Toward a Mediated Model of Physical Activity in Relation to Psychological Distress

Leisure-time physical activity has well demonstrated benefits in mitigating symptoms of depression and, to a lesser extent, anxiety. A variety of theoretical mechanisms have been proposed as mediators of this linkage. There has been no reported attempt to develop a unified model of the relative contributions of the proposed mechanisms. To begin to fill this gap, 394 first-year university students were surveyed concerning their participation in physical activity (broadly defined), their level of depressive and anxiety symptoms as indexed by the Kessler 10, and four mediators identified as promising candidates in the literature: behavioral activation (sense of purpose and achievement), belonging (sense of social contact and inclusion), sense of flow (concentrated engagement in activity), and coaching relationship (formal or informal assistance from another person). Each of the candidate mechanisms individually mediated the relationship between physical activity and the K10 score. However, the scores for each of the mechanisms themselves were inter-correlated to a small or medium degree. When all scores were analysed as an integrated model, only behavioral activation and belonging were significant mediators. Once these two mediators had been accounted for, there was no additional direct effect of physical activity on both depression and anxiety. The next steps for refining and testing the model are discussed.