Getting in a totally do-able number of hours of exercise a week may reduce the risk of depression, even in people who are genetically vulnerable to it, says a new study from Harvard University researchers at Massachusetts General Hospital.
It takes just 35 minutes a day of getting your heart rate up (for a total of only 4 hours a week) to get the benefits. Study participants saw a 17% decrease in their chances of experiencing periods of depression over the following two years. This “shielding” effect of exercise held true even for those at high genetic risk 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,” says Dr. Karmel Choi, of the Harvard T.H. Chan School of Public Health, in a release. “On average, about 35 additional minutes of physical activity each day may help people to reduce their risk and protect against future depression episodes.”
The study was published last week in the journal Depression and Anxiety.
Researchers looked at health data from about 8,000 participants in the Partners Healthcare Biobank, a long-term research project focused on how genes influence health. Participants had filled out surveys about lifestyle, including exercise. Next, researchers utilized millions of electronic health record data points to identify studied participants who had received diagnoses related to depression or had depressive episodes.
To determine the participants’ genetic risk of depression, researchers calculated index score that noted each person’s inherited risk for depression.
It was discovered that people with higher genetic risk were more likely to be diagnosed with depression over the next two years. Also, those who reported more physical activity were less likely to develop the condition, even after taking genetic factors into account. It seemed that a higher level of physical activity was found to be “protective,” even for people who already had a high genetic risk for depression.
By researchers’ calculations, it would just take four hours of exercise a week doing activities either high-intensity (running, aerobic activities), or low-intensity (yoga, etc.) to successfully ward off depression.
Dr. Choi sees the findings of this study as a hopeful and practical discovery that people can put to use in the real world. Depression is the leading cause of disability worldwide, according to the World Health Organization.
“We provide promising evidence that primary care and mental health providers can use to counsel and make recommendations to patients that here is something meaningful they can do to lower their risk even if they have a family history of depression,” says Choi.