Why this study matters

Physical activity, even at one-half the public health recommended amount, will reduce the risk of depression, thus preventing up to 1 in 9 cases of depression.

Study design

PubMed, SCOPUS, Web of Science, PsycINFO, and the reference lists of systematic reviews were searched for prospective studies involving physical activity and risk estimates for depression.

Results and conclusion

This review included 15 studies, 190,131 participants, and 2,110,588 person-years of relevant data.

An inverse curvilinear association was demonstrated between physical activity and risk of depression. Participants who engaged in minimal exercise were at the greatest risk for depression. Specifically, adults who achieved the full and one-half of the recommended marginal metabolic equivalent task (mMET) hours each week, had a 25% and 18% lower risk of depression, respectively.

It was estimated that if all of the participants met the recommended mMET hours each week, 11.5% of depression cases would have been averted.