The effects of exercise on episodic memory in patients with depression: a three-level meta-analysis

Using a three-level meta-analysis approach, this study evaluated the effects of exercise on episodic memory in patients with depression and explored its moderating variables.

A systematic search was conducted across seven databases to identify randomized controlled trials examining the effects of exercise interventions on episodic memory in patients with depression. Two researchers independently screened studies, extracted data, and assessed the risk of bias. A three-level meta-analysis was performed to calculate the pooled effect size (Hedges' g), and subgroup analyses were conducted to explore moderating variables.

A total of 13 randomized controlled trials (1098 participants) were included. Exercise showed a significant small-to-moderate positive effect on episodic memory in patients with depression (g = 0.210, 95% CI [0.10, 0.32]). Descriptively, significant improvements were observed for delayed recall (g = 0.213) and immediate recall (g = 0.206), whereas the effect for total learning was not significant (g = 0.243). No significant differences were found across memory indicators or exercise characteristics (all ps > 0.05). Sensitivity analyses confirmed the robustness of the findings, and the certainty of evidence was rated as moderate.

Exercise may provide small-to-moderate benefits for the episodic memory of patients with depression. No significant differences were observed among different memory indices or exercise characteristics, suggesting that these benefits are generally consistent under the conditions studied. Future research should standardize the assessment of episodic memory, extend the follow-up period, and further determine the optimal exercise prescriptions and its underlying mechanisms.