We can’t automatically assume that Olga’s brain was in better shape due to her training; it might already have been different right from the very beginning. However, her level of physical activity is a more plausible explanation for her brain’s good health.
Olga’s intense training is a perfect example of what scientists call successful aging of the body and brain. Olga Kotelko demonstrated that, from our brain’s perspective, it is never too late to start being physically active. The brain will get stronger no matter how late in life you begin exercising. And you don’t need to set your sights on breaking any world records or winning medals to obtain results.
Blue zones
There are a few regions in the world where an unusually high percentage of the population reaches the same age as Olga Kotelko—and even older—and who, like her, are untroubled by dementia. These mysterious places, which we have begun to call blue zones, go against the grain when compared to the rest of the world. There is a blue zone located in Sardinia, Italy, one in Okinawa, Japan, one in Costa Rica, and one in the Swedish region of Småland.
What is their secret? How can so many people reach one hundred years of age and not suffer from dementia? When scientists attempted to find the common denominator for these places, something interesting turned up. To start with, none of the blue zones are in big cities, but in small communities or on faraway islands. The people maintain strong social bonds, with several generations often living together. Very few live alone. Additionally, the people in these communities don’t stuff themselves with food but consume a strict diet with fewer calories (without it being a starvation diet). Another common factor is that the populations in the blue zones are very active; their exercise tends to consist of everyday activity, not hard training.
Scientists don’t know which factor (or factors) plays a part in longevity and the absence of dementia in these specific areas; it’s probably a combination of several elements. What is fascinating is that people in blue zones have, on average, lower levels of education, although we know that more education is protective against dementia. That physical activity contributes to advanced age is not merely a possibility, then, but very likely. It’s also interesting to note that these populations enjoy all the benefits of physical activity—long lives free of dementia—without needing to train hard. It seems that their everyday activities keep them from harm. That right there is a very good reason for taking a daily walk, for always taking the stairs, and for getting off the bus one stop or two before you reach your destination.
THE RIGHT PRESCRIPTION TO APPLY THE BRAKES ON THE BRAIN’S AGING
All activity matters! Your body takes account of every step, especially when it comes to the aging of the brain.
Walk for twenty to thirty minutes every day, at least five days a week. Or run for twenty minutes three times a week. Swimming and biking are just as good, so long as the level of exertion is the same.
Weight training is important to stay functional and mobile, but we don’t know yet if it has any effect on the aging of the brain. I recommend engaging in cardiovascular training before anything else, at least until we know more about the impact of weight training.
9. A STONE-AGE BRAIN IN THE DIGITAL AGE
Nothing in biology makes sense except in the light of evolution.
THEODOSIUS DOBZHANSKY
In this book, you’ve seen how exercise and physical activity can make you more focused, happier, and less anxious and stressed out; how it strengthens your memory; and how it makes you more creative and even seems to be able to increase your intelligence. You’ve discovered the mechanisms that transform your running into nothing less than a mental upgrade. Sure, it’s easy to become mesmerized by the research, but personally, I believe the most thrilling aspect of it all is not how our brain is affected by our being physically active—but why it happens.
If we want to know how to make our car run smoothly, we need to understand how it is made. Same goes for the brain. If we want to make our brain function better, it’s good to start by learning how it works. We don’t need to become neuroscientists or psychiatrists for that. The very best way to make sense of the brain is to see how it has developed. We need to backtrack and look at the history of the brain.
We’ll start from the very beginning. Lucy, whose skeleton was found in Ethiopia in the 1970s, is often considered to be our oldest known ancestor. It’s believed that she lived approximately 3.2 million years ago, and that her brain volume was about 0.5 liters (just under 17 fl oz), which is a bit more than a third of today’s average brain volume of 1.3 liters (just under 44 fl oz). If we fast-forward the tape by just over a million years, we’ll meet Homo erectus, who walked upright and who was one step ahead of Lucy and her brain size. His brain’s volume was just under 1 liter (1 quart), and his behavior had begun to change, too. Homo erectus knew how to build a fire and make tools, weapons, and clothes.
THE COGNITIVE REVOLUTION
The brain’s volume started to increase at a faster pace around one million years ago. This could have been due to better nutrition, with more protein. Barely one hundred thousand years ago, our ancestors’ intellectual capacity seemed to improve significantly—a phase that is commonly referred to as the cognitive revolution—which had great consequences. From a historical standpoint, an extremely short period saw our ancestors colonize large areas of the globe and go from being one rather inconsequential species among many others in a corner of East Africa to becoming masters of the Earth, without rival at the top of the food chain. On the way, they knocked six other human species out of the running (yes, there were at least six other different species in existence). Today, only our species, Homo sapiens, is still here. What made us win? We’re not entirely sure, but it didn’t just come from having a larger brain. The Neanderthals, for example, one of the six species we beat out, had a larger brain than ours.
