not in the least worried that this book’s main message won’t still be relevant in ten or even fifty years’ time. The benefits of exercise for your brain are enormous!
Neuroscience isn’t just a way to find causes and treatments for brain diseases; it also helps us to understand ourselves. Occasionally, research has managed to confirm things that seem obvious, like how important it is for us to socialize with others, or that alcohol breaks down the brain. Sometimes the discoveries have been surprising. We don’t need studies to tell us that we feel good from being physically active. However, the fact that exercise has such a big effect on our cognitive abilities (like creativity, stress tolerance, focus, and even intelligence) and that it might be one of the most important things we can do may not be quite so obvious. In fact, very few people seem to be aware of thi
s.
This book is not about my opinions or hopes, but about science showing what is. At the same time, it’s important for me to emphasize that this is not a scientific report, but a book on science aimed at a general audience. As such, I’ve had to simplify certain concepts to make the book more readable and interesting. I’ve included an index listing the research this book is based on, so those who want to dig deeper and get a more complete picture of how physical activity affects the brain can go to the source and find out even more. But before doing that, put down this book, and get out there and move—exercise your brain!
A MINI GLOSSARY
ACCUMBENS NUCLEUS also NUCLEUS ACCUMBENS A small part of the brain that is important for our reward system and for controlling our behavior. Dopamine is an important part of the nucleus accumbens, and we feel good when the levels of dopamine rise in that spot.
AMYGDALA An almond-sized area of the brain that is important for feelings of fear and emotional reactions. There are two amygdalae, one in each side of the brain. It belongs to the “reptilian brain”—the primitive parts of the brain that have remained throughout evolution. It is responsible for quickly putting the body on alert—fight-or-flight mode!
The Real Happy Pill Page 19