During a typical school week, Rhea Pallerla gets six to seven hours of sleep a night. But if it’s finals period or she has an especially large workload, the 16-year-old says, she’ll sleep as little as five hours. At school, it’s often difficult for her to focus. Sometimes she dozes off in her AP chemistry class.

“My sleep, frankly, has suffered since I started high school,” says Rhea. A sophomore at Heritage High School in Brentwood, California, she juggles academics and extracurriculars, including speech and debate club and writing for a student newspaper. But Rhea hardly stands out among her peers in getting too little sleep. It “is sort of a badge of honor,” she notes, “like the less sleep you get, the more disciplined you are.”

In fact, nearly 80 percent of American teens are sleep-deprived, according to the Centers for Disease Control and Prevention (C.D.C.). That means they’re regularly getting less than the 8 to 10 hours of sleep the C.D.C. recommends for people ages 13 to 18. Teens’ sleep has been on the decline over roughly the past two decades; today the average U.S. teen gets between six and seven hours per night.

“Teenagers will sometimes be surprised that they feel like they need more sleep when they’re, say, 16 than when they were 11,” says Heather Turgeon,
a psychotherapist and co-author of the book Generation Sleepless. “The brain and the body are changing so much . . . and much of that work happens at night when you’re sleeping.”

Sleep is critical for many important processes in our bodies, including maintaining a healthy metabolism, flushing toxins out of the brain, and helping the immune system fight off illness. During sleep, the brain releases growth hormones and develops connections that regulate decision-making, information processing, and self-reflection. These functions make sleep especially critical for teens, whose brains are still developing and whose bodies are experiencing growth spurts.

Rhea Pallerla is a 16-year-old student. During a regular school week, she gets six to seven hours of sleep a night. But if it’s finals period or if she has an especially large workload, she will get as little as five hours of sleep. She often has a hard time focusing at school. Sometimes she falls asleep in her AP chemistry class.

“My sleep, frankly, has suffered since I started high school,” says Rhea. She is a sophomore at Heritage High School in Brentwood, California. She is active in academics and extracurriculars, including speech and debate club. Rhea also writes for a student newspaper. She is not alone in getting too little sleep. It “is sort of a badge of honor,” she notes, “like the less sleep you get, the more disciplined you are.”

In fact, nearly 80 percent of American teens are sleep-deprived, according to the Centers for Disease Control and Prevention (C.D.C.). Teens are getting less than the 8 to 10 hours of sleep the CDC recommends for people ages 13 to 18. For the past 20 years, teens’ sleep has been declining. Today the average U.S. teen gets between six and seven hours per night.

“Teenagers will sometimes be surprised that they feel like they need more sleep when they’re, say, 16 than when they were 11,” says Heather Turgeon, a psychotherapist and co-author of the book Generation Sleepless. “The brain and the body are changing so much . . . and much of that work happens at night when you’re sleeping.”

Sleep is critical for many important processes in our bodies. It helps maintain a healthy metabolism, flushes toxins out of the brain, and helps the immune system fight off illness. During sleep, the brain releases growth hormones. It also develops connections that regulate decision-making, information processing, and self-reflection. These functions make sleep especially critical for teens. Their brains are still developing, and their bodies are still experiencing growth spurts.

Hormonal changes during puberty shift teens’ internal clocks, delaying when they feel tired to around 11 p.m. and their natural wake time to around 8 a.m. These biological changes can make waking up early for school especially difficult. Add to that the demands of homework, extracurriculars, and after-school jobs, plus the temptations of smartphones and the internet, which experts say all contribute to a major sleep crisis among teens.

Over the past 20 years, teen mental health has worsened drastically in the U.S. In 2021, the U.S. Surgeon General warned of a “devastating” mental health crisis among teenagers. In 2023, 40 percent of high schoolers reported having persistent feelings of sadness and hopelessness, according to the C.D.C. Many health experts say that the teen sleep crisis and mental health crisis are intertwined.

“Mental health is extremely sensitive to sleep,” says Andrew Fuligni, the director of the Adolescent Development Lab at the University of California, Los Angeles (UCLA). “Disrupted sleep or irregular sleep can lead to feelings of anxiety or depression. . . . Those in turn could also lead to more difficult sleep at night.”

When people don’t get enough sleep, the systems within the brain that help regulate emotions don’t function as well, Fuligni adds. Sleep disruption can also cause inflammation, which researchers have linked to depression.

Hormonal changes during puberty shift teens’ internal clocks. They begin to feel tired around 11 p.m. and their natural wake time shifts to around 8 a.m. These changes can make waking up early for school especially difficult. Homework, extracurriculars, and after-school jobs, plus time on smartphones and the internet, all add up to a major sleep crisis among teens.

At the same time, teen mental health in the U.S. has worsened over the past 20 years. In 2021, the U.S. Surgeon General warned of a “devastating” mental health crisis among teenagers. The C.D.C. reported in 2023 that 40 percent of high schoolers reported feeling sad and hopeless. Many health experts say that the teen sleep crisis and mental health crisis are connected.

“Mental health is extremely sensitive to sleep,” says Andrew Fuligni, the director of the Adolescent Development Lab at the University of California, Los Angeles (UCLA). “Disrupted sleep or irregular sleep can lead to feelings of anxiety or depression. . . . Those in turn could also lead to more difficult sleep at night.”

