Short-term effects of temperature on physical activity and sedentary behavior in Chinese adults: An accelerometer-based analysis.

BACKGROUND: Understanding the short-term effects of temperature on physical activity and sedentary behavior, as well as adaptation patterns under extreme temperatures, will help China and other countries with similar climatic conditions implement targeted interventions to promote physical activity and enhance public health. METHODS: During 2020 and 2021, 22,511 China Kadoorie Biobank participants in the 3rd resurvey consented to wear an Axivity AX3 wrist-worn triaxial accelerometer for 7 consecutive days to assess their movement behaviors. To investigate the short-term effects of daytime temperature on physical activity and sedentary behavior, we used distributed lag nonlinear models combined with generalized estimating equations. The final analysis included 110,553 days of acceleration data from 19,977 participants from 10 Chinese cities. RESULTS: Temperature exhibited an inverted U-shaped association with overall activity and moderate-to-vigorous intensity physical activity (MVPA), with a peak at 26°C. In contrast, light-intensity physical activity (LIPA) showed an inverted N-shaped relationship with temperature, while sedentary behavior gradually increased. The maximum change in overall activity was a decrease of 13.33% (95% CI: 11.54% to 14.93%, cumulative lag 0 days) and 4.50% (95% CI: 2.65% to 6.32%, cumulative lag 4 days) under extremely low and high temperatures, respectively. Males and manual workers exhibited greater variability in both overall activity and MVPA across the temperature range. CONCLUSIONS: Our findings highlight the need for targeted interventions to mitigate the adverse effects of temperature on physical activity, with strategies tailored to specific groups, particularly sex and occupation.