“The woods are lovely, dark and deep. But I have promises to keep, and miles to go before I sleep”
It’s a common scenario in my house. It’s 1 a.m. and the lights are still glowing from my teenagers’ bedrooms. They are wide awake. But come the next morning, it’s impossible to get them up for school. Did I raise two sloths or am I missing something?
Evolution of sleep
Every living creature needs to sleep. According to www.sleepforkids.org, we spend about 2,920 hours each year sleeping. By the age of 2, children have spent more time asleep than awake. In fact, most kids will spend 40 percent of their childhood asleep.
Many people think sleep is a waste of time. Our eyes are closed, our muscles are relaxed, our breathing is regular, and we don’t respond to sound or light. Think of all the things you could be doing if you didn’t sleep. However, peeking inside the brain during sleep you will find that it’s not a waste of time at all.
So why do we sleep? Why do most animals sleep? How much sleep is required?
Sleep is the primary activity of the brain during early development. The sleep-wake cycle, regulated by light and dark, takes time to develop. This explains the irregular sleep schedules of newborns. The rhythms begin to develop at about 6 weeks, and by 3-6 months most infants have developed a regular sleep-wake cycle.
Purpose of sleep
The sleep foundation (http://sleepfoundation.org) says sleep is food for the brain. No one knows for sure why we sleep but it is thought to be related to two critical functions:
▪ Sleep helps the body recover from all the work it did while awake. The more physical exercise an animal does, the more sleep it demands. Sleep is also thought to be important for memory and learning.
▪ Sleep may have developed in animals as an adaptive process to help protect themselves. It is easier to search for food and water during daylight, while sleeping at night helps prevent getting eaten or falling off a cliff. Animals that sleep the least tend to become food for other animals.
Skipping sleep can be harmful — even deadly. A brain that is hungry for sleep will get it, even when you don’t expect it. Falling asleep at the wheel causes more than 100,000 car crashes every year. Sleep deprivation makes the body more prone to accidents, injury and/or illness.
Types of Sleep
There are two alternating types or states of sleep:
▪ Non-Rapid Eye Movement (NREM) or “quiet” sleep. During the deep states of NREM sleep, blood supply to the muscles is increased, energy is restored, tissue growth and repair occur, and important hormones are released for growth and development.
▪ Rapid Eye Movement (REM) or “active” sleep. During REM sleep, our brains are active and dreaming occurs. Our bodies become immobile; breathing and heart rates are irregular. Infants spend about 50 percent of their sleep time in NREM and 50 percent in REM sleep. Adults spend about 20 percent of their sleep time in REM and 80 percent in NREM sleep. The elderly spend less than 15 percent of their sleep time in REM sleep.
Change in Sleep Patterns
From newborn to 2 months, sleep occurs around the clock, interrupted only by the need to be fed, changed or comforted. They typically sleep 11-18 hours a day.
By 6 months, some infants will begin sleeping through the night. By 9 months of age, 70-80 percent will do so. At this stage, infants typically sleep nine to 12 hours during the night and nap one to four times a day, decreasing as they reach age 1.
Toddlers 1 to 3 years old need about 12-14 hours of sleep every 24 hours. By 18 months of age, naps typically decrease to once a day lasting about one to three hours. Many toddlers resist going to bed and can experience nighttime awakenings due to fears and nightmares.
Preschoolers 3 to 5 years old typically sleep 11-13 hours and may no longer require a nap. As the imagination develops, it is not uncommon for preschoolers to experience nighttime fears or nightmares — these tend to peak during preschool years.
Children 5 to 12 years old need 10-11 hours of sleep. At this age, increasing time demands arise from school and other extracurricular activities. School-aged children become more interested in TV, computers and caffeinated products — all of which can lead to difficulty falling asleep, nightmares and disruptions to their sleep. Sleep disorders are prevalent at this age.
Teens in the U.S. have been found to be chronically sleep-deprived and pathologically sleepy. A National Sleep Foundation poll found 59 percent of 6-8th graders and 87 percent of high school students in the U.S. were getting less than the recommended 8 1/2 to 9 1/2 hours of sleep on school nights.
The reasons for teens’ lack of sleep include homework, extracurricular activities, after-school jobs and use of technology that can keep them up late on weeknights. It is recommended that teens and parents understand the impact of healthy sleep habits, including enforcing a media curfew.
