A new study, published in the American Journal of Psychiatry, investigates the effect of physical activity on depression levels. The results of the random-effects meta-analysis examining baseline physical activity and incident depression indicate that higher levels of physical activity serve as a protective factor against the future development of depression.
“Our results indicate that higher levels of physical activity offer a protective effect on future development of depression for people of all ages (youths, working-age adults, elderly persons), and this finding is robust across geographical regions around the world,” the researchers report.
As one of the most common mental health disorders in the US, depression is a familiar experience for many people. While most often treated with selective serotonin reuptake inhibitors (SSRIs), this first-line treatment has been criticized as causing additional psychopathological and medical problems with long-term use. With mounting evidence cautioning the use of SSRIs, researchers are turning their attention to alternative treatments.
Non-Pharmacological Treatments (NPTs) for depression have been gaining support as safe and effective options for treatment and prevention. Treatments such as mindfulness, psychotherapy, and physical exercise are examples of common and well-researched alternatives to SSRIs for addressing depressive disorders.
“People with major depressive disorder are known to have a 50% odds of not meeting the recommended physical activity levels (e.g., performing >150 minutes of moderate-intensity physical activity each week) compared with people without major depression.”
While previous reviews have suggested that physical activity can be protective against the development of depression, the current study is the first pooled meta-analysis investigating this relationship. The pooled meta-analysis gives a more robust picture of the relationship between depression and exercise levels than an accumulation of separately analyzed studies.
For this project, Dr. Schuch and his team analyzed 49 studies which include over 200,000 individuals, with nearly equal sex distribution, various ages, and conducted across multiple geographical regions. Potential moderators such as sample size, length of follow-up, and study quality were investigated to see if these provided significant explanations of the variance in the effects of physical activity on depression. The researchers report the following results:
“Compared with people with low levels of physical activity, those with high levels had lower odds of developing depression (adjusted odds ratio=0.83, 95% CI=0.79, 0.88; I2=0.00). Furthermore, physical activity had a protective effect against the emergence of depression in youths (adjusted odds ratio=0.90, 95% CI=0.83, 0.98), in adults (adjusted odds ratio=0.78, 95% CI=0.70, 0.87), and in elderly persons (adjusted odds ratio=0.79, 95% CI=0.72, 0.86). No moderators were identified.”
While further studies are required to investigate the minimum physical activity levels required and the impact of different physical activity types, the current study provides an important contribution to a growing body of literature pushing for preventative measures dealing with depression. The researchers conclude:
“Our data further emphasize the importance of policies targeting increased physical activity levels. Randomized controlled trials are required to address whether or not physical activity can prevent the development of depression in those at high risk.”
Schuch, F. B., Vancampfort, D., Firth, J., Rosenbaum, S., Ward, P. B., Silva, E. S., … & Fleck, M. P. (2018). Physical activity and incident depression: a meta-analysis of prospective cohort studies. American Journal of Psychiatry, appi-ajp. (Link)