3
Inside Sleep: What It Is, How It Works, Why Teens Need It

In the first two chapters, I talked about the many problems that teens who don’t get enough sleep can have: Not only can they stay awake way into the night and drive you to distraction, but they can suffer numerous negative effects on their health, performance, relationships, and well-being. In this chapter I focus on all the good things sleep does and why an adequate amount is necessary for top functioning and quality of life. I also tell you, in the simplest of terms, exactly what goes on during sleep and why every stage is important. Don’t worry, there won’t be a quiz at the end, but the more you understand about sleep, the better you’ll be able to help your teen understand why she should be getting more ZZZZs.

Let’s start by defining sleep. Shakespeare called it the “chief nourisher in life’s feast” and wrote that it “knits up the raveled sleave of care.” The poet John Keats invoked it as “magic sleep” and thought of it like a nesting bird “brooding o’er the troubled sea of the mind till it is hushed and smooth.” The National Sleep Foundation describes sleep as the “key to health, performance, safety, and quality of life.” It’s also the opposite of wakefulness, which is an alert, connected, interactive state of being in which we have control over our movement and thinking. Sleep is a complex process that is all of these things and more.



The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement



Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits 3 Inside Sleep: What It Is, How It Works, Why Teens Need It In the first two chapters, I talked about the many problems that teens who don’t get enough sleep can have: Not only can they stay awake way into the night and drive you to distraction, but they can suffer numerous negative effects on their health, performance, relationships, and well-being. In this chapter I focus on all the good things sleep does and why an adequate amount is necessary for top functioning and quality of life. I also tell you, in the simplest of terms, exactly what goes on during sleep and why every stage is important. Don’t worry, there won’t be a quiz at the end, but the more you understand about sleep, the better you’ll be able to help your teen understand why she should be getting more ZZZZs. Let’s start by defining sleep. Shakespeare called it the “chief nourisher in life’s feast” and wrote that it “knits up the raveled sleave of care.” The poet John Keats invoked it as “magic sleep” and thought of it like a nesting bird “brooding o’er the troubled sea of the mind till it is hushed and smooth.” The National Sleep Foundation describes sleep as the “key to health, performance, safety, and quality of life.” It’s also the opposite of wakefulness, which is an alert, connected, interactive state of being in which we have control over our movement and thinking. Sleep is a complex process that is all of these things and more.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits I define sleep as a multifaceted process that happens every 24 hours and that should last seven to nine hours in adults and as long as nine and a half hours in adolescents. During sleep, consciousness is significantly reduced, we disconnect from our surroundings, and our bodies engage in restorative functions—making proteins, hormones, and neurotransmitters—that enable growth, learning, and mood stabilization. Basically, sleep affects every aspect of functioning. It heals the previous day’s stresses and strains—perhaps a pulled muscle or a cold—and gives us the mental and physical energy we need to function the next day—without being too grouchy. Sleep lets us—more likely, our teens!—run the 50-yard dash in the state track competition and allows us to think clearly and learn figures and facts. Adequate nighttime rest takes a body and mind that are worn out from their day and brings both back to a clean baseline. Although sleep is a time during which we look quiet, there’s actually a great deal of metabolic, or physical and chemical, activity taking place. Much of that activity takes place in the brain. Years ago scientists believed that, because the body looked quiet, the brain was quiet too and was resting like the body. But with the invention of the electroencephalograph, which uses small metal cups glued to the scalp to record microvolts of brain wave, or EEG, activity, scientists learned that the brain, as well as the body, is hard at work while we sleep. Sleep is critical to helping both the mind and the body maintain physical and psychological well-being. But more than 50 million Americans as well as millions of people around the world report difficulty sleeping. That means that many of us, including teens, are not living as well as we could. How much sleep do we need to fuel our potential? I’ve already said that the ideal amount of sleep for adolescents is eight and a half to nine and a half hours. But it’s not much less for adults: seven to nine hours (in my practice I call seven hours the lowest legal limit of sleep). And babies and small children need tons of it. But needing it and getting it are two very different things. The 24/7 society we live in, overloaded with electronic tools and all forms of entertainment, is a major reason we don’t get the sleep we

