Sept. 26, 2000 -- We've all heard that exercising regularly is a good way of beating the blues. Now, new research suggests it may help keep depression from coming back as well: Study participants who kept exercising after they recovered from depression had a lower risk of relapse than those who took antidepressant medication but did not exercise.
"Those people who exercised had half the risk of being depressed of the patients in the medication-only group," says James A. Blumenthal, PhD, one of the study's authors. "This suggests that maintaining exercise is important in preventing a relapse of depressive symptoms." Blumenthal is a professor of medical psychology at Duke University Medical Center in Durham, N.C.
Particularly surprising was a finding that study participants in the exercise-only group fared better than people who continued with both exercise and medication, Blumenthal says.
But psychiatrist Ronald Onkin, MD, who reviewed the study for WebMD, says that it is "somewhat flawed from its inception" and warns that people with major depression should not use exercise as a substitute for medication.
To conduct their research, lead author Michael Babyak, PhD, and his colleagues advertised for volunteers for a study of exercise and depression. The subjects, all of whom were diagnosed with depression, were divided into three groups, and each was treated for 16 weeks. One group used aerobic exercise alone; the second was treated with the antidepressant Zoloft; and the third used a combination of exercise and medication.
The exercise consisted of thrice-weekly supervised sessions of cycling or walking in which the participants achieved 70-85% of their maximum heart rates for 30 minutes, plus a 10-minute warm-up and five-minute cool-down period.
Patients were evaluated just before they entered the study, right after they completed the four-month treatment period, and again at a six-month follow-up examination. In all, 156 patients completed the four-month treatment phase of the study.
At the end of the treatment period, the patients were encouraged to continue with some form of therapy on their own, be it exercise or medication. The rate of recovery from depression at that point was similar in all three groups, averaging about 65%.
Of the original 156 patients, 133 were available for the six-month follow up examination. The researchers found that depression had returned in only about half as many patients in the exercise-only group as in either of the other two groups. In all, about two-thirds of the people who had been assigned to the exercise-only or drugs-plus-exercise treatments kept exercising during the follow-up period. Nearly half of the people who had initially been in the drug-only group began some form of exercise program during the follow-up period.
But Onkin, an assistant clinical professor of psychiatry at the University of California in Los Angeles, has several reservations about the study, starting with the way the researchers recruited their volunteers. "You have a group of people who already have their minds made up about what's going to help them," he tells WebMD. Indeed, the study authors write that "there may have been some 'antimedication' sentiment among some of the study participants, as evidenced by expressions of disappointment when notified of their assignment to a group in which they would receive medication in addition to exercise."
Onkin points out that the people who exercised did so under supervision and in a group, three times a week, while the people in the medication-only group simply met with a psychiatrist for a few minutes every four weeks to monitor the effects of the medication. "[The authors] didn't take into account the human contact," he says. "Just going to a gym and watching other people work out is beneficial."
Also, he says, four months on medication is not enough for most people to recover completely from major depression.
Like the authors, Onkin, who was not involved in the study, expressed surprise that the people who exercised had lower rates of depression during the follow-up period than those who continued with both medication and exercise. In addition to their "anti-drug sentiment," those participants may have believed that taking a drug robbed them of some of the self-mastery they might have felt had they recovered with exercise alone, the authors write.
For Blumenthal, the most important lesson is that "exercise seems to be effective at relieving depression ... and by maintaining an exercise program, the risk of relapsing is significantly reduced."
Despite his reservations about this study, Onkin agrees that exercise plays an important role in relieving depression. "My own clinical experience is that patients who go on medication and then just sit around at home and watch television don't get any better," he says. "Even just a walk around the block or going in the garden and pulling weeds for 10 minutes" has a measurable effect.
But, he warns, it should not take the place of drug therapy: "For the average person there is no substitute for the right medication to correct the chemical imbalance in the brain."