Middle school start times: the importance of a good night's sleep for young adolescents.

With the onset of adolescence, teenagers require 9.2 hr of sleep and experience a delay in the timing of sleep. In the "real world" with early school start times, however, they report less sleep, striking differences between their school-weekend sleep schedules, and significant daytime sleepiness. Prior studies demonstrated that high schoolers with later school starts do not further delay bedtime but obtain more sleep due to later wake times. This study examined sleep-wake patterns of young adolescents attending urban, public middle schools with early (7:15 a.m.) versus late (8:37 a.m.) start times. Students (N = 205) were assessed at 2 time periods. Students at the late-starting school reported waking up over 1 hr later on school mornings and obtaining 50 min more sleep each night, less sleepiness, and fewer tardies than students at the early school. All students reported similar school-night bedtime, sleep hygiene practices, and weekend sleep schedules.