The Evidence on Kids, Sleep, and School Start Times
Research shows starting school later is better for kids.
Posted Aug 09, 2018
It’s nearly time for kids across the country to head back to school and that means—for most kids—waking up bright and early. While early mornings are not often problematic for younger kids, tweens and teens often struggle to get up in the morning.
Science demonstrates that when young people begin puberty, their biological clocks shift; they typically become sleepy later—as late as 11 p.m.—and need to sleep later in the morning to get the recommended 8 to 10 hours of sleep each night.
Yet the vast majority of middle and high schools in the U.S. begin before 8 a.m. If you factor in travel time, it means many young people have to wake up in the early morning hours.
A large body of evidence documents ill effects on youth who don’t get enough sleep. Young people who regularly get less than eight hours of sleep per night are more likely to be overweight, suffer from depression, engage in risky behaviors (such as drinking, smoking tobacco, and using drugs), and perform poorly in school.
Two separate literature reviews have documented that when middle and high schools start later in the morning, kids are happier and healthier. One analysis combined data from six separate studies and found that in schools with later start times, students were less likely to experience depression, consumed less caffeine, were more likely to be on time to class, and were less likely to fall asleep during class. A second analysis of 38 studies found that delaying school start times helps young people to get significantly more sleep each night. As a result, students’ attendance and grades improved and they were less likely to get into a car accident. The American Academy of Pediatrics has recommended delaying start times for middle and high schools to 8:30 a.m. or later.
You might start by using the available evidence to lobby your school district leaders for moving the start time. Share the evidence with your teenage children as well. Youth who understand the importance of getting enough sleep are more likely to make an effort to go to sleep earlier.
Practice good sleep hygiene to set an example for your child. That means leaving screens out of the bedroom and avoiding them an hour before bedtime, only using your bed for sleeping, and cutting out caffeine after 2 p.m.
The bottom line: Once kids enter puberty, their bodies naturally want to go to sleep later and wake later. Helping your teens to get at least eight hours of sleep each night can help them to be happier and healthier.
For more information on our work solving human problems, please visit Cornell University's Bronfenbrenner Center for Translational Research’s website.