Xiang Li, Jing Yang, Hao Gou, Chang Zhen Hu
Background With the ongoing deepening of population aging in China, the psychological well-being of older adults people has become an important indicator for measuring social health development. Physical activity, as an interventionable health behavior, has a complex relationship with psychological well-being. However, the dynamic interaction mechanisms between the two have not been systematically revealed. Methods This study employed a longitudinal design, tracking 967 older adults individuals from Guiyang and Duyun in Guizhou Province and Nanchang in Jiangxi Province between February and April 2024 (T1) and February and April 2025 (T2). Using cross-lagged panel network analysis (CLPN), which integrates both cross-sectional and longitudinal network models, we examined the temporal predictive relationships between physical activity and the multidimensional aspects of psychological well-being. Results (1) The network connection density between physical activity and psychological well-being increased from 56.84% at T1 to 60.00% at T2, indicating a continuous enhancement of system associations; (2) The cross-sectional network revealed that the core association shifted from “personal growth—openness” ( r = 0.488) to “autonomous value—self-assurance” ( r = 0.393); (3) The cross-lagged network demonstrated that physical activity has a predictive effect on psychological well-being, with the frequency of exercise significantly predicting autonomous values (β = 0.166); (4) “Meaning in life” plays both a driving and bridging role in the system and is a key target for interventions. Conclusion Physical activity and psychological well-being in older adults individuals constitute a dynamic, bidirectional promoting system, with the path of influence evolving in stages from social support to personal growth. The findings provide a theoretical basis and practical guidance for developing staged and precise health promotion programs for the older adults.