AUSTIN, Tex. Jan. 27 - Just a half hour on the treadmill was enough to provide a significant mood boost for patients with a major depressive disorder, according to a small study.
Compared with sitting quietly undisturbed for a half-hour, walking up to 70% of age-predicted maximum heart rate for 30 minutes significantly improved patients' vigor (P<0.01) and sense of well-being (P<0.01), reported John B. Bartholomew, Ph.D., of the exercise and sport psychology lab at the University of Texas here.
A walk on the treadmill and sitting quietly were both equally effective in reducing feelings of confusion, tension, anger, distress and fatigue, he and colleagues wrote in a recent issue of Medicine & Science in Sports & Exercise. However, exercise showed no greater effect on fatigue than sitting still.
The evidence suggesting exercise may help blunt some symptoms of depression, or temporarily improve them, has been growing, yet it's unknown whether exercise produces an immediate effect. There is some evidence indicating there may be a dose-response relationship between exercise and its therapeutic effects on depression.
While Dr. Bartholomew and colleagues aren't suggesting a single stroll on the treadmill or any single episode of exercise will provide lasting clinical effects against depression, a brisk walk is a cheap and easy way to get a much-needed emotional lift, they said.
"Given the debilitating symptoms of depression, a respite such as this is potentially invaluable to those who suffer with major depressive disorder," the team wrote. "This is especially true because the time course of pharmacologic treatments requires at least two to four weeks and can exceed six to eight weeks before providing significant relief of depression."
Fifteen men and 25 women diagnosed with major depressive disorder according to DMS-IV criteria were randomly assigned to either exercise or sitting quietly two weeks after their diagnosis. No other treatment occurred between the pre- and post-test evaluations.
The mean age of the participants was 38 (range 18-55); 68% of the group was white, 17% were Latino, and 11% were African American. None of the participants had any other comorbid conditions and none were told to refrain from coffee, smoking, or any other mood-altering products, such as energy drinks, chocolate, or dietary supplements.
The testing for both groups occurred in the same room. Those assigned to sit quietly were provided a comfortable non-reclining chair located in the same room as the treadmill. They were not allowed to sleep or read during this time. Both the resting patients and the exercising patients did not interact with anyone else during their assigned half hour.
All of the patients filled out questionnaires about their mood five minutes prior to either sitting or walking. Then after the half-hour, they completed questionnaires at five, 30, and 60 minutes.
The differences in scores measuring feelings of well-being were most pronounced between the two groups five minutes and 30 minutes after their assignments had ended (d=1.13, and d=1.06, respectively), indicating a sense of well-being persisted for the exercise group even a half hour after exercise had ended. Those who rested quietly showed no change.
The same was true for vigor between the two groups (d=1.02 at five minutes and d=0.73 at 30 minutes), Dr. Bartholomew and his colleagues reported.
The effects appeared to have tapered off by 60 minutes.
Interestingly, exercise proved no different than sitting quietly in improving fatigue. The authors said earlier research has produced varying results on the association between aerobic exercise and fatigue associated with depression.
The results may be due to biochemical changes that occur during exercise or it may also be related to a sense of achievement that comes with the successful completion of an activity, or both, the authors said.
The investigators noted some limitations to their study. The severity of the patients' symptoms was not examined, so that might be a possible moderating factor.
However, the findings are promising enough to warrant further study, the researchers wrote, "to determine the limits of acute exercise to provide this short-term benefit."