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NEW YORK (Reuters Health) - Regular exercise may work as well as medication in improving symptoms of major depression, researchers have found.
In a study of 202 depressed adults, investigators found that those who went through group-based exercise therapy did as well as those treated with an antidepressant drug. A third group that performed home-based exercise also improved, though to a lesser degree.
Importantly, the researchers found, all three groups did better than a fourth group given a placebo -- an inactive pill identical to the antidepressant.
While past studies have suggested that exercise can ease depression symptoms, a criticism has been that the research failed to compare exercise with a placebo. This leaves a question as to whether the therapy, per se, was responsible for the benefit.
The new findings bolster evidence that exercise does have a real effect on depression, according to the researchers.
Doctors may not start widely prescribing exercise as a depression treatment just yet. But for patients who are motivated to try exercise, it could be a reasonable option, the study authors say.
"If exercise were a drug, I'm not sure that it would receive FDA approval at this time," noted study author Dr. James A. Blumenthal, a professor of medical psychology at Duke University Medical Center in Durham, North Carolina.
"But," he told Reuters Health, "there is certainly growing evidence that exercise may be a viable alternative to medication, at least among those patients who are receptive to exercise as a potential treatment for their depression."
The study, published in the journal Psychosomatic Medicine, included 202 men and women age 40 and older who were diagnosed with major depression. They were randomly assigned to one of four groups: one that worked out in a supervised, group setting three times per week; one that exercised at home; one that took the antidepressant sertraline (Zoloft); and one that took placebo pills.
After 16 weeks, the patients completed standard measures of depression symptoms.
By the end of the study, Blumenthal's team found, 47 percent of patients on the antidepressant no longer met the criteria for major depression. The same was true of 45 percent of those in the supervised exercise group.
In the home-based exercise group, 40 percent had their symptoms go into remission. That compared with 31 percent of the placebo group.
There are several theories on why exercise might improve depression. For example, physical activity seems to affect some key nervous system chemicals -- norepinephrine and serotonin -- that are targets of antidepressant drugs, as well as brain neurotrophins, which help protect nerve cells from injury and transmit signals in brain regions related to mood.
Exercise may also boost people's feelings of self-efficacy and promote positive thinking. Some experts speculate that group exercise, with its social aspect, may have added benefits.
Though the home exercise group in this study did better than the placebo group, it's not clear whether it's as good as supervised classes, according to Blumenthal. "Home exercise may be more convenient," he noted, "but patients not push themselves as hard on their own."
He added that supervised exercise may also be safer for some people, such as those with heart disease.
SOURCE: Psychosomatic Medicine, September 2007.