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits SLEEP NEEDS THROUGHOUT LIFE The National Sleep Foundation recommends the following amounts of sleep for infants, children, teens, and adults. Age Group Hours Newborns   0–2 months 10.5–18   2–12 months 14–15 Children   12–18 months 13–15   18 months–2 years 12–14   3–5 years 11–13 Adolescents 8.5–9.5 Adults 7–9 need (for more on the many cultural factors that promote sleep deprivation in teens, see Chapter 5). Even when we do drag ourselves away from our computers, TVs, and iPods, we often sabotage ourselves with worries and stress that interrupt and/or shorten our nights. Sleep—as it’s meant to be—is a dynamic process composed of five separate stages, each of which is physiologically different and fulfills different body and brain requirements. We need to cycle through all the stages in an orderly sequence during the night and spend adequate time in each, with as few interruptions as possible, in order to reap their full benefits. The Stages of Sleep As I discussed in Chapter 1, sleep-wake homeostasis and the circadian rhythm drive the need for and the timing of sleep. When the hormone melatonin is first secreted in the late afternoon, it signals the brain to begin the process that leads to sleep hours later. SNOOZE NEWS Animals, like people, have different sleep requirements. Giraffes sleep only two hours a night, whereas bats sleep 20. Cats are one of the few animals that don’t group most of their sleep time into one long nighttime session, preferring to sleep for fairly even chunks of time throughout the day—cat naps!

