Cruel biology: Why teens cannot get enough sleep in the school year

Owen Lanahan, 15, texts his friends and watches Youtube videos on how to create hip-hop beats at night in his room at his home in Portland, Ore., July 1, 2014. With myriad electronic ways to socialize, gossip and explore hobbies, tech-addicted teenagers are getting even fewer hours of sleep — a trend labeled vamping after the other legendary creatures of the night. (Leah Nash/The New York Times)

As adolescent rites of passage go, this one is extra obnoxious. The life stage when growing teens could really use a good night's sleep is the same time their bodies are programmed to stay up way too late. The Child Mind Institute sets the optimal amount of sleep for teens at 9 hours per night. That's the level that allows a teen's body "to function optimally—to be physically, mentally and cognitively healthy," the CMI explained.

Then, in the very next breath, it relayed the reality: Only about 8% of teens get enough sleep. "The rest live with chronic sleep deprivation—some mild to moderate, but more than half (59%) with severe sleep deprivation, meaning they sleep on average six hours or less most school nights," CMI added.

According to a 2017 study out of San Diego State University, two of five adolescents slept fewer than 7 hours a night. And while it might seem like a function of "night owl" personality or simply rebellion, it's actually cruel biology. When adolescents reach a certain age, their circadian rhythms make it difficult for them to sleep on a healthy schedule. Essentially, when puberty sets in, a teen's body begins a shift in sleep-wake cycles, according to the American Academy of Pediatrics, with the natural inclination to sleep being shifted up to two hours later.

This circadian rhythm issue makes teens literally want to go to bed later. When school is in session, the developmental stage is particularly toxic to teens and their families. School systems select high school schedules based on factors like when transportation is available and the most convenient hours for teachers. The AAP went so far as to urge schools to pay more attention to teens' sleep needs in 2014.

"Studies show that adolescents who don't get enough sleep often suffer physical and mental health problems, an increased risk of automobile accidents and a decline in academic performance," the AAP warned. "But getting enough sleep each night can be hard for teens whose natural sleep cycles make it difficult for them to fall asleep before 11 p.m. – and who face a first-period class at 7:30 a.m. or earlier the next day." The academy recommended middle and high schools delay the school-day start until at least 8:30 a.m. but gained little traction.

So teens and their parents are left to cope with what can only be described as a destructive cycle. A 2014 study from the Department of Psychology at the University of California–Berkeley, for example, associated late school year bedtime with "worse educational outcomes and emotional distress 6–8 years later." The study employed three "waves" of data to evaluate circadian patterns of 2,700 7th through 12th graders. They found that at every phase of the teen years, "late school year bedtime was associated with shorter total sleep time cross-sectionally, whereas late summertime bedtime was not," the researchers wrote. "Across Waves I and II, more than three quarters of adolescents who went to sleep at 11:15 a.m. or later during the school year or 1:30 a.m. or later during the summer reported sleeping fewer than the recommended 9 hours."

Circadian rhythms may kick off the tendency to want to stay up later, but Gen Z teens who spend a lot of time online decrease their odds of ever getting a good night's sleep. According to the San Diego State researchers, teens who spent 5 hours online per day were almost around 50 percent more likely not to get even seven hours of sleep per night when compared to teens who had just an hour of screen time per day.

And technology usage close to bedtime, which is almost synonymous with the stereotypical teen social experience, puts good sleep even further out of reach. A study published in the February 2018 Journal of Adolescent Health used surveys with the parents of 234 adolescents to conclude that kids ages 8-17 who used technology at bedtime didn't sleep as long or as well. Using cell phones, television, video games or computers right before bed also made it far more likely that a teen would wake up to text in the middle of the night and experience increased levels of morning fatigue.

Certainly, there's an impulse to "let teens be teens" and avoid confrontation in favor of the attitude "it's all part of growing up." But the damage from poor sleep has dire consequences for the kids during the school year, and late school year bedtimes are clearly linked to not getting the recommended amount of sleep.

The UCLA–Berkeley researchers urge parents to target bedtime to reduce the functional impairments associated with too little sleep, as well as improving academic and emotional outcomes. But how can parents get there when the teen years are already fraught with conflict and emotion? The Child Mind Institute experts recommended these strategies for combating teen sleep deprivation:

Get the screens off at least an hour before bedtime. This counters the "blue light" that sends "a signal to the brain which suppresses the production of melatonin and keeps kids from feeling tired," pediatrician Max Van Gilder told CMI.

Limit snacks after dinner. "Adolescents, many of whom have control over their diet for the first time, are prone to eating and drinking on an ersatz schedule, as a means to self-regulate, or to stay awake, or just because they can," CMI said. "But the bag of chips, or the cookies at 1 a.m., or caffeine any time after dinner—whether or not they help get the essay written—can postpone sleep, and harmfully."

Try melatonin and other circadian rhythm boosters. Van Gilder told CMI he "frequently recommends that teens who have trouble sleeping try taking a low dose (2-3 mg) of melatonin (a non-prescription vitamin which can be purchased at the drugstore) one to two hours before it's time to go to bed to help jumpstart melatonin production."