Effects of physical activity on depressive symptoms in middle-aged and younger-old adults: a systematic review and meta-analysis

BackgroundDepression is a common mental health issue in middle-aged and younger-old adults. It can substantially impair their well-being and daily functioning. Physical activity is often recommended to help with depression, but its effectiveness for middle-aged and younger-old adults is not clear. The most effective exercise prescription also remains to be determined. This systematic review aims to answer two questions: Does physical activity reduce depressive symptoms in this group? And if so, which workout parameters work better?MethodsPubMed, CNKI, Wanfang Data, Embase, VIP, and the Cochrane Library were searched for randomized controlled trials (RCTs) to examine the impact of physical activity on this population. The search timeframe was based on the introduction of databases up to May 15, 2025. The risk of bias was assessed in each included study using the Cochrane Handbook. All meta-analyses were conducted with Review Manager 5.4.ResultsSeven studies (9 RCTs, 494 participants) were included. Physical activity reduced depressive symptoms in medication-free participants. However, in the few studies that examined exercise as an adjunct to stable antidepressant treatment, no additional benefit was observed. In subgroup analyses, Tai Chi was associated with an effect estimate that differed from those of walking or running. Interventions with total duration >6 months, session length ≥60 min, and frequency ≥3 times per week showed greater reductions in depressive symptoms compared with those below these thresholds.ConclusionBecause all subgroup comparisons were indirect and no direct head-to-head trials were included, no conclusion about the superiority of any exercise type or specific dose parameter can be drawn. Preliminary evidence suggests that for medication-free participants, long-term Tai Chi practice (≥3 times/week, >60 min/session, ≥6 months) was associated with a greater reduction in depressive symptoms in exploratory subgroup analyses. Given the high heterogeneity and other methodological limitations noted, further research with larger samples and more rigorous designs is required before definitive conclusions can be drawn.Systematic review registrationhttps://www.crd.york.ac.uk/PROSPERO/view/CRD420251125076, identifier CRD420251125076.