Digital engagement and physical activity patterns across Chinese populations: a secondary analysis of national survey data

Background The relationship between digital engagement and physical activity among Chinese populations remains unclear. This study examined this association and identified population-specific effects. Methods We analyzed data from 33,613 participants from CFPS 2020 and CHARLS 2020. Digital engagement was measured using a composite index (0–100) covering digital access, skills, health information behavior, and service use. Physical activity was assessed using IPAQ standards (MET-minutes/week). Multilevel mixed-effects models examined associations, with moderation analyses for age, urban–rural, and educational differences. Results Mean digital engagement was 48.3 ± 22.1, with marked urban–rural disparities (61.2 vs. 32.5, p < 0.001). Each 10-point increase in digital engagement was associated with 260 MET-minutes/week increase in physical activity (95% CI: 220–300, p < 0.001). The association showed an inverted U-shaped age pattern, strongest among 45–59 years ( β = 0.42). Despite lower digital engagement, rural areas showed stronger effects ( β = 0.34) than urban ( β = 0.23, p-interaction = 0.008). Health information searching ( β = 0.38) and digital health service use ( β = 0.35) had stronger effects than digital access alone ( β = 0.21). Conclusion Digital engagement positively associates with physical activity, particularly benefiting middle-aged adults and rural residents. Targeted digital health interventions could effectively promote physical activity in underserved populations.