Associations of weather conditions with adolescents' daily physical activity, sedentary time, and sleep duration

Weather has been recognized as an environmental factor that affects daily activities. However, the effects of a humid subtropical climate on daily activity behavior are unclear. This study investigated the associations of weather conditions with physical activity (PA), sedentary time (ST), and sleep duration in a sample of 740 Hong Kong adolescents (mean age: 14.7 ± 1.6 years). The activPAL was used to assess the time spent during moderate to vigorous PA (MVPA), ST, and sleep. Weather data (e.g., temperature, relative humidity, rainfall amount, and sunlight duration) were obtained from the Hong Kong Observatory. Linear mixed models were constructed to examine the associations of weather conditions with the durations of MVPA, ST, and sleep on weekdays and weekend days, respectively. The analysis included valid data from 561 students (51.9% male). Among Hong Kong adolescents, a higher relative humidity was associated with reduced MVPA on weekdays and weekends, more ST on weekdays, and a longer sleep duration on weekends. A longer duration of sunlight induced less MVPA on weekends, but a longer sleep duration on weekdays. On weekends, higher temperatures correlated with increases in MVPA and ST but a decrease in sleep duration. Rainfall correlated inversely with sleep duration and positively with ST on weekdays. The associations of rainfall with MVPA exhibited opposite trends on weekdays and weekends. In summary, the relationships between weather conditions and daily activities exhibited day-type patterns. The findings suggest that environment-controlled indoor PA should be recommended during weather conditions of high relative humidity and higher temperatures.