Move Your Body, Build Your Brain

article by Shannon Dahlum

It’s well known that regular movement is vital for your physical health.  Exercise decreases your chances of developing type 2 diabetes and cardiovascular disease by fighting off insulin resistance and strengthening your heart.  Maintaining your strength and mobility as you age helps preserve a higher quality of life, but it likely increases your longevity, too.  Exercising your body is also important for supporting your mental health; the hormonal and biochemical responses that happen as a result of exercise help diminish stress and fight off depression and anxiety.  Not only does a consistent exercise practice support your physical and emotional health, but it also supports memory and cognition.  

A study done by the University of Illinois at Urbana-Champaign in November of 2014 showed that a growing emphasis on test scores in school children, at the expense of physical activity, actually led to decreased academic performance. Children who were physically active were found to have larger gray matter volumes in areas of the brain associated with cognitive control and memory.  Moving their bodies not only helped grow their muscles, but it appeared that it also helped physically grow their brains. 

In another study, British researchers evaluated more than 10,000 subjects aged 35-55, and graded their physical activity as either low, medium or high.  Sedentary individuals were more likely to display poor cognitive performance.  Those with low physical activity also had diminished capacity to think logically and solve problems in novel situations than their more active counterparts. 

Don’t be disappointed if getting in a thirty minute workout doesn’t automatically improve your daily Wordle score, though. Exercise doesn’t directly make you smarter or better able to focus, but it does optimize your brain for learning and focus by increasing brain-derived neurotrophic factor, or BDNF. 

BDNF is a protein that supports the growth, maturation and maintenance of your neurons.  It allows you to make new connections and learn new material.  It stimulates neurogenesis; the cell growth necessary to develop the brain in childhood and slow the aging process later in life.  In addition, BDNF is found in regions of the brain that control eating, drinking and bodyweight, and it likely contributes to the management of these functions. 

As you age, levels of BDNF decrease, which appears to cause shrinkage of gray matter and reductions in the number of synapses.  This leads not only to a smaller brain, but learning and forming memories becomes harder, as well. 

Changes in levels of BDNF also occur with psychological disease.  Depression and anxiety correlate with lower BDNF levels, while antidepressant medications may increase its expression and reverse shrinkage of the hippocampus.  Part of the mechanism of how antidepressants work may actually be due to the fact that they elevate BDNF.  A 2019 study found associations between low BDNF, anxiety, and binge drinking; indicating that those with lower BDNF levels may be more likely to suffer from alcoholism. 

Alzheimer’s and dementia patients have severely low BDNF, and some scientists think that boosting BDNF levels could help preserve their brain function.  Other evidence suggests the higher your BDNF, the lower your risk is for developing Alzheimer’s or dementia. 

Cannabinoids, like THC found in marijuana, temporarily increase BDNF levels in people who don’t regularly use it.  The same effects aren’t seen in chronic users, however.  Some studies have shown that regular marijuana use could have the opposite effect; it may directly decrease BDNF levels. For this reason, regular, long term use of marijuana may not only diminish memory and cognition, but it may also exacerbate or stimulate an earlier onset of psychological disease in vulnerable populations. 

Clearly, higher levels of BDNF is something you want to encourage when it comes to maintaining healthy brain function. Decreasing stress is one important element to preserving BDNF, so prioritizing healthy sleep patterns while avoiding processed foods, excess sugar and alcohol are all important.  In fact, all the healthy behaviors you already know that are important for preventing metabolic disease apply to maintaining healthy brain function, too, because obesity, insulin resistance and type 2 diabetes are all associated with lower BDNF levels.  Of course, this includes exercise. 

One bout of exercise creates an immediate response to BDNF levels, but results are even better with regular exercise.  Intense aerobic exercise (really getting that heart rate up) appears to be the most effective type of movement for increasing BDNF, but resistance training and high intensity interval training have also been shown to positively affect it.  Even moderate movement like standing and fidgeting can supercharge mental circuits and sharpen thinking skills, so if you’re stuck behind a desk most of the day, simply standing up while working can increase your mental performance. 

The environment in which you exercise seems to be just as important as the exercise itself when it comes to its effects on BDNF.  Multiple studies have found that unlike people who exercise in clean air, those who exercise in polluted environments (such as jogging or cycling near heavy traffic) don’t experience the increase in BDNF levels that would otherwise accompany physical activity.  Unfortunately, indoor environments are often even more polluted than the outdoors because of the chemicals present in the recirculating air.  In a perfect world, you’d be able to regularly get out in a wooded environment to enjoy movement in the fresh air.  Clearly, this isn’t always an option, but you can check the air quality index on your weather app before heading out.  Prioritize going outside to move on days when the air quality is good, and on days it isn’t, stick with the gym for some resistance training. 

Exercise prescriptions aren’t going away.  There is still no magic pill that’ll create physical or mental wellness in sedentary populations.  Eating unprocessed foods and moving your body regularly are the lynchpin for attaining and maintaining your health. For maintaining brain function as you age, movement becomes even more important.  Word puzzles and other cognitive challenges are great for keeping those mental gears spinning, but without physical movement to boost BDNF levels, you’re missing out on a key ingredient in maintaining a youthful brain.