Physical Activity Reduces Odds of Depressive Episode

Jordan Smoller, MD

Increasing physical activity could pay dividends for people with a high risk of developing depression.

A team from Massachusetts General Hospital (MGH) recently discovered that several hours of weekly exercise result in a decreased chance to be diagnosed with a new episode of depression, even in patients with a higher genetic risk of developing Major Depressive Disorder (MDD).

The team examined the genomic and electronic health record (EHR) data of approximately 8000 patients in the Partners Healthcare Biobank, which represents the first study to show how physical activity influences depression despite genetic risk.

In the study, the team followed patients who filled out a survey about their lifestyle habits—including physical activity.

The investigators then mined millions of EHR data points over a 2-year period and identified patients who received a diagnosis related to depression based on 2 or more diagnostic billing codes for a depressive disorder. They also calculated the genetic risk scores for each participant by combining data across the entire genome into a single score that reflects a person’s inherited risk for depression.

The investigators discovered that patients with a higher genetic risk for depression were more likely to be diagnosed with depression over the next 2 years. However, more physically active patients at baseline were less likely to depression, even after they accounted for genetic risks.

Additionally, higher levels of physical activity were protective for patients, even for those with the highest genetic risk scores for depression.

"Our findings strongly suggest that, when it comes to depression, genes are not destiny and that being physically active has the potential to neutralize the added risk of future episodes in individuals who are genetically vulnerable," Karmel Choi, PhD, of MGH and the Harvard T.H. Chan School of Public Health, and lead author of the study, said in a statement. "On average, about 35 additional minutes of physical activity each day may help people to reduce their risk and protect against future depression episodes."

Both high-intensity exercise like aerobics, dance, and exercise machines, and lower-intensity activities like yoga and stretching, were tied to decreased rates of depression.

Overall, individuals saw a 17% reduction in odds of a new episode of depression for each 4-hour block of activity added per week.

The study could allow clinicians to better prevent depression and other mental health conditions for high risk patient populations.

"In general our field has been lacking actionable ways of preventing depression and other mental health conditions,” senior author Jordan Smoller, MD, said in a statement. "I think this research shows the value of real-world healthcare data and genomics to provide answers that can help us to reduce the burden of these diseases."

The investigators also plan to explore modifiable ways to reduce the risk of depression as part of an overall strategy for improving resilience and preventing depression.

“Real-world data from a large healthcare system suggest that individuals with high genetic vulnerability are more likely to avoid incident episodes of depression if they are physically active,” the authors wrote.