A 25-Minute Delay in School Start Time May Help Teens

Martin T. Stein, MD

It extended sleep duration and improved daytime mood.

Chronic sleep deficit in adolescents has been associated with crashes related to drowsy driving; obesity; cardiovascular disease; and impaired mood, attention, memory, and executive function. Inadequate sleep has also been associated with worse academic performance and decreased motivation to learn. Early start times in school may contribute to sleep deprivation. By studying a modest change to school start time in a coeducational boarding high school, these researchers eliminated environmental variables that could affect sleep (e.g., morning and evening routines, sleeping environments, and afterschool employment).

During the winter semester, the usual school start time of 8:00 AM was experimentally delayed 25 minutes. Before and during the winter semester, 197 adolescent participants (mean age, 16 years) completed the standardized School Sleep Habits Survey, which correlates well with sleep diary and actigraphy data.

With the delayed schedule, average school-night bedtimes did not change significantly, but average school-night sleep duration increased significantly by 29 minutes. The percentage of students who received ≥8 hours of sleep on a school night increased from 18% to 44%. Daytime sleepiness, depressive symptoms, and caffeine use were significantly reduced. Among 71 students who completed the survey after the earlier start time was reinstated, sleep duration returned to baseline.

Citation(s):

Boergers J et al. Later school start time is associated with improved sleep and daytime functioning in adolescents. J Dev Behav Pediatr 2014 Jan; 35:11.