Evidence · Sleep
Are children getting enough sleep?
Most American high school students sleep less than experts recommend on school nights, and research links short sleep to problems with mood, attention, learning and safety.
The short answer
Sleep experts say children ages 6 to 12 need 9 to 12 hours of sleep a day, and teens need 8 to 10. In 2025, only about 1 in 4 U.S. high school students got at least 8 hours on a school night. In 2013, 32 percent did. Studies link short sleep in children to problems with attention, mood, learning, injury risk and weight. Phones in the bedroom and early school start times both go with less sleep, and families and schools can change both.
How much sleep do children need?
In 2016, the American Academy of Sleep Medicine published a consensus statement on sleep for children and teens in the Journal of Clinical Sleep Medicine. It sets these ranges for each 24 hours, on a regular basis:
- Infants, 4 to 12 months: 12 to 16 hours, including naps.
- Ages 1 to 2: 11 to 14 hours, including naps.
- Ages 3 to 5: 10 to 13 hours, including naps.
- Ages 6 to 12: 9 to 12 hours.
- Ages 13 to 18: 8 to 10 hours.
The CDC uses the same ranges on its sleep page. It also lists 14 to 17 hours for newborns up to 3 months old. The sleep academy's statement links regularly sleeping less than these amounts to attention, behavior and learning problems.
How many children fall short?
The CDC's Youth Risk Behavior Survey asks high school students how long they sleep on an average school night. In 2025, about 1 in 4 got at least 8 hours. The share falls as students move through high school. It was 31 percent in 9th grade and 20 percent in 12th grade. Boys did slightly better than girls, at 26 percent against 22 percent.
Younger students fall short too. In 2015, 57.8 percent of middle school students in nine states slept less than 9 hours on school nights. That sample covers only those nine states, not the whole country.
The National Survey of Children's Health asks parents about their children's sleep. From 2016 to 2018, 34.9 percent of children ages 4 months to 17 years slept less than recommended. The share was 40.3 percent for infants and 37.4 percent for children ages 6 to 12. Short sleep was more common in lower-income homes. It reached 45.6 percent below the poverty line, against 26.0 percent in the highest income group.
Newer data from the same survey show a similar picture. In 2020 and 2021, 37 percent of children ages 4 months to 5 years did not get enough sleep. States ranged from 25 percent in Minnesota to 50 percent in Louisiana.
The two surveys ask different people. Parents answer for their children in the national survey. High school students answer for themselves in the CDC youth survey. The youth survey also asks only about school nights.
Is it getting worse?
Yes, for high school students. The share who got at least 8 hours on school nights was 32 percent in 2013, 27 percent in 2015, 25 percent in 2017 and 22 percent in 2019. Most of the decline came before the pandemic. Since 2019, the share has held between 22 and 24 percent. The CDC rates the trend from 2015 to 2025 as worsened.
The same years brought sharp changes in teen mental health and in phone use. Our pages on children's mental health and phones and social media cover those trends. The survey data alone cannot show what caused the drop in sleep.
What is short sleep linked to?
The sleep academy's 2016 statement links too little sleep in children to accidents, injuries, high blood pressure, obesity, diabetes and depression. In teens, it also links short sleep to higher risk of self-harm, suicidal thoughts and suicide attempts. Much of this research is observational. It shows a link, not proof of cause.
One experiment tested cause directly. Researchers randomly assigned 56 healthy students ages 15 to 19 to 5 or 9 hours in bed for seven nights. In the 5 hour group, attention, working memory and executive function declined steadily. These students also grew sleepier and reported less positive mood. After recovery sleep, their sustained attention and sleepiness still had not returned to baseline.
Short sleep also tracks with risky behavior. A CDC analysis found that high school students who slept 7 hours or less were more likely to report injury-related risk behaviors than students who slept 9 hours. Students who slept 7 hours were about 1.5 times as likely to report drinking and driving. They were also more likely to text while driving and skip seatbelts.
