Testing the clinical benefits of exercise is no small task. While placebos can be given in drug trials, there is no such equivalent for physical activity. A new study has raised controversy over its methods.
A controversial study has emerged over whether exercise is an effective treatment for depression, prompting an examination into claims about how physical activity affects mental illnesses. At the heart of the controversy is the fact that testing the effects of exercise are quite difficult given the gold standard of medical trials, i.e. a controlled experiment in which subjects do not know whether they are receiving the actual treatment or a placebo. With exercise, it is difficult to have unbiased control subjects because, unlike swallowing a placebo, treatment involves very active participation.
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What’s the Big Idea?
In determining whether exercise is an effective way to treat depression, it may be more helpful to turn to meta analyses which take stock of multiple studies at once. The Cochrane collaboration, a not-for-profit organisation that creates systematic reviews of health studies, has conducted such an analysis, finding that “on the whole, exercise has been shown to have some benefits for those with depression, but when only the very best-designed studies were included, this effect was very small.” Because exercise releases feel-good chemicals in the body known as endorphins, it is known to be a mood enhancer, but the complexities of clinical depression are not so easily resolved.