Abstract
great importance is attached to physical exercise and health of students, yet the precise manner in which time devoted to sports contributes to students' cognitive development remains inconclusive. Based on the two-wave panel data of China Education Panel Survey, this paper empirically examines the impact of daily physical exercise duration on junior high school students’ cognitive abilities by using two-way fixed-effect estimation. The findings reveal a nonlinear relationship, specifically an "inverted U" pattern, between daily physical activity time and students' cognitive performance. The cognitive return rates of time investment to sports reach the peak around 48 minutes per day. Sports enhance cognitive abilities by bolstering students' emotional stability, resilience, and physical well-being. Furthermore, the daily time allocated to physical activities affects students' cognitive performance differentially, with those of poorer physical fitness and those attending non-urban schools deriving greater benefits. Consequently, this study offers policy implications for educational governance, urging school administrators to devise schedules that optimize the efficiency and utility of students' time invested in sports.