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  • Writer's pictureClaire M. Burnett

Exercise & The Brain

Updated: Nov 25, 2018

16 days. 16 days without working out. It was the longest stretch I'd had in nearly a year and a half and while I'd love to tell you it was an amazing break; it wasn't. I was going a mile a minute and it wasn't that working out had been replaced by vegging, but that I'd spread myself entirely too thin without what I soon realized was a crucial outlet.

Exercise isn’t all about your body. In fact, building muscles and conditioning your heart and circulatory system are side effects. Exercise is really about your brain.

Made to Move…

Humans evolved to move, and that movement — hunting, running, climbing — spurred brain growth, especially in the prefrontal cortex, which differentiates us from other animals.

“Thinking is the evolutionary internalization of movement,” explains New York University neuroscience professor Rodolfo Llinás, MD, PhD. When you’re exercising, your brain is usually not what’s on your mind, but that activity is building your gray matter in myriad ways, making you more alert, creative, motivated, and perceptive, says John Ratey, MD, associate clinical professor of psychiatry at Harvard Medical School. It’s helping you learn better, remember more, and combat stress. It’s boosting your mood while helping you overcome anxiety and depression.

The real reason we feel so good when we get our blood pumping is that it makes the brain function at its best.

The reverse is also true, however: Inactivity is killing our brains.

Build a Better Brain

We now know that the brain is flexible, or plastic according to neuroscientists — more Play-Doh than porcelain. Our brains are constantly growing and they can even be rewired. Exercise is the key in that process.

Scientists understand that physical activity stresses our brains similarly to how it works our muscles. Neurons break down, then recover and become stronger and more resilient. “Aerobic exercise can change the brain’s anatomy, physiology — and function,” says New York University neural science professor Wendy Suzuki, PhD, author of Healthy Brain, Happy Life.

Numerous recent studies have revealed just how those changes occur. What’s becoming clear are the many neurological factors that activity positively influences, including the following.

Alertness and Perception

Exercise is potent. More nerve cells fire when we’re exercising than when we’re doing anything else. This activates the brain as a whole. It turns on arousal, attention, the frontal cortex, the executive functioning area — it makes us all set to participate in the world. Among these neurotransmitters are norepinephrine, which sparks attention, perception, motivation, and arousal; serotonin, which directs “traffic,” influencing mood, impulsivity, anger, and aggression; and dopamine, which governs attention and learning, plus our sense of contentment and reward.

Movement and Coordination

Exercise stimulates the cerebellum, which coordinates all the body’s motor movements, like standing upright, hitting a hockey puck, and performing a plié. When we exercise, particularly if the exercise requires complex motor movement, we’re also exercising the area of the brain involved in the full suite of cognitive functions.

Attention and Concentration

Our brains become more active when we are active; this causes neurons to fire in unison, creating brain waves. When we’re on autopilot — sleeping, brushing our teeth, watching TV — low-frequency waves prevail. High-frequency waves called beta waves dominate when we’re focused and processing information. Experts believe this enhanced focus comes from the bump in dopamine, which calms the mind.

Exercise and Mental Health

Beyond our cognitive abilities, exercise plays a profound role in our mental health. Some theorize that depression is caused at least in part by depleted levels of a category of neurotransmitters called monoamines, which include serotonin, norepinephrine, and dopamine — all of which are magnified by exercise.

“Going for a run is like taking a little bit of Prozac and a little bit of Ritalin because, like the drugs, exercise elevates these neurotransmitters,” says Ratey.

Exercise helps our brains balance hormones and it has other effects on mood, as well. Just as our muscles demand more energy during exercise, our brains gobble up glucose. In a 2016 study published in the Journal of Neuroscience, University of California, Davis, researchers discovered what the brain was doing with all that fuel: making more neurotransmitters.

The Best Outlet I Know…

As someone who struggles with depression, working out has been one of the best physical outlets I've found to manage my well-being. Crossfit became an outlet for me to focus on becoming the best version of myself while also being so heavily focused on giving everything I had in the moment; so much so, that there was no time for outward distraction.

With such busy schedules and lives, finding time to work out can be incredibly difficult. But I'd like to argue that the time we take to invest in our health is also time we'll get back in a host of other ways, whether it be working through problems more efficiently or the argument we don't have to work through because we were calm enough not to involve ourselves.

Either way, after 16 days of unintentionally not working out, I realized how incredibly important it was to my wholistic health, and I'm hoping that if you haven't already, you'll go give it a try and find out for yourself.

Want to know where I learned all this stuff? John Ratey, M.D. Check him out!

Got a question? Email me @


Coach B


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