SAN FRANCISCO -- Preliminary results from a major study on depression suggest that short but strenous workouts -- as little as 8 minutes at a time -- can temporarily but dramatically reduce symptoms of depression, a Duke researcher has found.
The results are the first to demonstrate that acute physical activity, not just sustained and regular exercise, may decrease feelings of depression, tension, anger, confusion and fatigue, according to Kathleen Moore, a health psychologist in the department of psychiatry and behavioral sciences at the Duke University Medical Center.
"A number of earlier studies have shown that sustained exercise programs lower depressive symptoms in normal people," Moore said. "But the Duke study is the first to test the benefits of acute exercise on a group of people actually diagnosed with clinical depression."
Results of the study, funded by the National Institutes of Mental Health, were prepared for presentation Thursday (April 17) at the Society of Behavioral Medicine meeting.
The study involved 55 participants over the age of 50. Participants completed the Profile of Mood Survey (POMS) before exercising in order to assess their baseline mood and then walked on a treadmill for up to 14 minutes at maximum effort. After the treadmill test, they completed the 60-item questionnaire again.
Overall, the study found that participants experienced an 82 percent reduction in feelings of depression, tension, fatigue, anger and confusion. The severity of their depression -- mild, moderate or severe -- did not influence the level of improvement they felt after the test.
Moreover, participants said they felt increased vigor after the test; 82 percent of participants reported feeling more vigorous and only 18 percent reported feeling less vigorous.
"We had them exercise to the point of exhaustion, but at the end of the test, they felt more energetic and vigorous," Moore said.
Although the study will continue through July, the preliminary results are significant because they suggest an alternative or an adjunct therapy for treating depression, Moore said.
"This is particularly important for older adults who may want to limit the number of medications they take to control a multitude of medical problems," Moore said.
However, Moore cautioned that further studies will be needed to confirm the beneficial effect of acute exercise on depression, since the present study did not control for other factors -- such as social support from the exercise technician or feelings of accomplishment from mastering the exercise test -- that could have reduced depressive symptoms.
The current study is a subset of a larger, five-year study comparing the benefits of three treatments for depression: a four-month exercise program, drug therapy, or a combination of exercise and medication.