A cross-cultural comparison of sleep duration between U.S. and Australian adolescents: the effect of school start time, parent-set bedtimes and extracurricular load

Abstract

STUDY OBJECTIVE: To test whether sleep duration on school nights differs between adolescents in Australia and the U.S. and, if so, whether this difference is explained by cultural differences in school start time, parental involvement in setting bedtimes and extra-curricular commitments. PARTICIPANTS: 385 adolescents aged 13-18 years (M=15.57,SD=0.95; 60% male) from Australia and 302 adolescents aged 13-19 years (M=16.03, SD=1.19; 35% male) from the United States. METHODS: Adolescents completed the School Sleep Habits Survey during class time, followed by an 8-day Sleep Diary. RESULTS: After controlling for age and sex, Australian adolescents obtained an average of 47 minutes more sleep per school night than those in the U.S. Australian adolescents were more likely to have a parent-set bedtime (17.5% vs 6.8%), have a later school start time (8:32am vs 7:45am) and spend less time per day on extra-curricular commitments (1h37m vs 2h41m) than their U.S. peers. The mediating factors of parent-set bedtimes, later school start times, and less time spent on extra-curricular activities were significantly associated with more total sleep. CONCUSIONS: In addition to biological factors, extrinsic cultural factors significantly impact upon adolescent sleep. The present study highlights the importance of a cross-cultural, ecological approach and the impact of early school start times, lack of parental limit setting around bedtimes and extracurricular load in limiting adolescent sleep