Aerobic exercise is effective for mild to moderate depression

Question Is aerobic exercise effective in treating mild to moderate depression?

Synopsis Exercise may be an effective treatment for adults with major depressive disorder. The investigators randomly assigned (concealed allocation assignment) 80 adults, aged 20 to 45 years, with mild to moderate depression, to one of five exercise treatment groups: 7.0 kcal/kg/week (low dose) performed in either three or five sessions per week; 17.5 kcal/kg/week (high dose) performed in either three or five sessions per week; or a flexibility exercise only (control) three days per week. The high dose is consistent with public health recommendations for physical activity. Outcomes were assessed by individuals blinded to treatment group assignment. Of the 80 randomised participants, 10 (13%) were lost to follow-up at 12 weeks. Using intention to treat analysis, patients assigned to either of the high dose exercise groups were significantly more likely to have a clinically relevant response (defined as a 50% or more reduction in mean scores from baseline on the Hamilton rating scale for depression) than those in the control group (42% v 23%; number needed to treat (NNT) = 5). There were no significant differences between the three and five sessions per week high dose exercise groups. Patients in the three sessions per week low dose exercise group were also more likely to have a significant response than the control group (38% v 23%; NNT = 7), but there was no significant difference between the five sessions per week low dose group and the control group. The combined high dose exercise group was not significantly more effective than the combined low dose exercise group.

Bottom line Both high dose and low dose aerobic exercise are somewhat effective in treating mild to moderate depression. Exercising three times a week is at least as effective as five times a week. To give a real world example of “high dose” exercise, a 70 kg man exercising to a heart rate of 145 beats per minute for 30 minutes on a treadmill expends about 350 kcal per session, requiring a total of three sessions per week. A previous study of walking or jogging at 70% to 80% of maximal aerobic intensity was also as effective as drug therapy in treating mild depression (Blumental JA et al. Arch Intern Med 1999;159: 2349-56).

Level of evidence 1b (see www.infopoems.com/levels.html). Individual randomised controlled trials (with narrow confidence interval).