They randomly assigned depressed men and women aged fifty or older to either begin an aerobic exercise program or take the antidepressant drug sertraline (Zoloft). Within four months, the mood of those in the drug group improved so much that they were, on average, no longer depressed. But the same powerful effect was found in the exercise group—that is, the group of people who weren’t taking any drugs. Exercise, it seemed, works about as well as medication.
