A growing body of research shows that delaying high school start times helps students get more of the sleep they need each night. What is less known is how school policies delaying start times might influence other sleep-related behaviors, such as being late to class. A new study from the University of Minnesota School of Public Health recently examined the impacts of delayed start policies and found teens attending a school with a start time that allows them to sleep in later on school days experience less daytime sleepiness and school tardiness.

The study was led by PhD student Kaitlyn Berry and published in the Journal of Adolescent Health. The research was a part of the larger START study, led by Berry’s advisor, Associate Professor Rachel Widome. 

Berry and the research team studied students from five Minnesota high schools, gathering information about their sleep habits and behaviors. Students were first surveyed in ninth grade when all five schools started early, at approximately 7:30 a.m. After the first year, two of the five schools delayed their start times by about an hour to 8:30 a.m. The study looked specifically at the results of delaying school start time on waking too early and not being able to fall back asleep; being told to wake multiple times in the morning; sleeping past noon; oversleeping and being late to class; falling asleep in class; and feeling sleepy daily.

The study found that students in schools that changed policy to delay start times reported smaller than usual increases as they age through school in reports of feeling sleepy daily and being late to class due to oversleeping compared to students in schools that continued to start early.

“Adolescents rarely get enough sleep on school nights and commonly experience problems, such as feeling sleepy during the day,” said Berry. “Delaying high school start times does more than just extend sleep hours; these policies appear to help adolescents over-sleep less often, feel less sleepy during the day, and be more present in school.”

The researchers recommend that school administrators prioritize later high school start times as a durable and transformative strategy for improving adolescent sleep and well-being.