When it comes to alleviating depression, says Andrea Dunn, intensity makes little difference. It's not only unnecessary to go for the burn, it's unwise; too-vigorous exercise raises the risk of stopping altogether. But exactly how much energy expenditure needed is not clear. Nor is it known whether there's a "threshold effect,"—a minimum level of exercise needed to provide any antidepressant benefit.
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"Our data show that 30 minutes of aerobic exercise three times a week is sufficient for reducing depressive symptoms," says James Blumenthal. Thirty minutes thrice weekly is the minimum recommended for cardiovascular benefit.
Exercising more often may have value, but it might set the bar too high for depressed people. What's important is getting people to be physically active. "We know that behavioral activation is a very important component of cognitive behavioral therapy," says Blumenthal. "Physical activity may be not just a necessary component but a sufficient component."
