Exercise for the Treatment of Depression

Depression is a common mental disorder that presents with depressed mood, loss of interest or pleasure, feel- ings of guilt or low self-worth, disturbed sleep and/or appetite, low energy, and poor concentration. Depression is a wide- spread and often chronic condition. Lifetime prevalence estimates for major depressive disorder are approximately 15% to 20%; 1-year prevalence estimates are 5% to 10%. Moreover, depression is characterized by high rates of relapse: 22% to 50% of patients suffer recurrent episodes within 6 months after recovery. Depression is associated with a high incidence of co-morbid somatic illness. Individuals suffering from major depression run a higher relative risk of coronary heart disease, type 2 diabetes and osteoporosis compared with the general popula- tion. In general, depressed individuals exhibit a less active life-style and have a reduced cardio-respiratory fitness in com- parison with the general population. Strong evidence demonstrates that lack of physical activity is associated with an un- healthier body mass and composition, and a biomarker risk profile for cardiovascular disease, type 2 diabetes, and osteo- porosis. A growing body of evidence suggests that exercise is an effective treatment for depression. For mild to moderate depression the effect of exercise may be comparable to antidepressant medication and psychotherapy; for severe depres- sion exercise seems to be a valuable complementary therapy to the traditional treatments. Exercise training not only im- proves depression, but also produces 'positive side effects' on depression associated physical diseases and cognitive de- cline. We identified the meta-analyses in the area of exer- cise/physical activity and depression from 1998 until 2008. Relevant studies were identified by searching PubMed, Med- line, Sport Discus, and PsycInfo. Terms used in the search were 'depression', 'clinical depression', 'depressive symp- toms', 'exercise', 'physical activity', 'meta-analysis'. We also identified the meta-analyses and single-studies on the theme depression as an independent risk factor for develop- ment of coronary heart disease, type 2 diabetes and osteopo- rosis. All studies that investigated the role of exercise in the association among depression and these diseases were in- cluded. Finally, literature was also identified by citation tracking using reference lists from selected papers.