A Medical Center study recently showed that continued exercise greatly reduces the chances of depression relapse in depressed patients.
The research, which was funded by a National Institutes of Health grant, was a continuation of a previous study that reported exercise was as effective as taking anti-depressants in reducing depression among patients.
The most recent study, which followed the same patients from the initial trial published last summer, found that individuals who were treated with exercise were less likely to relapse six months after treatment than those who were prescribed medication.
Of the whole test population, 38 percent of the drug-only group and 31 percent of the exercise-plus-drug group relapsed, compared to only 8 percent of exercise-only patients. These results were reported in the October issue of Psychosomatic Medicine.
"The importance of the follow-up study is that the maintenance of exercise over time may be important in maintaining the benefits achieved over time," said Dr. James Blumenthal, lead researcher and Duke professor of psychiatry.
The research is also significant in its broad applicability. "I see no reason why these results wouldn't be generalizable to adults younger than the ones tested," Blumenthal said.
Others predicted changes in treating depression as well.
"[These findings] suggest that physicians with this kind of information available will recommend an exercise program as viable treatment in addition to cognitive therapy and medication," said Dr. Edward Craighead, co-researcher and director of the Clinical Doctoral Program at the University of Colorado at Boulder.
However, many unknowns remain about the causal mechanism of exercise's benefits.
"There are interesting questions about the ways through which psychological interventions work." said Craighead. "We have to find out if changes in the brain [caused by exercise] are the same as changes caused by drugs."
The researchers are planning a larger trial that involves 216 clinically depressed individuals over age 55. One important difference is that, unlike its predecessor, this future trial will focus on determining the cause behind the observed positive effect of exercise on depressed patients.
"In the first study, participants exercised in a group; therefore, we don't know if they benefited from the direct physiological effects of exercise, from the social interaction or from the combination," said Dr. Alisha Hart, research coordinator for the new study and an instructor in psychology and behavioral science.
The new phase of the trial will help in further examining this possible group effect by randomly assigning patients to either a home-based exercise regimen, medication, a pill placebo or supervised group exercise in the Duke Center for Living.
Exercising patients will be doing a brisk walking program that is individually tailored to help each person reach 70 percent of his targeted heart rate. The patients will exercise for 45 minutes three times a week for four months. They will be assessed immediately after treatment and again six and twelve months after the trial.
One concern, though, is that much of the exercise is self-reported. However, Hart is confident this will not be a major problem.
"Although patients exercising at home could lie about their level of exercise, the detailed weekly reports that we require are designed to minimize the likelihood of this," said Hart. "In addition, the treadmill test that patients will perform pre- and post-treatment will provide an objective measure of increased cardiovascular fitness."
Marko Djuranovic contributed to this story.
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