Discrepancy in wake-up time on school days and free days is associated with daytime sleepiness, lowered mental/physical health and poor academic performance

Abstract

This cross-sectional study was conducted to assess sleep habits between students with/without a discrepancy of ≥2 hrs in wake-up time (WUT) on school days and free days, and to determine whether the discrepancy is associated with daytime sleepiness, lowered mental/physical health and poor academic performance. A total of 4,392 students in 13 junior high schools completed a self-administered questionnaire including demographic information, sleep-wake patterns, daytime sleepiness, irritability and academic performance. We classified the students into two groups: those with/without a discrepancy between school day and free day WUT. The discrepancy prevalence was 38.4%. More students with the discrepancy skipped breakfast and did not attend a school club activity compared to those without the discrepancy. They also went to bed 22 min later and slept 21 min less on school days than those without the discrepancy. In a generalized linear mixed model, the discrepancy was associated with daytime sleepiness, irritability and poor academic performance. The WUT discrepancy of ≥2 hrs with a delayed circadian rhythm can be associated with lower mental/physical health and poor academic performance among adolescents.