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits HOW DOES YOUR BRAIN KNOW WHEN TO TURN SLEEP ON? Falling asleep depends on several key factors: How many hours you’ve been awake (Process S) The influence of the day-night cycle (Process C) The timing of melatonin secretion Genetics—whether you were born a night owl or a lark Your behavior and the habit you get into Stage 1 I like to call Stage 1 “boring lecture sleep” because it’s the state most of us are in when we’re a bit tired and sitting through a boring lecture: Our eyes close and we hear the speaker droning on only in the distant background. Stage 1 is actually a transitional stage of sleep in which you begin to disconnect from your surroundings and start moving into a nonwakeful state. While you may still feel attached to your environment—you know you’re sitting in a lecture hall listening to a boring speaker—you also may experience a sense of sleepiness or fading. Stage 1 sleep generally lasts about 10 minutes, and you can be awakened from such sleep fairly easily—often accompanied by that embarrassing full-body, falling-off-the-cliff jerk. Many people who wake up from Stage 1 will deny that they were really sleeping, even when you’ve been watching them twitch and snort and breathe more slowly. Brain waves in Stage 1 are characterized by a gradual waning of the 8- to 12-cycles-per-second alpha wave rhythm that is the hallmark of relaxed wakefulness and an increase in slower, four- to seven-per-second theta wave forms that indicate sleep. Slow, horizontal roving-eye movements may be seen during this stage of sleep, and there may also be a regularization of breathing and a slight relaxation of the muscles. During the transition to Stage 1 from wakefulness, some people experience visual misperceptions called hypnogogic, or drowsiness-related, hallucinations. Others experience what they describe as a feeling of falling.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits Stage 2 In Stage 2 there is a further increase in slower, relatively low-voltage, mixed-frequency theta wave activity. There are also two sleep phenomena: sleep spindles, which are runs of highly rhythmical activity predominantly in the central regions of the head that last from one-half to one and one-half seconds; and K complexes, which are distinctive high-voltage complex wave forms that are thought to be a protective response to arousal and that promote the transition to deeper stages of sleep. While the exact purpose of Stage 2 sleep is unknown, it seems to be a stage that prepares the body to head into deeper sleep, though you definitely feel you’ve been asleep if you’re awakened from this stage. Stage 2 accounts for 45 to 55 percent of our night’s sleep. Stages 3 and 4 In Stage 3 and Stage 4 sleep, or slow wave sleep (SWS), brain activity slows dramatically and the mixed-frequency theta activity of Stages 1 and 2 is replaced by one- to three-per-second slow waves. The distinction between Stages 3 and 4 is only in degree: When more than 20 percent of any 30-second period of sleep is composed of high-voltage slow waves, it is called Stage 3. The period is considered Stage 4 if more than 50 percent of it is composed of these waves. In Stages 3 and 4, sleep spindles are less prominent and K complexes drop out. During both stages, breathing is deep and regular, muscles relax, blood pressure drops, and eye movement generally stops. Both stages are also a very deep period of sleep from which it’s difficult to be awakened; you may have tried to wake your teen as a child and gotten scared because she seemed unconscious. Dreaming can occur during slow wave sleep, although most dreaming takes place during the fifth stage of sleep. SWS constitutes about 20 percent of your night’s sleep. During this period, growth hormone is secreted, muscles rest and receive an increased supply of blood, the immune system is active, and tissue growth and repair take place. Energy is restored and, if we get enough SWS, we wake feeling great and physically ready to face the day. But if we don’t, we can feel not just tired but achy and disoriented.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits The five stages of the sleep-wake cycle are distinct with different patterns of brain wave activity (EEG), eye movements, and muscle tone (chin). In Stage 4 SWS, the arousal threshold is very high. But if you’re awakened abruptly, you may experience “parasomnias” such as sleep walking, sleep talking, or night terrors (episodes of screaming and agitation during the first half of the night). All of these phenomena occur between sleep and wakefulness—you aren’t fully awake but you also aren’t fully asleep, and you usually transition back to sleep without waking up. Parasomnias are considered to be normal occurrences and happen more frequently in childhood and adolescence than in adulthood.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits Stage 5 This stage of sleep wasn’t clearly described and understood until the early 1950s. It’s a very different type of sleep from the other four because in those stages there’s little or no eye movement; Stage 5 features bursts of rapid side-to-side eye movement under our eyelids. That darting movement gives the stage its name: REM, or rapid eye movement, sleep. The first four stages of sleep are often referred to together as NREM, or non-rapid eye movement, sleep. SLEEP-RELATED DISCOVERIES With the invention of the electroencephalogram and the discovery of all five stages of sleep, sleep researcher J. Allan Hobson noted that “more has been learned about sleep in the past 60 years than in the preceding 6,000.” Yet there is still much to learn and understand today. REM sleep accounts for nearly one-quarter of our total sleep time. We cycle into it approximately every 90 minutes but the first episodes are short and those later in the night are much longer. In REM sleep, as in SWS, it’s very hard to wake up. It’s also a time of intense dreaming, and the dreams may have strange spatial relationships, colors, and ideas. Bizarre emotions may surface in frightening dreams, but the majority of REM-related dreams are usually pleasant. It is during REM sleep that the psyche is restored, and recent evidence shows that REM sleep is also involved in the processing of information (see Chapter 4 for more on the sleep-learning link). During REM sleep we breathe faster, our heartbeat is more irregular, and speeded-up brain wave activity makes it look like we’re awake. A key feature of REM sleep is that, except for the bursts of rapid eye movement and synchronous activity in the inner ear, no other parts of our bodies can move—our muscles are paralyzed. If you’ve ever had a dream in which you tried to run away from the bogeyman or wanted to speak or scream but couldn’t, you were having a REM dream and the paralysis of your body was incorporated into your dream. Why can’t you move during REM sleep? We believe the paralysis

