Percent of patients in each condition six months after treatment.(Psychosomatic Medicine)
Depression is the most common mental illness—affecting a staggering 25 percent of Americans—but a growing body of research suggests that one of its best cures is cheap and ubiquitous. In 1999, a randomized controlled trial showed that depressed adults who took part in aerobic exercise improved as much as those treated with Zoloft. A 2006 meta-analysis of 11 studies bolstered those findings and recommended that physicians counsel their depressed patients to try it. A 2011 study took this conclusion even further: It looked at 127 depressed people who hadn’t experienced relief from SSRIs, a common type of antidepressant, and found that exercise led 30 percent of them into remission—a result that was as good as, or better than, drugs alone.
Though we don’t know exactly how any antidepressant works, we think exercise combats depression by enhancing endorphins: natural chemicals that act like morphine and other painkillers. There’s also a theory that aerobic activity boosts norepinephrine, a neurotransmitter that plays a role in mood. And like antidepressants, exercise helps the brain grow new neurons.
But this powerful, non-drug treatment hasn’t yet become a mainstream remedy. In a 2009 study, only 40 percent of depressed patients reported being counseled to try exercise at their last physician visit.
Instead, Americans are awash in pills. The use of antidepressants has increased 400 percent between 1988 and 2008. They’re now one of the three most-prescribed categories of drugs, coming in right after painkillers and cholesterol medications.