Weight is another link. A 2018 review pooled studies that followed children forward in time. Short sleepers had a 58 percent higher risk of becoming overweight or obese, across 75,499 participants. These studies show an association. Our page on what American children eat covers diet.
Do phones and screens at bedtime matter?
The evidence points to a link, and a few habits stand out. A 2016 review in JAMA Pediatrics combined 20 studies of 125,198 children. Children who used a media device at bedtime had about twice the odds of too little sleep. Children who only had a device in the room at night, without using it, also had higher odds of short sleep and daytime sleepiness.
A 2024 study followed 9,398 American children ages 11 and 12 for one year. A TV or internet-connected device in the bedroom predicted shorter sleep a year later. Children who left the phone ringer on overnight had more sleep disturbance and shorter sleep than children who turned the phone off. Texting, music and social media at bedtime each predicted shorter sleep. The CDC also notes that screens stored in bedrooms go with shorter sleep, later bedtimes and poorer sleep quality.
Trials give a more mixed result. In a Danish randomized trial, 89 families cut recreational screen use for two weeks. The change did not change the children's sleep. It did raise their active leisure time by 45 minutes a day. Our page on free play and independence looks at how children spend that time. Our page on phones and social media covers the wider evidence on devices.
Do later school start times help?
Teenagers' body clocks shift later, so early start times cut into the 8 to 10 hours they need. The American Academy of Sleep Medicine recommends that middle and high schools start at 8:30 a.m. or later.
Seattle offers a direct test. In fall 2016, the district moved high school start times from 7:50 to 8:45 a.m. Researchers put wrist monitors on sophomores at two high schools before and after the change. Median school-night sleep rose by 34 minutes, from 6 hours 50 minutes to 7 hours 24 minutes. Median grades rose from 77.5 percent to 82 percent. First-period absences and tardies fell at Franklin High School, where most students come from low-income homes. The other school saw no change in attendance. The study compared students before and after the change. It did not randomly assign schools.
California made later starts a state law. Senate Bill 328 of 2019 requires middle schools to start no earlier than 8:00 a.m. and high schools no earlier than 8:30 a.m. The rule applied by July 1, 2022, with an exception for rural school districts.
Florida passed a similar law and then softened it. House Bill 733, signed in May 2023, set the same 8:00 and 8:30 a.m. limits. They were due to take effect by July 1, 2026. In 2025, the Legislature passed Senate Bill 296 without a single no vote. Under that law, a district or charter school counts as compliant if it files a report with the state by June 1, 2026. The report must list its start times and describe the impact and any unintended consequences of a later start. Senate staff expected that some districts would not move to later start times as a result.
What helps at home?
A regular bedtime matters. In the national survey of children's health, children with a regular weeknight bedtime had less short sleep: 27.5 percent, against 38.6 percent without one. The CDC also reports that teens whose parents set their bedtimes usually get more sleep.
The CDC lists everyday habits that support sleep. They include the same bedtime and wake time every day and a quiet, cool bedroom. The CDC also advises turning off electronic devices at least 30 minutes before bedtime. It adds avoiding caffeine in the afternoon and evening, and exercising regularly.
What Restore Childhood is doing
Restore Childhood is a 501(c)(3) that makes films, reporting and tools for everyone who cares about children. Its film 15 DAYS covers America's pandemic school closures. It publishes reporting on its Substack. This page is part of a series of plain evidence pages on childhood and school.
What you can do now
- Look up the recommended hours for each child's age. Count back from wake-up time to set a bedtime.
- Keep the same bedtime and wake time on school nights, and as close as possible on weekends.
- Charge phones, tablets and laptops outside the bedroom overnight.
- Turn screens off at least 30 minutes before bed, and turn phone ringers off.
- Ask your school board what time your middle and high schools start, and check your state's law.
- Share this page with a teacher, coach or school board member.
Related
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