Long before weight-loss and exercise guru Richard Simmons jumped and flexed across television screens in the 1980s, it was clear that exercise is good for the body. From helping to maintain a healthy weight, to moving oxygen through the blood, to increasing flexibility, the benefits of exercise on the human physique are seemingly endless.
But what about the benefits of exercise to the brain? The epicenter of the human nervous system, the brain controls movement, development, decision-making, thoughts, and emotions. And common sense tells us if exercise is good for the body, it must be good for the brain. Right?
Right. In her July article for CNN.com, writer Kristen Domonell quoted Dianna Purvis Jaffin, Ph.D., director of strategy and program at the Center for Brain Health's Brain Performance Institute in Dallas, TX. "What benefits the body benefits the brain," Jaffin said. "You are not a separate brain walking around on top of a body."
According to Jaffin, exercise accelerates “complex processes inside your mind that can curb depression.”
Domonell explained that the brain contains roughly 86 billion neurons, “designed to bark orders to the rest of your body . . . [via] chemical messengers called neurotransmitters”. Neurotransmitters control “everything from your mood and sleep cycle, to memory and appetite”.
She also cited the work of University of California Davis Medical Center researcher Richard Maddock, M.D.—a study measuring the neurotransmitter levels of experiment participants before and after taking part in 20 minutes of exercise of moderate intensity. Maddock reasoned that since the result of low concentrations of two of the brain’s key neurotransmitters (glutamate and gamma-aminobutyric acid (GABA) can cause depression—perhaps exercise could raise their levels.
Maddock and his team of researchers published their “good news” outcomes in the February 2016 edition of The Journal of Neuroscience. “The result, whether you suffer from depression or not,” wrote Maddock for the journal, “is an increased resilience and capacity to respond to mental challenges, a concept known as mental fitness”.
Jaffin echoed Maddock’s good news, focusing on her own studies of the benefits of exercise to the brain. Comparing the good and bad effects of stress, Jaffin said life’s everyday stressors cause the brain to emit cortisol--its fight or flight hormone. “This is good if you're about to get mugged on the street,” she said, “but if your cortisol levels are chronically elevated, it can cause problems [including memory loss and high blood pressure]”.
Exercise introduces a positive effect on the brain--something Jaffin calls controlled stress. As a result of the exercise then, the brain’s response to stress becomes something that can be switched on and off, instead of elevated all the time.
In a 2016 article for The New York Times, author Gretchen Reynolds reported on three analyses of exercise and the brain, together encompassing over one million male and female study participants. “Scientists have long questioned whether and how physical activity affects mental health,” Reynolds wrote. “While we know that exercise alters the body, how physical activity affects moods and emotions are less well understood.”
After evaluating the results of the more than 1,140,000 test participants [in the three experiments], Reynolds said, “the links between fitness and mental health turned out to be considerable”. She wrote that, in fact, researchers Schuch et al found “those men and women with the lowest fitness were about 75 percent more likely to have been given diagnoses of depression than the people with the greatest fitness”.
Reynolds explained that for the most “innovative” of the three different studies, scientists directed their focus on whether exercise had the ability to prevent depression from occurring or developing. Their results were printed in Preventive Medicine in December 2016.
In a completely unconnected study, many of the same researchers examined whether exercise could be seen as a treatment to reduce depression. The evaluation of this study was published in the Journal of Psychiatric Research in June 2016. According to their assessments, the researchers concluded that “[people’s] mental health tended to demonstrably improve if they were physically active”.
In a November article for the American Psychiatric Association’s Psychiatric News, writer JoAnn Blake reported on the findings of a large population study published in October in the American Journal of Psychiatry’s [AJP] in Advance. “Research over the years has shown that regular physical activity can help relieve depression, but this study may be the first to recommend a specific dose of exercise,” she wrote.
Based on a study that followed almost 34,000 Norwegian adults over an 11-year period, results showed even “low levels of exercise” [e.g., walking, cycling] provided mental health protection from depression. Of interest to Blake was that this study did not prove exercise prevented anxiety. Nevertheless, researchers concluded that “combined physical and social benefits of exercise may mediate the protective effects against depression, according to the study”.
Studies and results continue to provide support for exercise as prevention and treatment of such mental illnesses as depression. And while the benefits to mental health are well documented, researchers and professionals continue to advise anyone considering participation in new or strenuous physical exercise to first consult a physician.
References
Blake, J., (November 30, 2017). Psychiatric News. American Psychiatric Association. Minimal Exercise May Help Prevent Future Depression https://psychnews.psychiatryonline.org/doi/full/10.1176/appi.pn.2017.11a11
Domonell, K., (July 26, 2017). CNN. How workouts give your brain a boost. http://www.cnn.com/2016/04/29/health/exercise-benefits-brain/index.html
National Institute of Mental Health. (June 9, 2011). Stress-Defeating Effects of Exercise Traced to Emotional Brain Circuit. https://www.nimh.nih.gov/news/science-news/2011/stress-defeating-effects-of-exercise-traced-to-emotional-brain-circuit.shtml
Reynolds, G., (November 16, 2016). New York Times. How Exercise Might Keep Depression at Bay. https://www.nytimes.com/2016/11/16/well/move/how-exercise-might-keep-depression-at-bay.html
Rodriguez, T., MA, LPC., (December 13, 2017). PsychiatryAdvisor.com. Effectiveness of Exercise in Decreasing Depressive Symptoms.
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