Sunrise, sunset, and adverse effects of the inflexible schedule on the health of students: Evidence from China

Abstract

Industrialization has changed the human life rhythm synchronized with the sunrise/sunset, yet human biological features cannot fully adapt to these changes. The unified time zone and inelastic schedule in China make it difficult to coordinate sunrise and sunset times with daily routines, potentially leading to health issues. This paper examines the effects of exogenous variations in sunrise/sunset times across different seasons and regions on the time allocation and health outcomes of school children in China. Using the China Family Panel Studies, we find that later sunsets lead to sleep deprivation, increased indoor leisure time, and reduced extracurricular learning and physical exercise, which can impair physical and mental health. However, rigid morning schedule prevents students from compensating for sleep by late wake-up. Moreover, non-boarding and G9/12 students are more negatively affected. Our findings highlight the costs of the discrepancy between sunrise/sunset times and rigid daily life schedules and suggest adopting more flexible schedules that account for the seasonal and regional changes in sunset times.