Physical exercise and social avoidance and distress among college students: a cross-sectional examination of the chain mediating role of body image and psychological capital

Background Social avoidance and distress (SAD) impairs interpersonal functioning among university students, yet the pathways through which modifiable health behaviors are associated with SAD remain poorly specified. Prior work has treated the two mainly as parallel mediators, leaving open whether they operate in sequence. This study tested whether the two are ordered sequentially in their indirect association with SAD. Methods A cross-sectional sample of 671 Chinese undergraduates completed the Physical Activity Rating Scale-3, the Social Avoidance and Distress Scale, the Body Appreciation Scale-2 and the Psychological Capital Questionnaire-24. Measurement validity was established by confirmatory factor analysis before the mediation analysis, which used PROCESS Model 6 with 5,000 bias-corrected bootstrap resamples and a mediator ordering specified in advance on theoretical grounds. Results Physical exercise was positively associated with body image (β = 0.12) and psychological capital (β = 0.11), and negatively with SAD (r = −0.15). The serial indirect pathway through body image and then psychological capital was significant (−0.014, 95% CI [−0.026, −0.003]), accounting for 9.3% of the total association. Conclusion Physical exercise was associated with lower SAD, and this association was statistically consistent with an indirect pathway through more positive body image and, in turn, greater psychological capital. These findings delineate a sequential psychological pathway linking physical exercise to social functioning and identify two modifiable targets for physical education and mental-health services in higher education.