Association between perceived greenness and physical exercise among university students: nature connectedness as a statistical mediator and gender as a moderator

Abstract

Background Supportive residential environments and regular physical exercise may serve as upstream resources for health promotion among university students. However, whether perceived greenness is associated with exercise through nature connectedness, and whether this pattern differs by gender, remains unclear. Methods We analyzed cross-sectional data from 3,418 university students in China in the cleaned EPOCH-A dataset. Perceived greenness of the longest-lived residential environment was assessed using neighborhood and window-view greenness items. Nature connectedness was measured using the single-item Inclusion of Nature in Self scale, and physical exercise during the previous month using the Physical Activity Rating Scale-3. Adjusting for age, subjective socioeconomic status, grade, and residential setting, we estimated a conditional process model equivalent to PROCESS Model 14, using HC3 robust standard errors and 5,000 bootstrap resamples. Results Perceived greenness was positively correlated with nature connectedness (r = 0.288, p < 0.001) and physical exercise (r = 0.068, p < 0.001), while nature connectedness was positively correlated with exercise (r = 0.131, p < 0.001). After covariate adjustment, perceived greenness was positively associated with nature connectedness (B = 0.241, 95% CI 0.211–0.271). The nature connectedness-by-gender interaction was significant (B = −1.953, 95% CI −2.885 to −1.022), with a stronger nature connectedness–exercise association in men (B = 2.614) than women (B = 0.660). The conditional indirect association of perceived greenness with exercise through nature connectedness was 0.630 (95% bootstrap CI 0.424–0.853) in men and 0.159 (95% bootstrap CI 0.052–0.270) in women. The index of moderated mediation was −0.471 (95% bootstrap CI −0.705 to −0.251). Findings were directionally consistent across alternative continuous exercise measures. Conclusions Perceived greenness, nature connectedness, and physical exercise showed modest but consistent concurrent associations, with a stronger nature connectedness–exercise association in men. Because the study was cross-sectional and exposure and outcome had different temporal reference frames, causal mediation or temporal ordering cannot be established.