Can exercise truly alleviate mild-to-moderate and subthreshold depression? Evidence from randomized controlled trials

This study centers on populations with mild-to-moderate and subthreshold depression, excluding pharmacological interference, to systematically evaluate the comparative efficacy of various exercise modalities.

Adhering to PRISMA guidelines, a systematic search was conducted across PubMed, Embase, Web of Science, the Cochrane Library, and PsycINFO databases up to January 25, 2026. Inclusion criteria encompassed randomized controlled trials (RCTs) implementing structured exercise interventions for mild-to-moderate and subthreshold depression. A random-effects model was utilized to calculate the pooled effect size (Hedges' g). Subgroup analyses were performed to explore the moderating effects of exercise type. Methodological quality was evaluated using the Cochrane RoB 2.0 tool.

A total of 37 RCTs (3,110 unique participants) were included, contributing 3,922 observations across multiple comparisons. The analysis revealed that exercise interventions significantly ameliorated symptoms of non-severe depression compared to control groups, yielding a large pooled effect size (Hedges' g = -0.86, 95% CI [-1.06, -0.68], p < 0.001). High overall heterogeneity was observed (I ² = 82.0%). Subgroup analysis indicated differences in efficacy across exercise types: aerobic exercises (g = -0.91) and mind-body exercises (g = -0.88) demonstrated the strongest improvement effects; resistance training (g = -0.84) followed; and mixed/other exercises showed a moderate effect size (g = -0.64). Notably, mind-body exercises exhibited the lowest relative heterogeneity (I ² = 54%), suggesting superior therapeutic stability. Egger's test indicated potential publication bias (p < 0.05).

Physical exercise serves as an effective intervention for ameliorating non-severe depression. Among exercise modalities, aerobic exercise demonstrated the most substantial symptom alleviation effects, while mind-body exercises exhibited optimal therapeutic stability. However, the overall certainty of evidence is rated as 'Low' (GRADE), and the presence of potential publication bias necessitates a cautious interpretation of the exact effect size magnitude. Clinicians are encouraged to integrate structured exercise as a valuable adjunctive strategy for non-severe depression management.