The Science Behind Tired Teens

Getting my kids out of bed in the morning when they were teenagers felt like an epic battle of wills. I remember my son Brian begging for just five more minutes of sleep as if his life depended on it. Convinced that his fatigue was caused by going to bed too late, we tried to convince him to close his eyes earlier than eleven o'clock.

"I'm just not tired!" he would protest. "You can make me go my room, but I'm not going to be able to sleep!"

All three of my kids went from cheerful early risers to exhausted night owls when they hit adolescence. It seemed that every parent we talked with was experiencing the same patterns with their own teenagers--alert at night, comatose in the morning, and practically hibernating on the weekends.

Sleep and the Teen Brain

The explanation for how Brian turned into a night owl is, like so many things, found in the teen brain. Perhaps you've heard of the hormone melatonin. I like to think of it as "sleepy." When it gets dark a part of the brain called the hypothalamus sends a message to the pineal gland to increase production of melatonin. As melatonin concentrations rise, we feel more and more sleepy. After we've gotten sufficient rest, melatonin dips and we wake up.

Beginning at puberty, this cycle changes. Young people experience melatonin surges later at night and melatonin dips later in the morning. The result is a night owl who hasn't gotten near enough sleep when the alarm rings for school at 6 AM.

Complicating things even more, adolescents need more sleep than adults. The old "eight hour rule" does not apply to teens. In fact, the teenage brain needs about nine and a half hours of sleep every night. Are most teenagers getting it? Not by a long shot. Research shows that the average teen gets seven and a half hours of sleep a night, falling two hours short of what they need.

The result: a nation of sleep-deprived adolescents.

As I think back, it is clear that some of the power struggles around sleep that we had with Brian had nothing to do with a bad attitude or poor decision-making. It was what was going on inside his brain.

Tired brains suffer in school

The consequences of chronic sleep deprivation for teens go beyond fatigue. A clinical psychologist at Tel Aviv University, Dr. Avi Sadeh, found a significant performance gap between sleep deprived and well rested students. Students who got just one less hour of sleep per night for three nights in a row experienced a cognitive slide equivalent to two grade levels.

Likewise, a recent study conducted by sleep researcher Dr. Carskadon found that high school students who got poor grades slept an average of 25 minutes less and went to bed 40 minutes later than those who got A’s and B’s.

When it comes to children and sleep, there are huge academic consequences to even small bits of sleep deprivation.

Tired brains suffer in other ways too.

Sleeping teens look so relaxed it is hard to imagine that their brains are hard at work - sifting through the day's learning and memories, solidifying new synapses, retiring weak ones, and solving problems. Brain scans show that the brain is quite active during sleep. Adequate sleep is a core ingredient for learning and memory, mood and emotion regulation, safe driving, and physical health.

It is clear that not getting enough sleep is hard on both the body and the mind.

What can be done?

Just because teens' circadian rhythms change at adolescence, doesn't mean that they need to resign themselves to a decade of fatigue and poor health. Researchers at the University of Minnesota just released a three year study looking at the impact of later school start times on student achievement and health. They found that when high schools switched to a later start time:

  • Attendance, test scores, and academic performance improved;
  • Tardiness, substance abuse, depression, and consumption of caffeinated beverages decreased.

School districts have to make very difficult decisions about start times based on budgets, bussing, sports, and complicated scheduling. I am certainly empathetic to their plight. But from the perspective of brain science, it is clear that teens benefit from the extra hours of sleep.

You can have a big influence on your teen's sleep as well. Here are some ideas for ways to encourage your children and teens alike to get the sleep they need. What would you add to the list?

Sweet dreams,