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What if you knew that one simple daily habit would boost your teenager’s mental health three-fold, improve their grades and love of school, make them a better athlete, dramatically reduce their stress and anxiety, cut their chances of getting in a car accident in half, and ward off chronic health conditions like type 2 diabetes, obesity, and cancer? And what if this practice costs nothing and was completely natural. No downsides—only upsides to everything you care about in your teenager’s life.

Of course, you’d start today.

The irony is that we have this powerful panacea available to us at this very moment, and every day, we systematically neglect it. Yes, you’ve guessed it. It’s the life-fueling practice of sleep—and our teenagers are in the midst of the worst case of deprivation experienced by any population in history.

Modern-day teens are the most sleep-deprived group of any individuals the world has ever seen: while the majority of elementary school kids get the optimal amount of sleep on most nights, that number drops to about 30 percent by middle school, and by their senior year, only 5 percent of teens get optimal sleep on school nights. And the numbers keep slipping. In 2015, 58 percent more teenagers were severely sleep deprived than in 1991. A recent survey of sixty thousand American high school students measured how well teens are faring in terms of basic health recommendations for sleep, screen use, and exercise. Only 3 percent of girls and 7 percent of boys reached these targets.

As therapists and sleep specialists, we’ve watched this downward trend in teen sleep. A “perfect storm” (a concept we’ll explore throughout this book) of shifting biology, academic pressure, early high school start times, and a misconception that sleep is dispensable rather than essential, has been steadily chipping away at teen sleep. But while that storm has been brewing for decades, the explosion of technology has taken this storm to Category 5 hurricane levels. The smartphone is getting harder and harder to put down. Technology is ever more brilliant at keeping teens engaged and connected (teen sleep took a notable dip after 2011, as the smartphone gained popularity). Meanwhile, the academic load on students continues to increase and kids are being prepped for college applications when they’ve barely stopped playing tag on the playground. Like never before, teens’ sleep is being stolen from all sides.

To make matters worse, adolescence is a stage of life when proper sleep is vital and game changing—to a degree that few of us fully appreciate. Books on baby sleep are stacked high on our bedside tables, because no one doubts the importance of sleep to a growing baby. But the truth is, a teenager’s brain is doing through an equally important stage of growth (with potentially more life altering and consequential outcomes). Adolescence is an awe-inspiring and pivotal developmental phase, when the brain undergoes massive reorganization and growth, and much of that vital work happens during sleep. Missing sleep raises the risk of mental health issues, heightens teen stress at a neurochemical level, makes athletes more accident prone, and causes the brain’s memory storage to malfunction, which short-circuits learning and academic success. When sleep is missing, the ripple effects on mental and physical health are tremendous and exponential.

Even when we as parents try to protect sleep, we often feel like our hands are tied. Yes, most know our teen should get to bed on time, but they many of us feel frustrated and powerless, because the factors that truly limit sleep—insidious technology, academic overload and in some cases punishingly early high school start times—feel out of our control. What can they possibly do? (Who’s up for joining us in breaking into the headquarters of Big tech to change the algorithms that create increasingly addictive platforms and games? Or magically signing a bill to make middle and high schools across the world start no earlier than 8:30 a.m.) In all seriousness, what are parents, teens, and the people who care about them supposed to do with to protect growing teenage brains and bodies?

The answers are in this book. In the chapters ahead, we will help you regain what decades of science have shown as the mental and physical benefits of good sleep. Together, we will explore the wonders of the teenage brain, the surprising powers of healthy sleep, and the roadblocks to a teen’s full night of slumber. We’ll translate that knowledge into specific actionable steps that parents and teens—as well as school leaders and companies—can take, right now, to drastically transform sleep, and therefore health and well-being. We even have a “cheat sheet” for your teenager to read, so they feel personally motivated to engage in these simple practices. And along the way, you’ll find yourself engaging in better sleep—feeling healthier, happier and more patient as well. (What can we say? It’s never too late to start sleeping well.)

Teen Sleep Loss: Why It Matters
Sleep breathes life into the adolescent brain—it releases neurochemicals like serotonin and dopamine, that fuel teens with positivity, purpose, new ideas, passion, and sharp focus. It skyrockets hormones that strengthen and repair muscles. Sleep bolsters the immune system, decreases inflammation, and lowers the risk of chronic disease. If it seems like we could go on and on here, it’s true. There is no drug, supplement, or routine that can return the same multifaceted benefits as good sleep.

And not surprisingly, the consequences of teenage sleep deprivation are serious and wide-reaching. Sleep loss creates wear and tear on the brain and body that manifests in many of the mental health symptoms we see in today’s teenagers. According to the Pew Research Center, 7 in 10 teens say that anxiety and depression are major issues in their communities, and the number of teenagers who say they recently experienced depression increased 59 percent between 2007 and 2017. An increasing percentage of American youth say that they feel sad or hopeless, and tragically, the rate of suicide for fifteen-to-nineteen-year-olds has gone up 76 percent since 2007. Not coincidently, during this time, sleep has continued to shrink. As we’ll uncover in the next chapter, sleep loss raises stress levels, decreases the brain’s emotional regulation pathways, and amplifies the brain’s negative emotional centers. A sleep deprived brain sees the world through a negative lens, and skews towards sadness, frustration, anger, or hopelessness. A study of Chicago middle school kids found that those who got less sleep had lower self-esteem, lower grades, and higher levels of depression. A study of Chinese adolescents found that sleeping less than eight hours a night on a regular basis was associated with a threefold increase in the risk of suicide attempts. The connections between sleep and psychological wellbeing are direct and unmistakable. Mental health holds first place on every parent’s concern list—which means sleep should too.