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits of REM sleep is a protective reflex. During this sleep, we’re not conscious of the outside world, and current theories suggest that our brains are rehashing all the information received during the day, as well as analyzing memories and forming brand new ones. During this work, frightening or dangerous thoughts can occur, and the paralysis of our muscles prevents us from acting on those thoughts and dreams. People with a condition called REM Sleep Behavioral Disorder, which interferes with REM paralysis, can respond to a dream with dangerous movement. For example, if they’re having a dream in which someone is chasing them, they can jump out of bed and start running away—and crash into a bedside table or fall. If they’re dreaming that they’re in a fight with someone, they can punch or kick the person sleeping next to them. If we were able to move during REM sleep and act on our dreams, we could end up in the hospital—or always have to sleep alone. SNOOZE NEWS Because REM sleep combines a very active brain with a paralyzed body, it is sometimes called paradoxical sleep. REM sleep appears to be particularly important to the developing child and adolescent. Studies on the effects of sleep deprivation suggest that REM sleep deprivation in newborns can negatively affect central nervous system development, and permanent sleep disruption early in life can cause an abnormal number of neural cells to die. REM sleep is also crucial for the anabolic, or energy building and healing, activities that take place in the brain and in the body. The Cycles of Sleep Once you’ve snoozed your way from boring-lecture sleep through REM sleep, you’re said to have completed one cycle of sleep. A full cycle takes approximately 90 to 120 minutes, so if you get all the rest you need, you’ll go through four or five cycles each night. But on the second through the fourth or fifth cycles, things change a bit. After you complete REM sleep, you may only briefly pass through boring-lecture sleep or skip it entirely before moving into Stage 2 and then completing the stages through Stage 5 again. The time you spend in each stage also changes; the first half of the night is spent mostly in

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits Sleep hypnogram illustrating how the average teen cycles through the five stages of sleep during the course of the night. SWS and the second half mostly in REM sleep. By sleeping uninterrupted through all of the stages, while in tune with the day-night cycle, you give your body and mind the time they need to heal the previous day’s wear and tear and reenergize for the day ahead. The Times They Are A-Changin’ Although it’s clear that people of all ages need to get regular, adequate amounts of sleep if they want to function at their best, today’s homo sapiens sleep much less than their predecessors did and their sleep patterns are often irregular and interrupted. In the agrarian society of our not-too-distant past, sleep was much easier to come by. There was no electricity, so there was no TV to watch, no telephone to gab on, no computer for playing games, no CDs to listen to. In the evenings families could, of course, sit around the piano and sing or read or talk by candlelight, but most of today’s distractions weren’t available then, which made going to bed not long after dark much more likely. And, of course there were the cows—which made getting up at a reasonable time also more likely. Milking, feeding animals, and starting to work in the fields before the extreme heat of midday made waking and rising with the sun not just natural but a necessity. Most people were entrained to the day-night cycle, and most found that the hard physical labor that filled their days caused them to sleep an average of

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits Limited activities and distractions along with a more physically active lifestyle allowed more time for sleep in 1905 compared to 2005. 10 hours a night, healing their bodies and getting them ready for the next challenging day. Today, of course, we sleep much less. As the chart on page 49 shows, seven to nine hours of sleep is considered adequate for adults, and many of us don’t get anywhere near that amount. The same definitely goes for teens. On average, we’re sleeping an hour and a half less a night than we did at the beginning of the 20th century, a truly shocking reduction. Yet at the same time that we’re sleeping much less, we’re asking much more of our bodies and minds. Today people are making demands on themselves as they never have before. If you think about how humans and animals have evolved, you’ll remember that it takes centuries for new capabilities to develop. But the digital age has pushed us to become more capable more quickly, and with that intense push has come a huge increase in the demand for alertness. We need to stay awake and functioning if we’re

