Does a delayed school start time cause students to exercise less? Evidence from South Korea

A delayed school start time (DSST), achieved by removing zero period, could change students' other time use during school as well as other forms of human capital accumulation. Using difference-in-differences, we find evidence that a DSST in South Korea reduced the time students spent in gym class without worsening students' health status. Combined with previous studies that provided evidence that DSSTs increased students' test scores, our results imply that a DSST can increase students' academic achievement without reducing other forms of human capital accumulation, although schools might change students' other time use.