Sedentary behavior, body image, physical activity enjoyment, and life satisfaction: a three-wave longitudinal study among college students

Abstract

Excessive sedentary behavior is a modifiable public health concern in university populations, and life satisfaction is an important indicator of psychological wellbeing and a relevant target for campus health promotion. This study examined the longitudinal association between sedentary behavior and life satisfaction and tested whether body image and physical activity enjoyment operated as parallel psychological mediators. A three-wave longitudinal survey was conducted among college students in Zhejiang Province, China, at six-month intervals. The analytic sample comprised 426 participants with complete matched data across all three waves. The measurement model represented body image (BI) and physical activity enjoyment (PACES) with four item parcels each and life satisfaction (SWLS) with its five individual items. Longitudinal mediation controlled both T2 and T1 SWLS, and a fully reciprocal manifest-score cross-lagged panel model (CLPM) together with a full-forward lag-2 robustness model was estimated. T1 sedentary behavior negatively predicted T2 body image (β = – 0.227, p < 0.001) and physical activity enjoyment (β = – 0.248, p < 0.001). After adjustment for T2 and T1 life satisfaction, T2 body image (β = 0.151, p < 0.001) and physical activity enjoyment (β = 0.220, p < 0.001) independently predicted T3 life satisfaction. Bias-corrected bootstrap analyses showed significant indirect effects through body image [ b = – 0.150, 95% CI ( – 0.247, – 0.079)] and physical activity enjoyment [ b = −0.237, 95% CI (−0.368, −0.141)]; their difference was not significant. The fully reciprocal manifest-score CLPM showed acceptable overall fit (χ 2 = 45.397, df = 16, CFI = 0.989, TLI = 0.954, RMSEA = 0.066, SRMR = 0.020). Sedentary behavior was longitudinally associated with lower life satisfaction among college students through both body-related self-evaluation and exercise-related affective experience. From a public health and health-promotion perspective, the findings identify prolonged sitting as a potentially modifiable behavioral target and support integrated campus strategies that combine sedentary-time reduction, positive body-image promotion, and enjoyable physical activity opportunities to support student wellbeing.