Abstract

Background: Physical activity (PA) exerts a significant impact on global health and has been associated with a reduced risk of the common cold. This study aims to examine the correlation between physical activity and the frequency of colds among junior high school students in China.

Methods: A cross-sectional study was conducted among 356 middle school students aged 12—13 in Wuhan, Hubei Province, China. Twenty-four-hour movement behaviors were measured using an ActiGraph wGT3X-BT accelerometer, and participants reported the number of cold episodes over the past year. Compositional linear regression and isotemporal substitution models were employed to analyze the association between time allocation to 24-hour movement behaviors and the frequency of colds, and to predict changes in frequency of colds following time reallocation among these behaviors.

Results: 1) The time spent in moderate-to-vigorous physical activity (MVPA) was the most stable component of 24-hour movement behaviors among middle school students. When activity patterns changed, the highest probability of time reallocation occurred with light physical activity (LPA). 2) A significant association was observed between 24-hour movement behaviors and the frequency of colds among middle school students. Specifically, the proportion of MVPA time was negatively correlated with the frequency of colds among middle school students. The proportion of time spent in sleep (SP) was positively associated with the frequency of colds. No significant associations were observed between time allocation in sedentary behavior (SB) or light physical activity (LPA) and the frequency of colds. 3) The 15-minute isotemporal substitution model predicted significant reductions in the frequency of colds when replacing both sedentary behavior (SB) and sleep (SP) with MVPA. Conversely, when MVPA was replaced by either SB or SP, the frequency of colds increased significantly. Notably, the substitution of SP with MVPA demonstrated the most substantial effect in reducing the frequency of colds. 4) The dose-response relationship (ranging from -30 to +30 minutes) revealed asymmetric effects on the frequency of colds when mutually substituting MVPA with either SB or SP.

Conclusion: The results suggest that schools, students, and parents should prioritize the integrated effects of 24-hour movement behaviors and the moderate transformation of SB and SP to MVPA to reduce the frequency of colds among middle school students.