By Mark Gold, MD
As depression becomes a leading cause of disability worldwide, it is even more imperative to focus upon effective preventative measures. Findings from a recent study strengthen the empirical support, and provide the most compelling case yet, for physical activity as an effective prevention strategy for depression. Read further to find out more on how physical activity can influence risk of depression and how this can shape the future of depression prevention and treatment. Exercise is known to be effective stress relief - higher levels of physical activity can potentially inhibit the risk of developing mental illness. As building evidence further fortifies this theory, a new study by the research team at Harvard Medical School, led by Karmel W. Choi, PhD, postdoctoral fellow at the Harvard T.H. Chan School of Public Health and Harvard Medical School’s Massachusetts General Hospital, has discovered that robust physical activity is an effective treatment for depression.
The exercise effect
Exercising initiates a surge of biological circumstances that yield numerous health benefits, such as protecting against heart disease and diabetes, improving sleep patterns and lowering blood pressure. High-intensity exercise is known to release the body’s feel-good chemicals, known as ‘endorphins,’ creating a euphoria.
However, it is long-term exercise that yields the highest value - sustained activity releases proteins called neurotrophic or growth factors, which lead to nerve cells to grow and build new connections. This improvement in brain function makes an individual feel better, especially when it comes to individuals struggling with depression. Since exercise enhances nerve cell growth in the hippocampus, it can improve nerve cell connections and consequently relieve depression.
Physical activity: a promising avenue
The results of this study indicated that objectively measured increased physical activity protected against the risk of depression, but not the self-reported activity. This may largely be due to the fact that self-report measures are exposed to inaccuracies stemming from mood states and cognitive biases, that also influence mental health. Furthermore, objective readings are enabled to record activity other than planned exercise, such as walking to work or climbing the stairs. Hence, a depressed individual may view themselves as more inactive and lethargic than they actually may be.
“On average,” Choi says, “doing more physical activity appears to protect against developing depression. Any activity appears to be better than none; our rough calculations suggest that replacing sitting with 15 minutes of a heart-pumping activity like running, or with an hour of moderately vigorous activity, is enough to produce the average increase in accelerometer data that was linked to a lower depression risk.”
Looking to the Future
One in 10 adults in the United States struggle with major depression and many others are affected to varying degrees. With so many affected, there is a need to better manage major depression and its increasing burden of disability and mortality. Antidepressants have not proven effective universally and most patients are subjected to a trial-and-error process to determine the regimen best suited to their individual needs, so while these medications are an important tool, it’s important for us to explore further any other promising options for treating depression.
More and more findings are establishing links between physical activity and mental health. Having established that exercise is beneficial, the next important step should be in the direction of increasing the uptake and encouraging conformity to exercise. This knowledge is indeed important as it will allow us to focus on and invest in preventive strategies that are actually effective.
Choi KW, Chen C, Stein MB, et al. Assessment of Bidirectional Relationships Between Physical Activity and Depression Among Adults: A 2-Sample Mendelian Randomization Study. JAMA Psychiatry. Published online January 23, 2019. doi:10.1001/jamapsychiatry.2018.4175
Dr. Mark S. Gold is a teacher of the year, translational researcher, author, mentor and inventor best known for his work on the brain systems underlying the effects of opiate drugs, cocaine and food. Read more by Dr. Gold here.