Exercise’s Antidepressant Effects

Strengthened

Unknown | 13th September 2013

Exercise may have a moderately beneficial effect on depressive symptoms, according to an updated literature review and meta-analysis.

However, investigators note that more high-quality studies are needed to elucidate the type and intensity of exercise that may be most effective and whether these benefits are durable.

“Our review suggested that exercise might have a moderate effect on depression,” review author Gillian Mead, MD, of the Centre for Clinical Brain Sciences at the University of Edinburgh in the United Kingdom, said in a statement. “We can’t tell from currently available evidence which kinds of exercise regimes are most effective or whether the benefits continue after a patient stops their exercise program,” she added.

The review was published online September 12 in the Cochrane Database of Systematic Reviews.

Optimal Dose, Exercise Type TBD

A previous Cochrane Review on exercise and depression found only limited evidence of benefit for exercise in depression, the reviewers say. However, more trials have been completed since then, leading the Cochrane team to take a second look.

Data from 37 randomized controlled trials were included in the meta-analyses. The severity of patients’ symptoms was assessed using standard scales of depression.

Among 35 trials (1356 participants) comparing exercise with no treatment or a control intervention, the pooled standardized mean difference (SMD) for the primary outcome of depression at the end of treatment was -0.62 (95% confidence interval [CI], -0.81 to -0.42), indicating a moderate clinical effect, the reviewers say. There was moderate heterogeneity (I² = 63%).

When investigators included only the 6 trials (464 participants) with adequate allocation concealment, intentionto- treat analysis and blinded outcome assessment, the pooled SMD for this outcome was not statistically significant (-0.18; 95% CI, -0.47 to 0.11).

The reviewers note that pooled data from the 8 trials (377 participants) providing long-term follow-up data on mood found only a small effect in favor of exercise (SMD, -0.33; 95% CI, -0.63 to -0.03).

The evidence base would be strengthened by further large-scale, high quality studies, the investigators note.

The reviewers also recommend that future studies look in more detail at what types of exercise could most benefit people with depression and the number and duration of sessions that would provide the most benefit.

“Bizarre” Finding

The updated review also found “inconclusive” evidence that exercise for depression improves quality of life. “I find this very surprising,” T. Byram Karasu, MD, who was not involved in the review, told Medscape Medical News. “It’s bizarre, actually, because it has been shown that exercise for depression does improve quality of life.”

Dr. Karasu is professor and chair of psychiatry and behavior sciences at Albert Einstein College of Medicine and is psychiatrist-in-chief at the Montefiore Medical Center in New York City. He said it is important to distinguish “curative and useful activities.”

“If you have pneumonia, it’s useful to get fresh air, but it won’t cure pneumonia. You need an antibiotic for that. Exercise won’t cure minor depression, but it’s helpful in making you feel good about yourself,” he said. “Whether you are sad or not sad, healthy or not healthy, everyone should be exercising.”

Dr. Karasu also cautioned that exercise itself “wouldn’t be expected to relieve depression unless it is done at a level to generate endorphins, which means running at a speed of 6.5 to 6.7 miles per hour for at least 10 minutes.”

“I seriously doubt most depressed patients can do this; some can’t even get out of bed. Even the average nondepressed person cannot run at this level to generate endorphins. But for depressive mood, any exercise will help bring you out of a gloomy state; social activities will also help,” Dr. Karasu said.

The study was supported by the National Institute for Health Research. The authors report no relevant financial relationships. Dr. Karasu chaired the American Psychiatric Association work group on major depressive disorders, whose findings were published in Practice Guideline for Major Depressive Disorder in Adults (First Edition). Cochrane Database Syst Rev. 2013;9:CD004366. Abstract Medscape Medical News © 2013 WebMD, LLC Send comments and news tips to news@medscape.net. Cite this article: Exercise’s Antidepressant Effects Strengthened. Medscape. Sep 13, 2013. http://www.medscape.com/viewarticle/810949_print