# Isotemporal substitution from sedentary behavior or sleep to physical activity: associations with depression risk in older adults—a systematic review and meta-analysis

## TL;DR

This study finds that replacing sedentary behavior or sleep with moderate-to-vigorous physical activity is linked to lower depression risk in older adults.

## Contribution

The novel contribution is quantifying how substituting sedentary time or sleep with physical activity reduces depression risk in older populations.

## Key findings

- Replacing sedentary behavior with moderate-to-vigorous physical activity significantly reduces depression risk.
- Substituting sleep with moderate-to-vigorous physical activity also lowers depression risk marginally.
- Light physical activity does not significantly affect depression risk when replacing sedentary behavior.

## Abstract

As global population aging intensifies, mental health issues in older adults are increasingly prominent, with depression being particularly prevalent and detrimental. The study investigated how substituting sedentary behavior (SB) and sleep (SLP) with physical activity (PA) affects depression risk in this population.

Meta-analysis was conducted by searching four databases: PubMed, Scopus, SPORTdiscus, and PsycINFO (via EBSCOhost platform) for relevant studies published until January 2025. Regression coefficients (β) with 95% confidence intervals (CIs) for depressive symptoms were estimated. Publication bias was assessed using funnel plots and Egger’s tests, and heterogeneity was evaluated using Q tests and the I2 statistic. All statistical analyses were performed using STATA software (version 18.0).

Among 18,912 participants (53.45% female, ≥60 years) across nine studies, replacing SB with MVPA significantly reduced depression (β = −0.12, 95% CI: −0.20, −0.04), subgroup analyses indicated that reallocating 10, 30 and 60 min/day of SB to MVPA (β = −0.06, 95% CI = −0.19, 0.08; β = −0.14, 95% CI = −0.25, −0.02; β = −0.34, 95% CI = −0.59, −0.09), while light PA (LPA) showed no significant effect (β = −0.02, 95% CI = −0.08, 0.03). Replacing SB with SLP marginally reduced depression (β = −0.06, 95% CI = −0.10, 0.00). Substituting SLP with MVPA also lowered risk (β = −0.16, 95% CI: −0.31, −0.01).

Substituting SB and SLP with MVPA is significantly associated with a reduction in depression, whereas no significant association is observed when replaced by LPA.

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=546666, identifier CRD42024546666.