Background Accumulating evidence indicates that face-to-face physical activity interventions improve the physical and mental health of people with mental disorders. However, it is unclear whether internet-delivered physical activity interventions are also efficacious. Objective Our aim was to determine the effect of online physical activity interventions on the severity of symptoms of mental illness among people experiencing mental disorders. Methods A systematic review of major electronic databases was conducted from inception to January 2015. Randomised controlled trials of internet-delivered interventions to increase physical activity participation in adults (>18years) with a DSM, ICD, clinician-confirmed diagnosis, and/or those receiving specialist mental health treatment were eligible for inclusion. Outcome data for symptom severity (depression) and physical activity participation was extracted. Results Two trials (N =95 participants) met the inclusion criteria, which investigated online clinician-guided interventions of 9–10week duration. Results were discrepant across studies. One study found a moderate between-groups effect size compared to wait-list control on depression outcomes (d =.67) but no differences in physical activity participation. In the other study, there were no significant differences between an online physical activity intervention versus treatment-as-usual in a university counselling service. Conclusion The preliminary findings suggest that online physical activity interventions may have positive effects on depression symptoms, but the size of the effects and mechanism of change remain unclear. Further research is critically needed to explore the efficacy and acceptability of online physical interventions for people with mental disorders. 
Online physical activity interventions for mental disorders: A systematic review