Lack of sleep dampens activity in the prefrontal region of the brain—where our judgement, decision-making, and self-regulation live—which means sleep-deprived adolescents are at higher risk for accidents and poor decision-making. This turns out to be especially dangerous for teenagers, as we’ll explain in chapter 3, because of the unique way the brain changes in these years. Car accidents, injuries, and many more terrifying and life-altering events that keep parents awake at night are exacerbated by sleep deprivation. Substance use goes up as sleep time goes down. In fact, data from the CDC links insufficient sleep to most risky behaviors, like smoking, drinking alcohol, sexual activity, lack of physical activity—along with seriously considering suicide. One study showed that each hour of lost sleep carried a 23 percent increase in the risk of tobacco, alcohol, or marijuana use, and a 58 percent increase in suicide attempts. Fatalities from car crashes are now the leading cause of death among teenagers in the U.S., teen drivers are more than three times as likely as adults to be in a fatal crash, and sixteen-to-twenty-four-year-olds constitute half of drowsy driving-related accidents (even though they make up significantly less of the driving population). Nearly 1 in 10 seniors in high school said they’ve fallen asleep while driving, and researchers have repeatedly estimated sleep deprivation as having similar effects to alcohol consumption. Sleep researcher Wendy Troxel points out that we’d never knowingly condone our teens drinking alcohol and getting behind the wheel, but without realizing it as a comparable risk, parents hand their keys to sleep-deprived teenagers all the time.

High schoolers burning the midnight oil, with their laptops open late at night, sacrifice hours of sleep to keep up with academic demands,—but cramming facts while losing sleep turns out to be totally counterproductive. Sleep is needed to encode information and turn short-term memories into long-term ones. Without healthy sleep, the hippocampus, which is the region on the brain that encodes memories, essentially malfunctions, so students are unable to retain what they learned. Information goes in but it doesn’t stick. On the flip side, sleep improves focus and attention, so well-slept kids absorb information better and are more likely to care about and enjoy what they’re learning (which also helps them remember it later). Healthy sleep increases brain connectivity and decreases impulsivity and hyperactivity—meaning that kids who are considered to have behavioral issues are better helped with a full night’s sleep than a trip to the principal’s office.

Many teens are so under slept on weekdays that they resemble subjects in acute sleep deprivation studies—falling asleep in class, seeing the world through negative eyes, forgetting information, making mistakes, and generally walking around in a cloud. Still more will suffer a lower level (thirty to sixty minutes) of chronic sleep loss that builds over time. In both cases, the effects are significant. Sleeping too little, or sleeping at the wrong times, as is the case for many teens whose internal clocks are out of sync with school schedules, sets off a cascade of chemical events in the body that affects the nervous system, raises stress hormones and blood pressure, increases inflammation, increases unhealthy eating, lowers testosterone and other important developmental hormones, and more.

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Sleep is your secret health weapon
Sleep is not rest. It’s a vital activity with far reaching health benefits. For example, sleeping well leads us to healthy metabolism, eating behaviors, and weight—both now and in the future. Sleep regulates our body chemistry, which wards off future chronic health conditions like diabetes and heart disease. Cancer risk may even be affected by good sleep. Researchers injected mice with tumor cells under two conditions: one group was allowed normal sleep, while the other group had their sleep repeatedly disrupted. Mice whose sleep was disrupted had tumors twice the size as those who slept normally. Recently scientists have seen that sleep affects something called the “glymphatic system” in the brain, which is meant to eliminate toxins that have accumulated. When we sleep well, the brain’s glymphatic system completes this important cleaning work.

Sleep is also crucial to the immune system. In a lab experiment, researchers gave the flu vaccine to severely sleep-restricted and well-rested students. The sleepy subjects produced 50 percent fewer antibodies than those of well-rested students.
How Much Sleep Do Teens Need, and How Much Are They Getting?
How much sleep do you think adolescents need?
A. 6–7 hours
B. 7–8 hours
C. 9–10 hours

Most people answer B (although you may be on to us by now), when the answer is actually C. People tend to settle on B, because nine to ten hours sound like how much sleep a young child needs. But here’s a surprising notion: your teenager many need as much sleep now as he did in elementary school. This fact contradicts a widely held misconception we have about sleep—that kids need less of it as they grow. This turns out not to be true at all. Between the ages of ten and eighteen, sleep needs stay consistently high, and for many, this continues into early adulthood. Teens will sleep an average of 9.25 hours a night, if given the opportunity (a discovery that shocked scientists themselves, as we’ll learn about in the next chapter 3), and in some cases they may need more sleep than their younger siblings.[1] Many people remark to us, “My teen sleeps all the time!” What they mean is that, when given the chance, on the weekend or on vacation, their teen sleeps extraordinarily long hours. This is the body attempting to make up for an accumulating backlog of sleep deprivation.

We underestimate sleep needs because we think of teens as near adults. From a developing brain perspective, they are not. In fact, teens are beginning a new wave of brain reorganization and psychological maturation that will last well into their twenties, and sleep is when much of this transformative construction happens. When adolescents sleep, neural pathways are refined and strengthened, emotions are processed, learned information and memories are encoded, muscles repair and grow, and many other systems in the body complete essential tasks. Adolescents have a deep need for sleep because of the magnitude of these changes.