Better together: How group-based physical activity protects against depression.

Against the backdrop of evidence that physical activity can protect against depression, there has been growing interest in the mechanisms through which this relationship operates (e.g., biological adaptations), and the factors that might moderate it (e.g., physical activity intensity). However, no attempt has been made to examine whether, or through what mechanisms, depression-related benefits might arise from belonging to groups that engage in physical activity. Across two studies, we addressed these shortcomings by (a) examining whether engaging in physical activity specifically in the context of sport or exercise groups protects against depression and (b) testing two pathways through which benefits might arise: greater physical activity and reduced loneliness. Study 1 (N = 4549) used data from three waves of a population study of older adults residing in England. Sport or exercise group membership predicted fewer depression symptoms four years later. This relationship was underpinned by sport or exercise group members engaging in physical activity more frequently and feeling less lonely. Clinical depression rates were almost twice as high among non-group members than group members. Study 2 (N = 635) included Australian adults who were members of sport and exercise groups, recruited during the enforced suspension of all group-based sport and exercise due to COVID-19 restrictions. The more sport or exercise groups participants had lost physical access to, the more severe their depression symptoms. Clinical depression rates were over twice as high among those who had lost access to >2 groups compared to those who had lost access to <2 groups. The relationship between number of groups lost and depression symptom severity was mediated by greater loneliness, but not by overall physical activity. Overall, findings suggest that belonging to groups that engage in physical activity can protect against depression, and point to the value of initiatives that aim to promote people's engagement in such groups.