# Effects of exercise interventions on memory in depression: a three-level meta-analysis

## TL;DR

This study finds that exercise may slightly improve verbal memory in people with depression, but the effect is small and inconsistent.

## Contribution

The paper introduces a three-level meta-analysis to evaluate the impact of exercise on memory in depression patients.

## Key findings

- Exercise had a small, statistically significant effect on verbal memory (g = 0.17).
- Low-to-moderate intensity mind-body exercise was most effective for verbal memory improvement.
- No clear effect of exercise on visual memory was observed.

## Abstract

Patients with depression have memory impairment. Exercise can improve memory in people with depression. This study employs a three-level meta-analysis to investigate the interventional effects of exercise on verbal and visual memory in patients with depression.

A systematic electronic search was conducted in China National Knowledge Infrastructure, Wanfang Data, China Biomedicine, PubMed, EMBASE, the Cochrane Library, and Web of Science to identify randomized controlled trials investigating the effects of exercise interventions on memory in individuals with depression, up to July 18, 2024. A three-level meta-analysis based on a random-effects model was performed using R. The risk of bias of the included studies was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool.

A total of 16 studies were included in the analysis. The results indicated a statistically significant but small effect of exercise on verbal memory in patients with depression (g = 0.17, 95% confidence interval (CI) [0.02–0.32], p = 0.03); however, the 95% prediction interval crossed zero, suggesting that the effect may not be consistent across different settings or future studies; however, the 95% prediction interval crossed zero, suggesting that the effect may not be consistent across different settings or future studies (g = 0.27, 95% CI [−0.00–0.54], p = 0.05). Exercise intensity significantly moderated the effect of exercise on verbal memory in patients with depression (F = 3.39, p = 0.04), whereas exercise type, session time, duration, age, and intervention content of the experimental group were not moderating factors (p > 0.05). Low-to-moderate intensity (g = 0.43, p < 0.01), duration ≤12 weeks (g = 0.27, p < 0.01), and session time ≤60 minutes (g = 0.18, p = 0.03) of mind-body exercise (g = 0.43, p < 0.01) were most likely to improve verbal memory in patients with depression. The level of evidence was “moderate”.

Exercise may confer a small improvement in verbal memory among adults with depression, while no clear effect was observed for visual memory. However, further randomized controlled trials are needed to explore the impact of exercise on memory in patients with depression. Research plan was registered in international system evaluation platform PROSPERO (https://www.crd.york.ac.uk/PROSPERO/) (CRD42023473393).