One possibility is that our dominance is a result of differences in the cortex—the cerebral cortex—the outer cover of the brain. The cerebral cortex is comprised of six distinctive layers. The cerebral cortex is the center of our advanced cognitive functions. Mathematical, logical, linguistic, and creative thinking abilities can all be found in the cerebral cortex. This is the place in your brain where the magic happens. As the American astronomer Carl Sagan said, “Civilization is a product of the cerebral cortex.”
A larger and more sophisticated cerebral cortex—especially the area situated behind the cranium, in the frontal lobe’s anterior part (the prefrontal cortex)—translates to increased capacity and behavior flexibility.
This contributes to our big advantage for survival. We become better hunters, stronger at defending ourselves against our enemies, and, let’s not to forget, more amenable to working together. All this leads to better nutrition with more protein and vitamins, which in turn gives the cerebral cortex an opportunity to evolve even further. This makes the person smarter and better still at surviving and finding food, and so on.
Today, our brain looks a bit like long, tightly packed sausages. This is to free up more room for the cerebral cortex. If the brain were as smooth and polished as a billiard ball, the overall surface of the cerebral cortex would be smaller, making us considerably more primitive.
Did a badly copied gene make us smart?
The human brain is approximately three times the size as that of a chimpanzee’s, our closest relative. We split from this species six million years ago, and their brains appear to have marched in place ever since. During this time, the human brain tripled in size. Moreover, our cerebral cortex became disproportionately large compared to other animals, especially the frontal lobe and its anterior part, the prefrontal cortex.
But what was it that gave our ancestors a larger brain and an increasingly sophisticated cerebral cortex, and with it an edge over the other species? Many scientists believe the answer can be found in our genes.
THE BRAIN’S MOST IMPORTANT FUNCTION
In principle, only mobile living organ
isms possess a brain. Plants are not ambulant, so they don’t have a brain. It’s believed that the first brain cells were created about six hundred million years ago and that their primary task was probably to coordinate movement in primitive animals. This means that the first brain cells that emerged on Earth had movement as their most important function. At this point, the brain cells did not contribute to sophisticated brain functions like concentration, but to simpler reflexes, such as moving the organism from place to place in search of food.
The same applies to us humans. Coordination of movements has most likely been our brain’s most important function, and it still is. So, if the brain’s most important task is to get you to move your body, wouldn’t it be odd if movement in and of itself were of no importance to the brain? The body can’t move without a brain, and if the body doesn’t physically move, the brain can’t function as it was meant to.
In 2015, scientists from the Max Planck Institute introduced a gene that they believe might have contributed to the fact that you are sitting here reading this, instead of scouring the savanna trying to find animals to kill.
Genes often have complicated names, and this one is called ARHGAPIIB. It can be found in humans but is missing in related species like the chimpanzee. Interestingly, it looks like the gene came about purely by chance. When another gene was going to be copied in one of our ancestors, something went awry, and instead of a whole gene, only a fragment was copied. This fragment, which we today call ARHGAPIIB, had the ability to spur on the growth of the cerebral cortex. The ancestor, or ancestors, who by lucky accident was dealt the faulty genetic copy, got the slightly larger cerebral cortex, and thus the larger cognitive capacity, leading to an advantage in terms of survival. The gene was then passed down to offspring, whose cerebral cortex grew a bit more, which is how the brain has continued to develop through history.
Perhaps we have chance to thank for our intelligence. If the duplication had not been faulty and created ARHGAPIIB, we might never have made it to the moon, discovered the theory of relativity, or painted the Sistine Chapel—continuing instead to roam the savanna.
But how do we know it’s just this one gene that’s behind the expansion of the brain? Our genetic material contains about twenty-three thousand genes, so it could be just about any of them. Well, the answer is, of course, that it’s impossible to be 100 percent sure. However, a good indication that ARHGAPIIB could very well be behind this critical evolutionary step for us humans came up after we implanted the gene in mice, which don’t naturally possess ARHGAPIIB, using genetic technology.
Mice have a small cerebral cortex in relation to their body size, and the cortex has no folds; however, something happened to the mice who got the gene. They grew a bigger brain, and in several cases
the cerebral cortex also showed signs of folds. In other words, their brains looked more like ours! The real, important question here is, of course, if the mice became smarter. We don’t know the answer to this yet, but we’re working on it.
MORE MOVEMENT—BIGGER BRAIN?
Humans have a large brain compared to their body size. Its volume is approximately 1.3 to 1.4 liters (just under 44 fl oz to just over 44 fl oz), while a mammal weighing 60 kilograms (132 lbs) has an average brain volume of 0.2 liter (6.75 fl oz). This means that our brain volume is, on average, about six times as large as that of any other species. Also, an interesting correlation that scientists found when examining the brain sizes of different animals is that animals with good stamina—those that can run far—have a large brain. Like humans, rats and dogs have good stamina and, like us, they have large brains relative to their body weight.
