Teens are getting less sleep, a trend that will impact their ability to learn and do well in school. But don’t rush to blame cellphones and social media, say the authors of a new study.
Researchers from several prominent universities examined the self-reported sleep habits of nearly 130,000 teens. They found that the number of teens getting insufficient sleep, defined as seven hours or less a night, rose from 69% in 2007 to 78% in 2023, the most recent year for which data was available.
That trend was driven, in large part, by a sharp rise in adolescents who are getting very little sleep, said Tanner Bommersbach, a child and adolescent psychiatrist and assistant professor of psychiatry at the University of Wisconsin-Madison and one of the authors of the study.
The number of teens getting less than five hours of sleep a night has increased from 16% to 23% during that time period.
“We know that sleep plays a really critical role in adolescent brain development,” Bommersbach said. “So when large numbers of teens aren’t getting enough sleep, it really raises concerns about the downstream effects that that could be having on their mental health, on their academic performance, on their engagement and risk behaviors.”
The data for the study—which was conducted by researchers from Columbia University, University of Connecticut, University of Wisconsin, and Yale University—comes from the national Youth Risk Behavior Survey, a representative survey of high school students that’s administered by the U.S Centers for Disease Control and Prevention in schools every other year. The findings were published in March in the Journal of the American Medical Association.
What’s interesting, said Bommersbach, is that the analysis found teens across the board are getting less sleep—whether or not they have what are considered risk factors for poor sleep—such as spending a lot of time on screens or using substances.
“Social media and screen time before bed gets a lot of blame, and certainly that contributes to insufficient sleep,” he said. “But what we found was that insufficient sleep is rising just as much among teens who don’t use social media as teens who use a lot of social media.”
Poor sleep has increased across all groups of students—by sex, grade, race, and ethnicity, the study found. Insufficient sleep was still more common among teens with risk factors, the study found, it’s just that poor sleep among kids without risk factors is rising at the same or a greater rate.
Bommersbach said that means that it’s unlikely that individual risk behaviors are the sole cause of adolescents’ declining sleep and that there’s likely some larger, societal factors or trends impacting how much shut eye teens get.
The study couldn’t pin down what exactly those factors or trends might be due to limitations in the data.
But Bommersbach has some ideas: Early school start times and extracurricular activities that get students up early or keep them up late might be behind teens getting less sleep, he said.
Another hypothesis is that parents are monitoring their children’s sleep duration and quality less than they have in the past, said Bommersbach.
“Then there also may be a societal normalization of not getting enough sleep,” he said. “As a society, we’ve accepted that amongst adults, amongst parents, and amongst kids that that’s normal.”
What schools can do to improve adolescents’ sleep
The fact that a quarter of adolescents are getting less than five hours of sleep a night has significant implications for students and schools, said Bommersbach.
Experts recommend that teens get eight to nine hours of sleep a night and keep regular sleep schedules where they wake up and go to bed at roughly the same times every day, including weekends.
“Study after study finds that teenagers who get more sleep report better mental health, better academic performance, and less engagement in risk behaviors,” said Bommersbach. “This research literature is really well established.”
Schools are in a unique position to help improve teens’ sleep, said Bommersbach. Studies have found that pushing back school start times can help, he said.
“School districts that move to later school start times are associated with kids getting more sleep,” he said. “It’s associated with kids reporting improved mental health symptoms. And it’s been associated with greater academic engagement and greater academic performance.”
Changing school start times, which requires shuffling complex bus schedules, is no easy task for school districts. But there are other steps schools can take to address the problem.
Schools can educate students and families about healthy sleep habits and why they’re important. That includes putting away screens a few hours before bed time and maintaining regular sleep schedules, Bommersbach said.
Schools also have control over school-sponsored extracurricular activities.
“Paying attention to when they’re holding practices in general, trying to avoid very early morning practices and trying to avoid late evening rehearsals or practices too. That’s another way for schools to encourage healthy sleep cycles for their students,” he said.
