Depressed? Take a hike.

Research suggests that the benefits of regular exercise can be powerful and comparable to those of an antidepressant for mild to moderate depression, according to Johns Hopkins Medicine.

Researchers at Duke University randomly divided 202 adults diagnosed with major depression (average age 53) into four groups. Two groups engaged in aerobic exercise three times a week: one group at home and the other in a supervised class setting. The routine was a 10-minute warm-up followed by a half hour of walking or jogging on a treadmill and five minutes of cool-down exercises. The other two groups didn't exercise but were given a typical daily dosage (50 to 200 mg) of the antidepressant sertraline (Zoloft) or a placebo.

Overall, 41 percent of participants achieved remission of depression after four months of treatment, and the percentage of each treatment group that reached this outcome was similar: 47 percent of the Zoloft takers, 45 percent of the supervised exercisers, and 40 percent of those who worked out at home. The placebo response was also considerable (31 percent), a reminder that some of the benefit of depression treatment -- whether medication, psychotherapy, or exercise -- is due to favorable expectations from patients and the attention that accompanies the treatment and being in a study.

How does it work?

It's hard not to feel good -- or at least better -- after exercising. On a psychological level, taking care of your body bolsters self-confidence and imparts a sense of self-control. It also promotes a positive body image, especially important if you're struggling with weight gain, a potential side effect of antidepressants.

Physiologically, exercise increases the flow of oxygen throughout the body, stimulates the nervous system, and affects levels of brain chemicals like serotonin, which, in turn, relieve tension, induce calm and make it easier to handle anxiety and stress. In addition, hormones called endorphins are released by the pituitary gland during exercise, creating a sense of well-being.

It sure can't hurt.