CityReads│Every Exercise I Do, I Do It for My Brain

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Every Exercise I Do, I Do It for My Brain

The point of exercise is to build and condition the brain. Exercise is the single most powerful tool you have to optimize your brain function.

John Ratey, Eric Hagerman, 2008. Spark：the revolutionary new science of exercise and the brain, Little, Brown and Company

Why we exercise?

In 2012, I visited Hong Kong for a year. When I was browsing the new books in the library, I encountered a book, Spark: the revolutionary new science of exercise and the brain, which completely changes my view on exercise. It was a turning point in my life. I spent first half of my life hating exercise because I failed all PE classes at school. It turns out I was only hating my PE class but not exercise. In the second half of my life, I start running regularly. This February I finished my fourth marathon. I am a mediocre runner at best. But it does not prevent me from getting the benefits that exercise can produce.

Different from other books on exercise and well-being, Spark makes a strong argument that the point of exercise is to build and condition the brain. Indeed, the sedentary character of modern life is a disruption of our nature, and it poses one of the biggest threats to our continued survival. What’s even more disturbing, is that inactivity is killing our brains too — physically shriveling them.

To keep our brains at peak performance, our bodies need to work hard. Exercise unleashes a cascade of neurochemicals and growth factors that can reverse this process, physically bolstering the brain’s infrastructure. In fact, the brain responds like muscles do, growing with use, withering with inactivity. The neurons in the brain connect to one another through “leaves” on treelike branches, and exercise causes those branches to grow and bloom with new buds, thus enhancing brain function at a fundamental level.

In Spark, the authors demonstrate how and why physical activity is crucial to the way we think and feel. They also explain the science of how exercise cues the building blocks of learning in the brain; how it affects mood, anxiety, and attention; how it guards against stress and reverses some of the effects of aging in the brain; and how in women it can help stave off the sometimes tumultuous effects of hormonal changes. Finally, the authors give suggestions on how to exercise in order to optimize your brain function.

Your life changes when you have a working knowledge of your brain. It takes guilt out of the equation when you recognize that there’s a biological basis for certain emotional issues. On the other hand, you won’t be left feeling helpless when you see how you can influence that biology. if you understand how physical activity improves brain function, you’ll be motivated to include it in your life in a positive way, rather than think of it as something you should do.

Brain is plastic

Brain is an adaptable organ that can be molded by input in much the same way as a muscle can be sculpted by lifting barbells. The more you use it, the stronger and more flexible it becomes.

Everything we do and think and feel is governed by how our brain cells, or neurons, connect to one another. What most people think of as psychological makeup is rooted in the biology of these connections. Likewise, our thoughts and behavior and environment reflect back on our neurons, influencing the pattern of connections. Far from being hardwired, as scientists once envisioned it, the brain is constantly being rewired. I’m here to teach you how to be your own electrician.

For the better part of the twentieth century, scientific dogma held that the brain was hardwired once fully developed in adolescence, meaning we’re born with all the neurons we’re going to get. We can rearrange synapses all we like, but we can only lose neurons. A study in 1998 showed that neurons were dividing and propagating — a process called neurogenesis — just like cells in the rest of the body. With that, they formalized one of the biggest discoveries in neuroscience.

Neurons are born as blank-slate stem cells, and they go through a development process in which they need to find something to do in order to survive. Most of them don’t. It takes about twenty-eight days for a fledgling cell to plug into a network, and if we don’t use the newborn neurons, we lose them.

Exercise spawns neurons, and the stimulation of environmental enrichment helps those cells survive. There is a solid link between neurogenesis and learning. Exercise provides the brain with the right tools to learn, and learning encourages those newly developing cells to plug into the network.

Aerobic exercise and complex activity have different beneficial effects on the brain. While aerobic exercise elevates neurotransmitters, creates new blood vessels that pipe ingrowth factors, and spawns new cells, complex activities put all that material to use by strengthening and expanding networks. The more complex the movements, the more complex the synaptic connections. And even though these circuits are created through movement, they can be recruited by other areas and used for thinking

How to optimize your brain function via exercise?

Exercise is the single most powerful tool you have to optimize your brain function. It is helpful to combine different categories of intensity in your exercise routine: low-intensity (exercising at 55 to 65 percent of your maximum heart rate), moderate-intensity(exercising at 65 to 75 percent of your maximum heart rate), and high-intensity (exercising at 75 to 90 percent of your maximum heart rate) exercise.

Our genes are coded for this activity, and our brains are meant to direct it. Take that activity away, and you’re disrupting a delicate biological balance that has been fine-tuned over half a million years. Quite simply, we need to engage our endurance metabolism to keep our bodies and brains in optimum condition. The ancient rhythms of activity ingrained in our DNA translate roughly to the varied intensity of walking, jogging, running, and sprinting. In broad strokes, then, I think the best advice is to follow our ancestors’ routine: walk or jog every day, run a couple of times a week, and then go for the kill every now and then by sprinting.

Do some form of aerobic activity six days a week, for forty-five minutes to an hour. Four of those days should be on the longer side, at moderate intensity, and two on the shorter side, at high intensity, which clearly releases some of the important growth factors from the body that build up the brain. So, on the shorter, high-intensity days, include some form of strength or resistance training. In total, it is better committing six hours a week to your brain. That works out to 5 percent of your waking hours.

The process of getting fit is all about building up your aerobic base. The more you work your heart and lungs, the more efficient they become at delivering oxygen to your body and brain. With the increased blood flow, of course, comes the chemical cascades that produce serotonin, brain-derived neurotrophic factor (BDNF), and other nourishing molecules.

One of the key differences between moderate and high-intensity exercise is that once you get closer to your maximum, and especially when you get into the anaerobic range, the pituitary gland in your brain unleashes human growth hormone (HGH). HGH is the body’s master craftsman, burning belly fat, layering on muscle fiber, and pumping up brain volume. Researchers believe it can reverse the loss of brain volume that naturally occurs as you age.

The most important thing is to do something. And to start. Plato once said, “In order for man to succeed in life, God provided him with two means, education and physical activity. Not separately, one for the soul and the other for the body, but for the two together. With these two means, man can attain perfection”.

Fun facts

The brain is made up of one hundred billion neurons of various types that chat with one another by way of hundreds of different chemicals, to govern our every thought and action

About 80 percent of the signaling in the brain is carried out by two neurotransmitters that balance each other’s effect: glutamate stirs up activity to begin the signaling cascade, and gamma-aminobutyric acid (GABA) clamps down on activity.

Glucose is the major energy source for the muscles and the sole energy source for the brain. The brain is a conspicuous consumer of glucose, using 20 percent of the available fuel even though it accounts for only about 3 percent of our body weight.

Low-carb diets may help you lose weight, but they’re not good for your brain. Whole grains have complex carbohydrates that supply a steady flow of energy rather than the spike and crash of simple sugars, and they’re necessary to transport amino acids such as tryptophan into the brain.

The brain is made up of more than 50 percent fat, so fats are important too, as long as they’re the right kind.

While sex increases dopamine levels 50 to 100 percent, cocaine sends dopamine skyrocketing 300 to 800 percent beyond normal levels.

It turns out that marijuana, exercise, and chocolate all activate these same receptors in the brain.

Starting at about age forty, we lose on average 5 percent of our overall brain volume per decade, up until about age seventy, when any number of conditions can accelerate the process.

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