This systematic review aims to determine whether exercise timing influences different
health indicators. The search, conducted until May 2025 across PubMed, Web of Science,
EBSCO, China National Knowledge Infrastructure, and Wanfang databases, reviewed 2937
articles. This review included randomized controlled trials in English that explored
exercise timing for various populations, excluding unspecified exercise timing, animal
studies, and low-quality articles. 43 studies with 3543 participants were included.
The risk of bias was assessed using the Cochrane Risk of Bias 2 tool, and study characteristics
and results were tabulated. Current evidence suggests exercise timing may differentially
impact health dimensions: afternoon exercise may improve metabolism in metabolic disorders;
post-dinner exercise might enhance blood glucose control for type 2 diabetes; pre-meal
exercise could reduce appetite for overweight and obese individuals; evening exercise
may improve sleep quality for sleep disorders but may negatively affect early chronotypes;
morning exercise may enhance athlete performance, while afternoon exercise may promote
the recovery of ordinary individuals; morning exercise should be approached cautiously
in cardiovascular risk groups. However, contradictions in some dimensions highlight
the need for further rigorous research to solidify implications for exercise prescriptions.
The study protocol was prospectively registered on PROSPERO (ID: CRD42024595984).
