A rising percentage of U.S. teens aren’t getting enough sleep

The percentage of U.S. high school students who aren’t getting enough shut-eye is climbing.

U.S. medical societies recommend that teens sleep eight to 10 hours each night. But in 2023, 77 percent of high school students reported slumbering fewer hours than that, up from 69 percent of those surveyed in 2007. The overall rise was due to a jump in those reporting five hours of sleep or less, researchers report March 2 in the Journal of the American Medical Association.

The study analyzed data from the Youth Risk Behavior Study, a long-term, national survey of students in public and private high schools. Seven hours of sleep or less describes insufficient sleep, while five hours or less counts as very short sleep. The percentage of students reporting insufficient sleep remained about the same from 2007 to 2023. But the percentage of very short sleepers rose from 16 to 23 percent.

Narrowing in on different demographic groups, there were larger climbs among Black students compared with white students, but all groups saw increased percentages of those getting inadequate sleep.

A slew of behavioral health risk factors, including mental health issues and substance abuse, can make it difficult to get enough sleep. Nearly all the groups at higher risk reported higher percentages of too little sleep. But the rise among students who weren’t at risk equaled or surpassed those of students with risk factors. This broad trend of fewer z’s suggests the culprit is larger structural problems rather than individual issues, the research team notes. One example is early high school start times.

Around the time puberty starts, there is a big shift in sleep-wake cycles for most teens. It leads to a delay of as much as two hours in falling asleep and in waking up, compared with their cycles in past years. This delay is thought to be due in part to timing changes in the release of the sleep-wake cycle hormone melatonin. It means most teens have a hard time falling asleep before 11 p.m. or waking up before 8 a.m.  

Inadequate sleep affects teens’ ability to think and increases the risk of physical and mental health harms. Research has shown that later high school start times benefit students. A study of five Minnesota high schools followed students over about two years as two schools delayed their first bell by an hour or so and three kept theirs at 7:30 a.m. The students with a later start got more sleep and had fewer symptoms of depression than their peers with an early start.