Backgrounder: Later School Start Times

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the demands older students face in academics, extracurricular activities, social opportunities, after-school jobs, and other obligations.

"Sleep isn’t a priority for teenagers, and it typically isn’t made one by parents or schools."

--Jodi Mindell, PhD, Director of Graduate Program in Psychology, St. Joseph’s University and Children’s Hospital of Philadelphia

The School Start Time Issue

Adolescent sleep deprivation is largely driven by a conflict between teens’ internal biological clocks and the schedules and demands of society. Therefore, it makes sense to look at school start times, which set the rhythm of the day for students, parents, teachers and members of the community at large.

"Given that the primary focus of education is to maximize human potential, then a new task before us is to ensure that the conditions in which learning takes place address the very biology of our learners."

Mary A. Carskadon, PhD, Director of E.P. Bradley Hospital Research Laboratory and professor in Department of Psychiatry and Human Behavior at Brown University School of Medicine

Research on School Start Times and Biology

In a project spearheaded by Dr. Mary A. Carskadon and colleagues, researchers investigated what would happen to sleep and circadian rhythms in a group of young people for whom the transition from junior high to senior high required a change in school starting time from 8:25 am to 7:20 am (Carskadon et al., 1998).

The 25 students completed the study at two time points, in the spring of 9th grade and autumn of 10th grade. The students kept their usual schedules, wore small activity monitors on their wrists, and kept diaries of activities and sleep schedules for two consecutive weeks. At the end, participants came to Carskadon’s sleep lab for assessment of the onset phase of melatonin secretion, an overnight sleep study, and daytime testing with MSLT. The in-lab sleep schedule was fixed to each student’s average school night schedule, based on data from the wrist monitors.

Carskadon and colleagues found that in the 10th grade:

  • On a typical school morning, the students woke up earlier for high school, but only 25 minutes earlier instead of the 65