Teens are special
Sleep patterns change as people age. According to Sue Shellenbarger’s Wall Street Journal article “Understanding the Zombie Teen’s Body Clock,” science offers some insight into the exasperation that many parents feel when their teen’s sleep pattern seems to be running amok. It isn’t just sleep patterns that change over time in our children — so do risk-taking, self-control and a seemingly perpetual emotional roller coaster.
Centers for Disease Control (CDC) say that only 7.6 percent of teens get the recommended 9-10 hours of sleep, 23.5 percent get eight hours, 30.2 percent get 7 hours and 38.7 percent are seriously sleep-deprived at six or fewer hours a night.
What happens in the adolescent is equal to a biological 1-2-3 punch. It begins with the onset of puberty, which causes a delay of nearly 1 1/2 hours in the body’s release of the sleep-inducing hormone melatonin. Second, the need to sleep as the day wears on — sleep pressure — tends to drop during adolescence. Teens don’t become sleepy as early as they did when they were younger. Lastly, teens lose some of their sensitivity to morning light and become more reactive to nighttime light.
When coupled with predawn school start times and late night online socialization, all this can affect your child’s health, school performance — and family peace.
Research suggests that sleep loss is linked to decreases in memory, attention and academic performance. Sleep-deprived teens are more likely to feel sad or hopeless, or to seriously consider suicide.
Some parents motivate their teens by reminding them that more sleep helps to keep skin clear and avoid weight gain.
Don’t leave it up to your teen
Sleep researcher and professor Mary Carskadon says allowing teens to manage their own schedules can lead to a downward spiral. Left to their own devices, teens tend to fall asleep later. Soaking up stimulating light from computers can further delay sleep by 2½ to 3 hours. Peer pressure also plays a role. Teens with friends who sleep less than seven hours a night are more likely to sleep less themselves.
Impact of school schedules
Getting enough sleep each night can be challenging for those whose natural sleep cycles make it difficult for them to fall asleep before 11 p.m. and then face a first-period class at 7:30 a.m. Yet more than half of public high schools in the United States start before 8 a.m. Students are in a constant battle with fatigue during class and struggle with homework in the afternoon.
A one-hour delay in middle school start time was linked to a 3 percent increase in math and reading scores, according to a study published by the Economics of Education Review.
In a new policy statement published online Aug. 25, 2014, the American Academy of Pediatrics recommended that middle and high schools delay the start of class to 8:30 a.m. or later. Doing so would align school schedules to the biological sleep rhythms of adolescents, whose sleep-wake cycles begin to shift up to two hours later at the start of puberty. Studies show that delaying early school start times is one key factor that can help adolescents get the sleep they need to grow and learn.
But despite calls from parents or medical professionals, economics like bus-cost savings, or the need to keep afternoons open for after-school sports and activities have caused many schools to reject pressures to delay school start time.
Suggestions for better teen sleep
The Mayo Clinic suggests that teens:
▪ Stick to a schedule. Tough as it might be, encourage your teen to keep weekday and weekend bedtimes and wake times within two hours of each other. Prioritize extracurricular activities and curb late-night social time as needed. If your teen has a job, limit working hours to 16 to 20 hours a week.
▪ Nix long naps. If your teen is drowsy during the day, a 30-minute nap after school might be refreshing. Be cautious, though. Too much daytime shut-eye might make it harder to fall asleep at night.
▪ Curb the caffeine. A jolt of caffeine might help your teen stay awake during class, but the effects are fleeting — and too much caffeine can interfere with a good night’s sleep.
▪ Keep it calm. Encourage your teen to wind down at night with a warm shower, a book or other relaxing activities.
▪ Know when to unplug. Take the TV out of your teen’s room. Minimize use of electronics in the hour before bedtime.
▪ Adjust the lighting. If your teen does use a phone or tablet near bedtime, tell him or her to turn down the brightness and hold the device at least 14 inches away to reduce the risk of sleep disruption. In the morning, expose your teen to bright light.
▪ In some cases, excessive daytime sleepiness can be a sign of a deeper problem and should be addressed by a physician. These may include medication side effects, insomnia, depression, obstructive sleep apnea, narcolepsy, or restless leg syndrome.
Laurie Futterman ARNP is a former heart transplant coordinator at Jackson Memorial Medical Center. She now chairs the science department and teaches gifted middle school science at David Lawrence Jr. K-8 Center. She has three children and lives in North Miami.