Associations of exercise procrastination and exercise addiction with mental well-being.

Exercise procrastination and exercise addiction reflect maladaptive patterns that may be linked to mental well-being, yet their dose-response relationships and potential mechanisms remain unclear. We conducted a cross-sectional survey among 570 Chinese university students (mean age = 19.15 ± 1.09 years; 52.3% men). Exercise procrastination was assessed using the Procrastination in Exercise Scale (PES), exercise addiction using the Revised Exercise Addiction Inventory (EAI-R), physical activity using the Physical Activity Rating Scale (PARS-3), and mental well-being using the WHO-5 Well-Being Index. Pearson correlations were used to describe bivariate associations. Restricted cubic spline (RCS) models were applied to examine potential non-linear associations between exercise procrastination/addiction and mental well-being. Mediation analyses were conducted as a theory-informed secondary analysis to examine whether physical activity might represent a potential pathway linking these associations. We found that exercise addiction was negatively correlated with mental well-being, while exercise procrastination was positively correlated with mental well-being. RCS analyses indicated a significant association between exercise addiction and mental well-being with weak evidence of non-linearity. For exercise procrastination, the association with mental well-being showed an inverted U-shaped pattern. In mediation models, physical activity did not significantly mediate the associations between exercise addiction/procrastination and mental well-being. In conclusion, exercise addiction and exercise procrastination show distinct patterns of association with mental well-being, and these relationships were not explained by physical activity in this sample. Future research should further clarify alternative psychological or contextual pathways linking these exercise-related behaviors to mental well-being.