Exploring the role of physical exercise on well-being among Chinese older adults: The mediating effect of sleep quality and the moderating role of social capital

Abstract

Background

Physical exercise enhances mental health, but mechanisms linking it to well-being in older adults, particularly through mediating and moderating factors, remain underexplored.

Objective

This study aimed to investigate the direct relationship between physical exercise and subjective well-being in older adults, and to test a hypothesized moderated mediation model in which sleep quality mediates the relationship, and social capital moderates the first stage of this mediation (i.e., the path from physical exercise to sleep quality).

Methods

First, descriptive statistics and Pearson correlation analyses were conducted to examine the basic associations among the main variables: physical exercise frequency, well-being (WB), sleep quality, and social capital. Subsequently, to test the hypothesized relationships, Hayes’ PROCESS macro (Model 7) was employed. This model specifically tested whether the indirect effect of exercise on well-being through sleep quality was conditional on social capital, posited as a moderator of the exercise-sleep relationship.

Results

Contrary to assumptions, physical exercise had a slight negative direct effect on well-being (b = -0.007, p = 0.020). However, sleep quality acted as a significant mediator. Crucially, social capital positively moderated the relationship between exercise and sleep quality (interaction b = 0.007, p = 0.014), supporting the first-stage moderated mediation model. Consequently, the indirect effect of exercise on well-being through sleep was significant only at higher levels of social capital (Johnson-Neyman threshold: SOC > 3.878). Thus, social interactions amplified exercise's positive impact on sleep quality, which in turn enhanced well-being.

Conclusion

Our findings challenge linear assumptions about exercise and well-being, highlighting context-dependent pathways where the psychological benefits of exercise are fully realized only when supported by adequate social capital, which strengthens the link between exercise and improved sleep. Culturally tailored interventions that integrate socially embedded physical activities and sleep hygiene practices could optimize holistic well-being in collectivist societies. Public health strategies should prioritize group-based exercises and community support networks. Longitudinal research is needed to validate these dynamics and inform effective ageing policies.