Exercise has been shown to be comparable in remission rate and adherence rate to anti-depressant medication. However, exercise does not have the social stigma that prevents many from seeking anti-depressant medication.
Mild to moderate major depressive disorder (MDD) is a serious illness that affects many Americans. According to the Global Burden of Disease, MDD ranks second globally, only behind heart disease, in responsibility for years of life lost due to disability or premature death. According to a 1999 report from the US Surgeon General, only 23% of people inflicted with MDD seek treatment. Unfortunately, the social stigma around depression, and psychological problems in general, prevents many people from seeking treatment. This stigma is a major hurdle to getting proven pharmaceutical anti-depressant treatments out to those who need them. A small, carefully controlled study found that exercise, an activity viewed positively by society, may work as well as anti-depressant pharmaceuticals and better than cognitive therapy in curing mild to moderate major depressive disorder (Exercise treatment for depression: Efficacy and dose response, 2004).
The study, published in 2005 in the American Journal of Preventive Medicine, divided study participants with MDD into 4 experimental groups and a control group. The experimental group was separated by dosage of exercise and frequency by which that dosage was administered. The exercise dosages were the public health recommended 17.5 Cal/kg/week and a low dosage of exercise at 7.0 Cal/kg/week. The frequency by which these dosages were administered was 3 times a week and 5 times a week. The control group participated in flexibility exercise 3 days a week.
Interestingly, the frequency of exercise per a week did not affect the success of the treatment. However, dosage of exercise did. Although the public health recommended dosage of 17.5 Cal/kg/week had a success rate (47% reduction in 17-item Hamilton Rating Scale for Depression-HRSD) comparable to pharmaceutical anti-depressants, the low exercise dosage of 7.0 Cal/kg/week resulted in a success rate (30% HRSD reduction) only slightly better than the placebo (29% HRSD reduction). The results of the different dosages are shown in the figure below.
The study administered exercise dosage in a clinically controlled, individual setting to ensure validity of dosage and exclude social benefits of exercising with others. The treatments were administered for 12 weeks.
Remission rate of depression symptoms by the public health recommended exercise dose was 42%. This compares to a 42% remission rate of anti-depressant medication imipramine hydrochloride and a 36% rate of remission for cognitive behavioral therapy (R.R. Pate, M. Pratt, S.N. Blair et al. Physical activity and public health. 1995). In addition, exercise treatment has been criticized for treatment adherence. However, in this study the exercise treatment adherence (72%) compares favorably to adherence rates found in medication trials.
In summary, the public health recommended dosage of exercise treats depression as well as anti-depressant medication. However, low dosage of exercise did little better than the placebo control group. Frequency did not affect the results. Adherence rate was comparable to medication trials suggesting it could provide a viable, stigma-free alternate treatment. This study was small by many standards, 80 participants, but more research should be done to explore the alternate treatment of mild or moderate major depression disorder with exercise.