Sometimes this is attributed to laziness in adolescents. But the main reason a healthy person is unable to wake up naturally without an alarm is because they’re not getting the sleep their brain and body need.
In fact, studies show that teenagers need more than nine hours of sleep a day to be physically and mentally healthy.
But the chances of you knowing a teenager who gets enough sleep is pretty slim. In the United States, less than 30% of high school students — or those in grades 9 through 12 — get the recommended amount of sleep, according to the Centers for Disease Control and Prevention. Among middle school students in grades 6-8, almost 60% don’t get enough sleep at night.
Yet research from my lab suggests that a much higher percentage of adolescents are getting too little sleep.
I am a professor of biology and have studied sleep and circadian rhythms for over 30 years. For the past seven years, my lab at the University of Washington has been researching sleep among Seattle-area adolescents. Our research revealed that, just like in other parts of the United States, high school students in Seattle don’t get enough sleep. Our study objectively measured the sleep of 182 sophomores and high school seniors and found only two who slept at least nine hours a night during school days.
Our studies and those of others indicate that three important factors are driving this epidemic of sleep deprivation: physiological regulation of sleep that leads to misaligned sleep time in adolescents and is not aligned on early school hours, a lack of exposure to daylight, and excessive exposure to bright electric light and screens late at night.
Biology of sleep in adolescents
The times people go to bed, fall asleep and wake up are governed by two main factors in the brain. The first is a so-called “wake tracker,” a physiological timer that increases our need to sleep the longer we stay awake. This is partly the consequence of the accumulation of chemical signals emitted by neurons, such as adenosine.
Adenosine builds up in the brain when we are awake, leading to increased sleepiness as the day progresses. If, for example, a person wakes up at 7 a.m., these chemical signals will build up throughout the day until levels are high enough for the person to fall asleep, usually late in the evening. .
The second factor that governs the sleep/wake cycle is a 24-hour biological clock that tells our brain what times of day to be awake and what times to sleep. This biological clock is located in an area of the brain called the hypothalamus. The clock is made up of neurons that coordinate areas of the brain that regulate sleep and wakefulness in a 24-hour sleep/wake cycle.
These two regulators operate with relative independence from each other. But under typical conditions, they are coordinated so that a person with access to an electric light will fall asleep in the late evening, between about 10 p.m. and 11 p.m., and wake up early in the morning, around 6 a.m. 7 a.m.
So why do teenagers often want to go to bed later and wake up later than their parents?
It turns out that during adolescence, wakefulness tracking and the biological clock conspire to delay the timing of sleep. First, teens can stay awake until hours later before their wake tracker makes them sleepy enough to fall asleep.
Second, the biological clock of adolescents is delayed because in some cases it seems to be running at a slower rate and because it reacts differently to light signals that reset the clock daily. This combination leads to a sleep cycle that runs a few hours later than in an older person – if an older person gets the cue to fall asleep around 10 p.m. or 11 p.m., it won’t happen until midnight or later in a teenager.
How Back-to-School Hours Help
To help find more hours of sleep for teens, one step some school districts across the country have taken is to delay the start of school time in middle and high schools. The American Academy of Pediatrics recommends that schools for this age group start no earlier than 8:30 a.m. Yet the majority of high schools in the United States start at 8 a.m. or earlier.
Based on the recommendation of sleep experts, the Seattle School District, beginning with the 2016-2017 school year, delayed middle and high school start times by nearly an hour, from 7:50 a.m. to 8:45 a.m. In a study our team conducted after the district enacted the plan, we found that students gained 34 minutes of daily sleep, a huge gain by sleep medicine standards. In addition, student attendance and punctuality improved and median grades increased by 4.5%.
Despite an abundance of research evidence and the advice of virtually every sleep expert nationwide, most school districts are still stuck with school start times that promote chronic sleep deprivation in teens. Early school starts are further aggravated by daylight saving time, when clocks are put forward an hour in the spring. This jet lag – which could become permanent in the United States in 2023 – exposes teenagers to artificially dark mornings, which exacerbates their naturally delayed sleep schedule.
Teaching Teens Healthy Sleep Habits
Aside from back-to-school hours, children also need to learn the importance of healthy habits that promote adequate sleep.
Exposure to daylight, especially in the morning, pushes our biological clock back to an earlier time. This, in turn, will promote an earlier bedtime and a natural early morning wake-up time.
In contrast, evening light, including the light emitted by screens, is very stimulating for the brain. It inhibits the production of natural signals such as melatonin, a hormone produced by the brain’s pineal gland at the onset of night and in response to darkness. But when these signals are inhibited by artificial light in the evening, our biological clocks are delayed, promoting a later bedtime and a later morning awakening. And so the cycle of having to kick a sleeping, yawning teenager out of bed to go to school begins again.
Yet few schools teach the importance of good daily routines and a good sleep schedule, nor do parents and teens fully appreciate their importance. Chronic sleep deprivation disrupts all physiological processes in the body and has been consistently linked to illnesses including depression and anxiety, obesity, and addictive behaviors.
Conversely, getting enough sleep not only helps reduce physical ailments and improves mental health, but has also been shown to be fundamental for optimal physical and mental performance.
This article is republished from The Conversation under a Creative Commons license. Read the original article.