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits going to survive in our constantly connected, constantly advancing culture. Just think of all the devices that you—and your teen—live with every minute of the day—as well as during the night. Is that a pager I see on your belt? Is there a cell phone in your bag? When did you last check your e-mail? Is that a fax I hear coming in from across the ocean—at 3:30 a.m. your time? The need to “stay in the game” has pushed us to expect much more from our bodies. But we are expecting those bodies to keep up on less sleep and therefore less time for repair and renewal—which makes us unable to evolve in tandem with our environment. That may spell disaster not just for us but for our children, because one of the ways humans evolve is through natural selection—the process through which the organisms that are best suited to their environment survive and pass their genetic material on to the next generation. By raising sleep-deprived teens, we may be putting them at greater risk for long-term disease complications; we know that sleep deprivation weakens the immune system. But until more studies are done, we won’t know if sleep deprivation during the teen years has more farreaching implications on adult health and longevity. We do know that teens today, just like adults, are much more sleep deprived than they used to be. A study by Roseanne Armitage reported that 24 percent of college students in 1978 complained of being constantly tired; in 2002 that number exploded to 71 percent. We also know that negative impacts result not just from sleepiness but from sustained wakefulness—our bodies just can’t operate at full tilt when we push ourselves to stay awake for more than 15 or 16 hours. Teens, of course, are in touch with their friends, as well as the rest of the universe, for more than 16 hours a day. My latest reminder of that fact came on a recent trip with my daughter Elyssa to tour several colleges. After getting completely lost looking for our motel the first night, I staggered into bed in our shared room and she eventually followed. But at 1:00 a.m. her cell phone rang—and she answered it! After talking to her friend for a few minutes, she headed back to sleep, and I tried to do the same. But at 2:30 the phone rang again! This time Elyssa slept right through the ring—but I bet you can guess who didn’t. Our 24/7 society is wreaking havoc with our natural rhythms and

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits needs. While we still have the reflex that makes us feel sleepy, we don’t still have the reflex that makes us stop what we’re doing and go to sleep—we’ve found untold ways to override it. Over the years we’ve stretched and stretched our daytime alert hours until, for many of us, including our teens, night and day have become pretty much the same. WHEN NIGHT BECOMES DAY As we become more and more sleep deprived, “state instability” develops: Our state of wakefulness destabilizes, we can’t remain alert, and there’s a blurring of the boundaries between wakefulness and sleep. When that happens we’re subject to: Microsleeps—very brief stretches of sleep interrupting our consciousness; microsleeps cause us to miss hearing bits of information Sleep attacks—periods of sleep that occur inadvertently and often without warning Lapses in cognition—periods of mental fogginess during which we have timeouts in function that can last up to 18 seconds The Gene Factor Don’t most kids love to blame things on their parents? Well, here’s their chance to do it again—but this time with some cause. Unfortunately, for long-suffering parents everywhere, having trouble falling asleep before midnight might not be due only to pubertal, environmental, or cultural factors. It might also be something that teens can actually hold their parents accountable for. Clearly some adults find it easier to stay up later than others. These night owls are alert and energized far later in the evening than most of us, and they have a good deal of difficulty getting up in the morning for work or school. Though they’re past the age when their brains are wired to cause this late-to-bed, late-to-rise syndrome, their natural body rhythm is to go to sleep later and wake up later—they still have a sleep phase delay. Often adult night owls are tired all morning and afternoon and then begin to come into their own as everyone else is winding down.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits Now here’s the blame part. Just the way brown eyes, full cheeks, and the ability (or inability) to understand math can be passed from mother or father to son or daughter, the tendency to be a “night person” can be handed down to children; if a parent is a night owl, there’s a significant chance that her child will be one too. DR1 markers, one group of human leukocyte antigens, which are markers in the white blood cells that help identify a variety of conditions, including whether or not a person is a good bone marrow donor, were positive in a statistically significant number of people who were sleep phase delayed. That suggested to the researchers conducting the study that there is a genetic predisposition to Delayed Sleep Phase Syndrome. A TEEN’S TAKE “My dad is definitely not a night owl. He falls asleep five minutes after he turns on the TV or lies down. My mom, though, is a different story. She doesn’t go to sleep until after I do, and I’m up till at least 11:00. Then it takes me some time to fall asleep.” Often when young patients come in to see me because they can’t fall asleep before 1:00 or 2:00 in the morning, it turns out that one or both parents have the same problem. These adults may have found a way to live with the situation, perhaps by working in a job that doesn’t require an early start or by running their own business and setting their own hours, but their teens generally are not as lucky; they don’t have the lifestyle choices that adults do. A friend of mine, for example, really wanted to have a third child but knew from her experiences waking up to nurse her first two children several times a night that she couldn’t tolerate months and months of interrupted sleep and sleep deprivation again—it made her completely incapable of functioning, both at home and at work. So she made the choice to have another baby, but to provide a college student with room and board in exchange for getting up in the night to give the baby her bottles. My friend knew her limits and had the freedom and the wherewithal to come up with a workable solution for her problem. When a teen night owl comes to see me and we determine that she is from a night-owl family, I generally am more aggressive and try to

