According to the Centers for Disease Control and Prevention, about 41 million Americans get six or fewer hours of sleep per night. For teens, it's even worse.
For most adolescents, nine hours of sleep is ideal. Unfortunately, very few are actually managing that. In fact, surveys show that less than 9 percent of teens get enough sleep. And the amount of rest they get decreases as they progress through high school. In fact, Cornell University psychologist James B. Maas, PhD, a leading sleep expert, goes so far as to call American teenagers "walking zombies" because they live on so little sleep.
What's preventing teens from getting the rest they need? An array of factors, including technology use, caffeine intake, heavy homework loads, extracurricular activities and schools with early start times. Plus, adolescents experience a shift in their internal biological clocks post-puberty; their circadian rhythms naturally keep them up later at night.
Research has found a clear link between sleep deprivation and teenage depression and anxiety. In a study of nearly 28,000 high school students, scientists found that each hour of lost sleep was associated with a 38 percent increase in the risk of feeling sad or hopeless, and a 58 percent increase in suicide attempts. Another study found that high school seniors were three times more likely to have strong depression symptoms if they had excessive daytime sleepiness.
Furthermore, lack of sleep can wreak havoc with adolescents' already turbulent emotions. In studies conducted at the University of Arkansas, people who lost a night of sleep responded with more emotion to stressors presented in the lab, leading researchers to conclude that sleep deprivation has a negative impact on the functioning of the emotional regulation circuit of the brain.
That means that a teenager who gets less shuteye will be more likely to have extreme emotional responses to daily events. These findings are especially troubling because teens are already at risk for poor emotional self-regulation; in adolescents, the prefrontal cortex – the portion of the brain that controls self-regulation – is underdeveloped. Lack of sleep adds fuel to the fire.
The Impact of Sleep Deprivation on Substance Abuse Risk
Along with regulating emotions, the prefrontal cortex also regulates executive functioning – decision-making and impulse control. As a result, teens who get less sleep tend to engage more frequently in risky behaviors.
Research shows that ongoing lack of sleep can increase teens' likelihood of using drugs and alcohol. A 2015 study found that sleep difficulties and hours of sleep can predict a number of dangerous adolescent behaviors, including binge drinking, drunk driving and unprotected sex.
Why the Timing of Sleep Matters
Even teens who manage to get the recommended nine hours may not be receiving the full benefit. That's because teens tend to go to bed late and sleep late – and, unfortunately for them, the quality of our sleep is better earlier in the night. "The time of night when you sleep makes a significant difference in terms of the structure and quality of your sleep," says Matt Walker, head of the Sleep and Neuroimaging Lab at the University of California–Berkeley.
Scientists have found that non-REM sleep (the type we experience between 10 pm and 3 am) is deeper and more restorative than lighter REM sleep (between 3 and 7 am). So teens who regularly go to bed at 3 am, for example, will get fewer hours of restorative non-REM sleep – even if they sleep till noon.
How Teens Can Get Better Sleep
Here are a few guidelines that can help teens develop better sleep hygiene.
Get up at the same time every day. A consistent sleep schedule will help teens regulate their sleep rhythms. If they do sleep later on weekends, it should only be for an hour or so more than usual.
Take naps when possible. Sleep experts recommend midday naps and other short bursts of sleep. In fact, studies show that deep sleep can help us function optimally, even if it's just a half-hour nap.
Unplug earlier. Along with keeping teens occupied late into the night, smartphones detract from sleep via the artificial light they emit, which stimulates more cortisol (the hormone that tells the brain to be alert and productive) than the sun itself.
Exercise. Research shows that people sleep significantly better and feel more alert during the day if they get at least 150 minutes of exercise a week.
Do yoga. Doing yoga before bed helps people fell asleep more easily and sleep longer. One study showed that young adults who regularly practiced yoga woke up fewer times in the night – a sign of better sleep quality.
Avoid sugar at night. Sugar destabilizes our glucose levels, creating a burst of energy. That's followed by a drop in blood sugar that, in turn, stimulates the release of adrenaline and cortisol – waking us up in the wee hours.
Along with boosting healthy sleep habits, these practices – regular exercise, yoga, limiting sugar intake and reducing smartphone use – all produce additional mental health benefits independent of their positive impact on sleep. It's a win-win for teens.