Runners of all ages dressed as super heroes for the Action Ministries Action Dash in September 2012.
NBC NEWS -- Running, walking and other forms of activity can help people shake off the symptom of depression. Now, a new study in the American Journal of Preventive Medicine suggests that exercise may prevent the disorder later in life.
Researchers at the University of Toronto analyzed 26 years' worth of studies and concluded that even low levels of movement - walking or gardening for 20 or 30 minutes a day - show promise of warding off depression in people of all ages.
The analysis included 30 studies. Of those, 25 suggested exercise influenced depression risk. People who did little to no activity were more likely to show signs of depression or be diagnosed with the disorder years later, while those who exercised were less likely to become depressed as they got older, according to George Mammen, Ph.D. candidate and co-author of the study.
"I'm active so I wasn't surprised to find this, but 25 out of 30 showed a significant effect and that was unexpected," says Mammen.
Because small amounts (20 to 30 minutes a day) of low-intensity activity were associated with lowering depression risk, Mammen concludes that current activity guidelines for physical health appear appropriate for mental health as well. The Centers for Disease Control and Prevention recommend 150 minutes per week of moderate exercise (brisk walking) or 75 minutes of high-intensity activity (running).
"If you're not physically active, you should start," says Mammem. "We usually think of exercise in terms of weight and how we look, but it's also a way to maintain mental health far into the future."