Objectively Measured Association Between Air Pollution And Physical Activity In College Students In Beijing

PURPOSE: To examine the association between hourly air pollution on hourly physical activity (PA) among college students in Beijing, China. METHODS: A total of 340 participants (70.58% male) were recruited from the Tsinghua University, in Beijing, China. Accelerometers provided PA measures, including moderate-to-vigorous physical activity (MVPA), walking steps, energy expenditure for 7 consecutive days. Corresponding air pollution data by the Beijing Municipal Ecological Environment Bureau in the closed site (Wan Liu site) in Tsinghua University were collected including average hourly air quality index (AQI) and PM2.5 (μg/m3). Associations were estimated using linear individual fixed-effect regressions. RESULTS: A one level increase in hourly air quality index (AQI) was associated with an reduction in one-hour PA by 0.083 (95% confidence interval [CI] =-0.137, -0.029) minutes of MVPA, 8.822 (95% CI = -15.028, -2.617) walking steps, 0.653 (95% CI =-1.033, -0.273) kcals of energy expenditure. A 10μg/m3 increase in air pollution concentration in hourly PM2.5 was associated with a reduction in one-hour PA by 0.021 (95% confidence interval [CI] =-0.033, -0.010) minutes of MVPA, 2.232 (95% CI = -3.548, -0.916) walking steps, 0.170 (95% CI =-0.250, -0.089) kcals of energy expenditure. CONCLUSIONS: Although there is a negative trend between air pollution and PA, their impact on college students in Beijing seems limited.