When people don’t get enough sleep, the brain systems that help regulate emotions don’t function as well, Fuligni adds. Interrupted sleep can also cause inflammation, which researchers have linked to depression.

Many health experts point to early school start times as a major contributor to the teen sleep crisis. While roughly 40 percent of U.S. high schools start at 8 a.m. or earlier, the American Academy of Pediatrics recommends a start time of no earlier than 8:30 a.m., to better align with teenagers’ circadian rhythms, or internal body clocks. Studies have shown that later school start times help boost students’ academic performance, reduce youth crime, and even improve driving records, as teens are less likely to doze off at the wheel.

Rhea says that on the days she’s the most sleep-deprived, she notices she’s less social at school.

“I tend to be closed off completely and isolate myself from my friends,” she says. Lack of sleep “has definitely affected my social life as well as my academic life.”

Some schools have responded to the sleep crisis by changing their schedules. In 2022, California became the first state in the nation to require that all public high schools start no earlier than 8:30 a.m. Lawmakers in New Jersey, New York, and Connecticut have introduced similar bills.

Many health experts say early school start times contribute to the teen sleep crisis. While roughly 40 percent of U.S. high schools start at 8 a.m. or earlier, the American Academy of Pediatrics recommends a start time of no earlier than 8:30 a.m. Starting school later would better align with teenagers’ circadian rhythms, or internal body clocks. Studies have shown that later school start times help boost students’ academic performance and reduce youth crime. There is even an improvement in driving records because teens are less likely to fall asleep at the wheel.

Rhea says that on the days that she sleeps less, she has noticed she’s less social at school.

“I tend to be closed off completely and isolate myself from my friends,” she says. Lack of sleep “has definitely affected my social life as well as my academic life.”

Some schools have changed their schedules in response to the sleep crisis. In 2022, California became the first state in the nation to require that all public high schools start no earlier than 8:30 a.m. Similar bills have been introduced in New Jersey, New York, and Connecticut.

“Our teens would be better off if school started later,” Connecticut State Senator Derek Slap told CT Insider. “People don’t dispute the science.”

Those in favor of letting teens sleep in point to districts such as Seattle Public Schools, which shifted high school start times from 7:50 a.m. to 8:45 a.m. in 2016. Research found the change gave students 34 more minutes of sleep on average and improved academic performance.

Spencer Sherr, 18, successfully lobbied his Birmingham, Michigan, school last year to delay the opening bell from 7:30 to 7:50 a.m., with the support of the advocacy group Start School Later. Before the change, he says, he constantly felt tired, and it was difficult to perform at his best in class.

“Sleeping in even an extra 20 minutes . . . makes a big difference,” he says. At school, he adds, “there’s definitely been an improvement in mood.”

Opponents of later school start times say that they create logistical challenges for school districts, such as having to reconfigure bus routes and after-school programs. And they pose problems for parents with inflexible work schedules. In California, responses to the later start time have so far been mixed among parents and students.

“Our teens would be better off if school started later,” Connecticut State Senator Derek Slap told CT Insider. “People don’t dispute the science.”

Those in favor of letting teens sleep in point to districts such as Seattle Public Schools. High school start times were changed from 7:50 a.m. to 8:45 a.m. in 2016. Research found the change gave students 34 more minutes of sleep on average and improved academic performance.

Spencer Sherr, 18, successfully lobbied his Birmingham, Michigan, school last year to delay the opening bell from 7:30 to 7:50 a.m., with the support of the advocacy group Start School Later. Before the change, he says, he constantly felt tired, and it was difficult to perform at his best in class.

“Sleeping in even an extra 20 minutes . . . makes a big difference,” he says. At school, he adds, “there’s definitely been an improvement in mood.”

People who disagree with later school start times say that they create logistical challenges for school districts, such as having to reconfigure bus routes and after-school programs. They also think it creates problems for parents with inflexible work schedules. In California, responses to the later start time have so far been mixed among parents and students.

“Because they are able to wake up later, teens go to sleep later and in the end get the same amount of sleep,” parent and teacher Adriana Aguilar told the San Diego Union-Tribune.

There are plenty of habits that teens can adopt to improve their sleep hygiene, including sticking to a regular sleep schedule and creating a screen-free wind-down routine at bedtime (see “Sleep Tips for Teens,” below). Structural changes, such as putting more restrictions on social media and reducing homework loads, are also critical to helping teens get the sleep they need, health experts say.

Rhea, the California student, says she’d like to see a shift in the way her classmates talk about sleep and hopes that teachers and administrators can more openly discuss the negative consequences of sleep deprivation.

At school, sleep “is just not seen as important,” she says. “I think we could have more discussions about sleep health.”

“Because they are able to wake up later, teens go to sleep later and in the end get the same amount of sleep,” parent and teacher Adriana Aguilar told the San Diego Union-Tribune.

There are plenty of habits that teens can adopt to improve their sleep quality. These include sticking to a regular sleep schedule and creating a screen-free wind-down routine at bedtime (see “Sleep Tips for Teens,” below). Health experts also suggest structural changes, such as putting more restrictions on social media and reducing homework loads.

Rhea, the California student, says she’d like to see a shift in the way her classmates talk about sleep. She hopes that teachers and administrators can more openly discuss the negative consequences of sleep deprivation.

At school, sleep “is just not seen as important,” she says. “I think we could have more discussions about sleep health.”