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits SNOOZE NEWS While some people can’t handle sleep loss at all, others have been found to tolerate it much better. We don’t yet know the molecular protective factor that’s involved, but researchers are trying to uncover it. engage the entire household in the treatment plan. That’s because it’s particularly tough to change a teenager’s wake-up time if no one else in the family is getting up in the morning and the household culture is to stay up late. It’s definitely harder to change a teen’s sleep pattern when not only puberty is involved but genetics as well. This double whammy can take time to turn around. (If you or your spouse is a night owl, see Chapter 12 for ideas on how you can set a good sleep model for your teen.) To add to the bank of potentially inheritable sleep problems, cutting-edge studies have shown that there may be a genetic link to the length of time a person sleeps. If one parent is a “short sleeper”—he or she naturally goes to sleep late and wakes up early—the child will be predisposed to be a short sleeper too. An Important Period for Sleep While getting enough high-quality sleep at any age is crucial, it’s particularly important for adolescents. Not only do they need it for all the growing and changing and learning they must accomplish, and to function at their best, but they need to establish a healthy sleep habit for all the years ahead. Teens who stay up well into the night and are exhausted all day can let an age-related problem turn into a life-long pattern of living. As teens make the transition from child to adult, they can add greatly to their chances of enjoying a healthy future if they start following a healthy sleep pattern.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits SLEEP FOR TEENS IQ TEST Ask your teen to take this National Sleep Foundation quiz to check her understanding of what happens during sleep and why she needs more sleep than she’s getting. It’s a good idea for you and the rest of your family to take the test too. During sleep, your brain rests. (T or F) You can learn to function normally with two or three hours less sleep than your body actually needs per night. (T or F) Teens go to sleep and wake later because they are lazy. (T or F) Although you may not get enough sleep during the week, you can catch up on your sleep on weekends and still have healthy sleep habits. (T or F) Boredom makes you feel sleepy, even if you have had enough sleep. (T or F) Resting in bed with your eyes closed cannot satisfy your body’s need for sleep. (T or F) Snoring is not harmful as long as it does not disturb others or wake you up.* (T or F) Most people do not know when they are sleepy. (T or F) Turning up the radio, opening the window, or turning on the air conditioner will help you stay awake while driving. (T or F) Sleep disorders are mainly due to worry or psychological problems. (T or F) Everyone dreams every night. (T or F) Driving after being awake for 18 hours puts you at the same level of risk for a crash as someone who is legally drunk. (T or F) Answers: 1. F, 2. F, 3. F, 4. F, 5. F, 6. T, 7. F, 8. T, 9. F, 10. F, 11. T, 12. T    * Snoring may be a sign of sleep apnea; see Chapter 7 for details.

OCR for page 47
Snooze…Or Lose!: 10 “No-War” Ways to Improve Your Teen’s Sleep Habits This page intially left blank