So exercise grows the brain and helps regulate it. Plus the younger we start the earlier the benefits are. But what if you’re (as a random example having nothing to do with the author) in your mid-thirties and struggling with stress, self-worth, and focus. You haven’t exercised in years. Maybe you never really did.

Are you stuck with the brain you’ve got, unaided by all that great stretching, growing, exercise I mentioned last time? No. And not only no, but an emphatic “absolutely not!”

Studies as recent as this year have shown that you still benefit from what Dr John J Ratey (Remember him? Wrote that great book, Spark?) describes as “Miracle-Gro for the brain,” as you age. In fact, the benefits may increase the older you get.

Hang on to that idea that it’s “never too late to grow the brain.” We’re going to revisit it in the final chapter.

So you aren’t a kid any more. You’ve got some life behind you and your brain has some wear and tear to prove it. You’ve got some neural pathways that aren’t the most productive, or your brain isn’t the best at regulating BDNF, dopamine, or some other hormone or neurotransmitter.

Well if the brain needs exercise to grow, it certainly needs it to re-grow.


“That which doesn’t kill me, makes me stronger” could be restated as “stress which doesn’t overwhelm my body’s ability to recover, makes me stronger.” Exercise is stress, applied intentionally to strengthen the body.

Exercise also increases your stress threshold, while improving your ability to recover from stress damage.

The stress response is often referred to as the “fight or flight” response. Those two words refer to movement for a reason. Your amygdala, hypothalamus, and HPA axis are firing up systems useful for survival (movement) and shutting down systems that aren’t.

Your body is preparing to move, so if you can, let it. Complete the cycle and put those chemicals to use. You‘ll not only “burn off” the waste buildup from your stress response, you’ll increase your brain’s stress capacity for next time.

Chronic stress can shrink parts of your brain and scramble your ability to turn the response on and off again. Through the application of exercise – intentional stress – we can raise our threshold and help our brain recalibrate its response.

Depression & Anxiety

Depression damages the brain. Just like stress, chronic depression shrinks areas of the brain. Once again, exercise is here to help the brain recover and heal. What grows, re-grows.

Exercise helps regulate neurotransmitters. We covered that last time. Just like with ADHD, most major depression medications target neurotransmitters that are affected by exercise. For depression these are serotonin plus our old friends norepinephrine and dopamine. It’s no surprise that many doctors are using exercise prescription in tandem with medication to treat depression.

There’s also this great little peptide called ANP. You can make it in the brain, but your heart also secrets it during intense exercise. ANP is a very chill peptide, and once it migrates up to the hypothalamus it helps regulate your HPA axis. You may recall that’s part of your stress response system. ANP is linked to reductions in anxiety symptoms, panic attacks, and helping reverse the negative effects of chronic stress.

Another big effect of exercise on anxiety is in the area of anxiety sensitivity. Anxiety sensitivity is the onset of anxiety when there is no trigger, only the symptoms. Your heart races or your breath quickens and the brain knows these things are signs of an anxiety episode. So it goes ahead and flips all the switches. Your brain is just trying to be helpful.

Intense exercise gives your brain a chance to experience increased heart rate or quickness of breath as normal signs of exertion, divorced from anxiety and fear. Over time, stress stops being solely associated with anxiety and the sensitivity often decreases.


Addiction shares a neurotransmitter issue with ADHD and depression. Dopamine. In fact, both ADHD and depression often contribute to substance abuse or other addictive behavior.

So exercise not only helps with dopamine regulation, but also with creating new sense memories, healing damage to the brain, and helping with underlying issues like depression or ADHD.

Remember ANP, that chill little peptide commuting from the heart to the HPA axis? A 2013 study specifically linked it to reduction of stress, anxiety, and craving symptoms for patients going through withdrawal.

Take Away

As I said earlier: what grows, re-grows. Stress is good for your body and mind, if you can recover from it. Exercise helps increase your stress threshold, create new neural pathways, and physically cope with the stresses of life.

Your brain needs to build its way out of a problem, and exercise gives it the tools to do that. It never stops growing, unless you stop moving.

Interested in learning more? Check out the rest of the Exercise and the Brain series:

Part one: Introduction and Overview

Part two: Growth

Part four: Longevity

Hyatt Training Portland personal trainer Max SteeleAuthor Max Steele is an ACE certified personal trainer and Precision Nutrition level 1 coach at Hyatt Training. He believes in the transformative power of sustainable nutrition, strength training, & game night. He aims to reignite self-discovery in those who doubt their capabilities and to prove the crucial role of “play” in the pursuit of deep health. Learn more about Max, or get in touch with him by emailing us at

Hyatt Training is a team of certified, enthusiastic and innovative personal trainers in Portland, Oregon. To read more fitness related posts like this one, follow this link.