Maybe this is because BDNF—which is created when you move—makes the brain grow and speeds up the creation of new brain cells. One possible explanation for this is that our more active ancestors were successful at finding food and surviving, and thus at propagating their genes. A lot of BDNF was generated during their physical activity, and, consequently, their brain grew. In turn, their children’s brains became a bit larger, and among those offspring, those who were more physically active survived; thanks to BDNF, they also grew a somewhat larger brain, too. This is how physical activity drove the evolution and growth of the brain, which means we can thank physical activity—at least partly—for our intelligence.
THE BIG SWITCH-OVER
No one is oblivious to the fact that over the last few years there’s been a development where we’re becoming less physical, spending more time in front of computers and smartphones. Even though this trend is as important as it is troubling, there are even more interesting connections to be found if we look further back in time. Sometime around ten thousand years ago, our ancestors turned to agriculture after having spent millions of years as hunter-gatherers. The hunter’s nomadic lifestyle, with its constant, active search for food, was swapped out for a lifestyle that required staying more or less in one place. Being a farmer certainly didn’t mean that you could sit around all day, but it is very likely that they were less physically active than our hunting ancestors.
The decrease in physical activity that occurred as we went from hunting to agriculture all those years ago is probably a trifle compared to what has happened over the last two hundred years, where big change has taken place in our activity habits. In just over two hundred years, we’ve gone from an agrarian society to an industrialized one—and today, a digitalized one—where most of us do not need to go out and actively gather food.
What was once our most important daily task over most of humanity’s history has become something most of us don’t have to worry about anymore, never mind being physically active in order to carry it out. Today, all our food is available at the grocery store and even online, where we can order it and have it delivered to our door to avoid having to move at all.
Half as many steps
These changes have had an enormous impact on our activity levels. Today, active people are probably far less active than the average person was two hundred years ago. So then, how much less active are we? It’s difficult to pinpoint the amount exactly, since our ancestors did not have access to pedometers to measure how much they moved around. But by examining the activity pattern of people who still live as hunter-gatherers and comparing it to that of farmers, it’s possible to make an educated guess.
The Hadza people live in north Tanzania. The tribe has about one thousand members, about half of whom live as hunter-gatherers. They have no domestic animals, they don’t cultivate the earth, and they don’t have permanent settlements. Instead, they subsist by hunting and building temporary shelters for the night. Their language is unique, and probably one of the oldest spoken languages on earth. Basically, the Hadza live the same way that their—and our—ancestors lived ten thousand years ago. They belong to the very last people on the planet who live as hunter-gatherers and are a rare link to our ancestors’ way of life.
How active are the Hadza people? When members of the tribe were fitted with pedometers, it showed that the men walked an average of 8 to 10 kilometres (5 to 6.25 miles) a day, which is the equivalent of about 11,000 to 14,000 steps (the women walked fewer steps). That is about the same amount we believe our hunter-gatherer ancestors walked.
And what about the farmers? For reference, we can observe the Amish people in the US, an agrarian society that lives pretty much as we did two hundred years ago. The Amish have chosen to forgo all modern amenities—they don’t watch television, are not connected to the internet, and don’t run electricity. They move considerably more than we do. The men walk about 18,000 steps a day while the women, like the women of the Hadza tribe, take a few fewer steps. Now compare this to the 6,000 to 7,000 steps that Americans and Europeans walk daily, on average, and you’ll see that the Hadza and Amish walk about twice as much as today’s population in the western world. It is entirely possible that we’ve cut our activity pattern in half during our transition from a hunter’s society to modern civilization.
In a blink of an ey
e
The ten thousand years that have gone by since we made the switch to an agrarian society might seem like an eternity. However, from a biological perspective, it is a very short time. Our period as farmers spans only 1 percent of the history of humankind. The approximately two hundred years that have passed since the beginning of industrialization can also feel like a stretch, since the 1800s are undeniably long past, but from an evolutionary standpoint, it is just the blink of an eye. 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 p.m., twenty seconds before midnight. We entered the digital age (i.e., we connected to the Internet) at 11:59:59—that is, at one second before midnight!
If we consider the time it takes for other species to develop, it’s obvious that evolution takes a long time. It’s common that ten thousand years, and often longer, pass before anything of significance takes place, which means that today’s people are generally genetically identical to those who lived one hundred, one thousand, and even ten thousand years ago.
Think about it: over a period that is basically a blip in our history, we’ve made gigantic changes in our lifestyle that have cut our need for physical activity in half. If we compare that to evolution’s development of humanity as a species—which happens slowly, more like in terms of tens of thousands of years—you can see that our lifestyle changes have far outpaced the evolution of our bodies and brains. Evolution is lagging. Biologically, our bodies and brains are still on the savanna, and we’re more hunter-gatherer than farmer. Add this to what you’ve read in this book so far—that your brain is strengthened by exercise; that it makes you happier, and less stressed and worried; that you become more creative and focused; that a lack of physical activity can lead you to become anxious, sad, and unfocused—and it’s easy to conclude that many of today’s common psychological problems stem from our lack of physical activity. We’re walking out of step with our biological age—or, should I say, we’re sitting out of step.
The Real Happy Pill Page 18
