(HealthDay News) – Although more trials have been conducted on the effect of exercise in treating depression since the previous Cochrane review in 2009, the evidence is inconclusive, and further larger trials are needed, according to research published online Sept. 12 in The Cochrane Library.

Gary M. Cooney, of the Royal Edinburgh Hospital in the United Kingdom, and colleagues conducted a meta-analysis using data from 37 randomized, controlled trials to examine the effects of exercise as a treatment for depression in adults older than 18 years.

The researchers found that the quality of some of the studies was poor, which limits the strength of the findings. For the 35 trials comparing exercise with no treatment or a control intervention, a moderate clinical effect on depression was observed. When data from only high-quality trials were included, the effect of exercise on depression was small and not statistically significant. For the small number of studies comparing exercise with antidepressants or psychological therapies, no significant difference was observed in their ability to reduce the symptoms of depression.

“The evidence about whether exercise for depression improves quality of life is inconclusive,” the authors write. “Further larger trials are needed to find out whether exercise is as effective as antidepressants or psychological treatments.”

Two authors disclosed financial interests in exercise-related products and/or services.

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