How Exercise Affects Your Brain

by John Diaz

Unless you’ve been sleeping under a rock, a big rock you know that exercise is extremely beneficial to your heart, builds muscle and bone density and aids weight loss. Science is now showing us the effect exercise has on the brain, your brain, my brain, any brain for that matter and the results are pretty amazing.

A recent study done at the University of British Columbia found that aerobic exercise increased the size of the hippocampus, a region of the brain involved in memory, learning and stress control. Other studies suggest that the prefrontal cortex (executive center of the brain) is larger in people who exercise vs those that do not. Still other studies show global or all over brain changes possibly due to increased cerebral blood volume resulting from (you guessed it) exercise. 


As we age, generally after 40 years of age the brain begins to shrink. This might explain my inability to comprehend our youth’s obsession with reality TV stars. The shrinking is about 5% per decade and involves many areas of the brain particularly the frontal cortex, striatum, hippocampus and white and grey matter. Cerebral blood volume decreases as does neurogenesis as loss of neurons and blood pressure increase. Add to this the build-up waste products, formation of white matter lesions along with the decline of neurotransmitters dopamine and serotonin and you have a recipe for a dare I say…slow brain.    


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When our ancestors first climbed out of the trees and learned to walk upright they weren’t the strongest, the fastest or even the largest animal around, but what they had was the largest brain. Yes even the guy that cut you off in traffic…go figure. In order to survive they had to think on their feet while out on the hunt, remember what they did and what worked so they could do it again and then feel good about it so that they would want to again. It’s no coincidence that these 3 parts of the brain light up like a Christmas tree during exercise, it was basic survival.  

Aerobic exercise causes increased angiogenesis (increased vascular density) to occur. The likely cause is hypoxia (low blood oxygenation) during exercise. This increased vascularity is found predominantly in the hippocampus, motor cortex, cerebral cortex and cerebellum. Like angiogenesis neurogenesis has also been shown to increase with physical activity. Neurogenesis is the creation of neurons in the hippocampus and lateral ventricles. Two particular growth factors are up regulated with exercise BDNF (brain derived neurotrophic factor) and VEGF (vascular endothelial growth factor). VEGF promotes increased vascularity as well as the proliferation of new neural cells while BDNF promotes their survival and incorporation into the neural architecture. Exercise also has a positive effect on connectivity between deferent areas of the brain.


So, what do all these structural changes mean to you? In your younger years it means you can be at the top of your game with quicker decisions, better memory recall and an overall more dynamic brain. As you age the growth of new vascularity and neurons help bank against future neuron loss thus slowing decline and protecting against dementia and potentially Alzheimer’s disease.  Think of it as you do your body, the added muscle mass and bone density you get now from exercise protects you later as you get older against feebleness and osteoporosis. When you consider the longer lifespans we enjoy today the need to stay lucid and cognitive becomes greater.

Another area of benefit is the ability to handle stress better and this can affect someone of any age. A research team out of Princeton University found that cardiovascular exercise reorganizes the brain so that its response to stress is reduced and anxiety less likely to interfere with normal brain function.  Still not convinced? A study on depression published in The Archives of Internal Medicine found that aerobic exercise was as effective as Zoloft in treating mild to moderate depression. The Zoloft group exhibited swifter response, but the exercise group’s response lasted longer. In a follow-up study researchers checked on 133 patients from the original study 6 months later and found that those that continued to exercise were less likely to fall into depression. The likely cause is believed to be the increased release of endorphins and or norepinephrine.      


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A study published in The Journal of Ageing Research followed dozens of women in their 70”s and 80’s with mild cognitive impairment. This 6 month study found that women who exercised with either resistance training or aerobic exercise performed better on their cognitive tests vs a control group. Though weight training and aerobic exercise seemed to affect different types of memory (special vs language) both groups did far better than another group that did only stretching and toning exercises. That group showed a decline. At the start of the study the researchers were looking to see if decline could be slowed, but instead found to their surprise actual improvement.

An exercise routine of either aerobic exercise, resistance exercise, or both aerobic and resistance exercise for 30 minutes 5 times a week or 60 minutes 3 times a week would be prescribed. Start with just 10 minutes a day if you are a beginner and add from there. The key is to just not be sedentary.

Don’t overlook the importance of adequate sleep either. The glial cells that aid in communication between areas of the brain, but also help ride the brain of metabolic wastes. During sleep these cells go into hyper mode working like a pump to rid waste products.


As positive as this all is, an exercise program is only part of the equation. Though exercise creates a significantly better brain environment for new neuron growth utilizing those young neurons early with learning and novel experiences is key to their survival. Learning a new skill, a new language or a new subject is particularly beneficial to the exercised brain.  Parlez-vous-francais…just saying.    

REFERENCES: – The Effects of Aerobic Activity on Brain Structure – Exercise and Depression – Ageing and the Brain – Exercise reorganizes the brain to be more resilient to stress athletes-way – Why is Physical Activity so Good for Your Brain - Regular exercise changes the brain to improve memory, thinking skills – Getting a brain boost through exercise