Initiation, Maintenance, and Discontinuation of Habitual Exercise and Perceived Sleep Restfulness: A Population-Based Cohort Study

PURPOSE: Sleep restfulness is a simple yet meaningful indicator of sleep health. Although physical activity is known to influence sleep, it remains unclear how initiating, maintaining, and discontinuing physical activity affect sleep restfulness. METHODS: We analyzed longitudinal data from 702,007 Japanese adults who underwent annual health checkups in 2021 and 2022. Participants with prior diagnoses of sleep disorders or with sufficient sleep restfulness at baseline were excluded. Sleep restfulness and physical activity were assessed using a standardized self-administered questionnaire as part of the health checkups. Physical activity was examined in two domains: daily physical activity and regular exercise. Odds ratios (ORs) and 95% confidence intervals (CIs) for improvements in sleep restfulness were calculated according to the initiation, maintenance, and discontinuation of physical activity. RESULTS: Regular exercise showed consistent associations across initiation (adjusted OR [95% CI], 1.37 [1.34-1.40]), maintenance (1.23 [1.21-1.25]), and discontinuation (0.94 [0.92-0.97]). In contrast, daily physical activity did not show consistent associations in initiation (1.24 [1.22-1.26]), maintenance (1.00 [0.99-1.01]), and discontinuation (1.07 [1.05-1.09]). CONCLUSIONS: This large-scale epidemiological study demonstrates that regular exercise is strongly associated with enhanced perceived sleep restfulness. The findings suggest that initiating regular exercise may contribute to improved sleep restfulness and that maintaining an exercise habit may help enhance perceived sleep restfulness even among individuals who already exercise regularly but feel insufficient restfulness.