A double-edged sword: unpacking the functional heterogeneity of mobile social media use and its differential associations with exercise identity and social-media-specific sedentary time among older adults

Background As digital life prevails among older adults, this study investigates how mobile social media functions affect their exercise identity and social-media-specific sedentary time. Methods Using the S-O-R framework, a dual-path model was tested with SEM (AMOS 20.0) on data from 452 older adults in China. Results Overall, mobile social media functions were not significantly associated with exercise identity or social-media-specific sedentary time. However, specific functions showed divergent effects: information retrieval ( Z = 6.06, 95% CI [0.14, 0.27]), online guidance ( Z = 3.32, 95% CI [0.08, 0.57]), and social comparison ( Z = 2.44, 95% CI [0.05, 0.30]) positively predicted exercise identity, whereas video media and personalized algorithms negatively predicted exercise identity ( Z = -1.32, 95% CI [−0.57, −0.04]) and positively predicted social-media-specific sedentary time ( Z = 2.42, 95% CI [0.17, 1.01]). Perceived value mediated the effects of attention and interaction ( Z = 2.56, 95% CI [0.009, 0.05]) and recording ( Z = 3.30, 95% CI [0.03, 0.12]) on exercise identity. Immersive experience mediated the effect of video media and personalized algorithms on social-media-specific sedentary time ( Z = 1.41, 95% CI [0.006, 0.19]). Conclusion Mobile social media exerts dual effects on older adults’ exercise identity. Video media and personalized algorithms are key risk factors for social-media-specific sedentary time, while perceived value and immersive experience mediate distinct pathways.