Study: Just One Hour of Exercise May Lower Depression Risk

We all know that exercise is good for the body and for heart health, but now a recent study indicates exercise also could have a positive effect on the risk for depression. 

In the study, published in the American Journal of Psychiatry, researchers sought to examine whether exercise protected against the onset of depression and anxiety and what intensity or amount of exercise people needed to produce this positive benefit. 

To do this, researchers tracked nearly 34,000 people who had no prior history of mental health or physical health issues over an 11-year period. They discovered that regular exercise reduced the risk of future depression but didn’t have the same impact on the risk for anxiety. They found that people who exercised for just an hour a week had a 44 percent lower risk for depression compared to people who weren’t physically active. 

This benefit was present regardless of the intensity of the exercise, so whether you do power yoga, CrossFit or simply walk several miles for one hour a week, it’s possible to lower your risk for depression. Interestingly enough, exercising for longer periods did not lead to greater decreases in depression risk, which means that exercising vigorously for two or more hours a week won’t have that much of an impact. However, it appears there are time constraints on the mental health benefits of exercise. According to the study’s lead author, these benefits only lasted for up to two hours. Still, researchers estimate that 12 percent of future cases of depression could have been prevented if participants in the study exercised for one hour every week.

The study didn’t shed more light on why just an hour a week of exercise can reduce depression risk or why physical activity produced this benefit for depression but not for anxiety. Generally, we know that exercise boosts mood and boosts levels of endorphins and serotonin, or feel-good hormones, in the body. There also are social benefits to exercise. While some people exercise alone, others may go to a gym or group fitness classes, which has the dual benefit of helping them get physically healthy and allowing them to engage with like-minded people who may turn into social acquaintances or friends. Getting in a great physical shape also can improve self-esteem, and this in turn can make someone have a more positive image of himself and a positive outlook on life. Exercise also is a great stress reliever. According to a recent poll conducted by the Anxiety and Depression Association of America, 14 percent of people say they exercise regularly to better cope with stress.

But all these things are just educated guesses. More research is necessary to determine why exercise — and that specific amount of physical activity — produces such a significant reduction in the risk for depression and why this impact doesn’t carry over to anxiety. But until that happens, it’s safe to say that exercise leads to improved physical health, and in some people, may improve mental health. That is reason enough to get moving — even if it is just for one hour a week.