Sleep! The great mystery is only now beginning to slowly reveal its secrets as researchers build on the tiny base that existed at the beginning of the Twentieth Century. Though we have a long way to go, enough is now known to make a real difference in many people's lives.

A valuable resource is examined in this chapter:

THE PROMISE OF SLEEP, William C. Dement, Delacorte Press, New York, 1999.

Get a copy and read it carefully. It might save your life or the life of a friend or loved one.

Dement begins his book this way: (p. 1 ff) "Just a few months ago a colleague of mine had the good fortune of being able to save her nephew's life. Adam was only 12 months old, but it was clear that something was terribly wrong with him. While other kids his age were beginning to walk and talk, Adam couldn't even crawl. His weight and height were far below the norm for his age. He was a tiny, sad, emaciated specter. Every single day of the year, Adam's parents held him and hovered over him, frustrated, heartbroken, frantic with worry. Did Adam have cancer? Some awful birth defect? No. After tens of thousands of dollars' worth of medical testing, their child had been categorized only as having 'failure to thrive.' This is actually a nondiagnosis -- medical throwing up of the hands that meant his doctors had no idea what was wrong. The small army of pediatricians who saw Adam could only say that this baby might waste away and die, or might never be normal if he did survive.

During a visit to her sister's house, my colleague observed Adam while he slept. Being knowledgeable about sleep disorders, she realized right away that the boy could not breathe when he was asleep. His disorder, well known to sleep specialists, was, in this instance, caused mainly by large tonsils and adenoids. His tiny air passages, barely adequate while he was awake, were completely closed off during sleep. A moment after falling asleep he would stop breathing, and within a minute Adam's oxygen-starved brain would wake him up. After taking a few breaths he would fall asleep again and repeat the cycle."

"The sleep specialist's diagnosis was passed on to Adam's pediatrician, who still could not be persuaded to have the boy's tonsils and adenoids taken out. When the procedure was finally performed by another, more enlightened doctor found by the family, the thin and weak little boy underwent a dramatic change. Within a few weeks he was clearly thriving physically and mentally."

"Today, as I write, six months have passed, and this previously despairing family is living with a miracle. Their little boy is taking his first steps, he can crawl everywhere, he is beginning to talk, and he is gaining a pound a month. Sadly, the first terrible year of Adam's life may have lasting effects on his development, but at the moment there is too much relief and happiness to dwell on that."

(p. 2) "When I first entered medical school in 1951, sleep was little more than a curiosity to the scientific world, and it was almost totally ignored in medical practice. Over the ensuing decades, we have learned an enormous amount about the nocturnal third of our lives. Today sleep science is exciting and diversified, utilizing all the tools of modern molecular biology and addressing great scientific questions. Sleep medicine, which I started at Stanford University, where several passionately committed colleagues and I struggled to nurture it through its first uncertain and difficult years, has grown into a mature clinical discipline with stunning skilled practioners able to diagnose and treat a huge array of disorders.

"Unfortunately, doctors and the general public know almost nothing of this vast store of knowledge."

(p. 3) "Hundreds of thousands of people worldwide are dying each year in large part because of undiagnosed and untreated sleep problems -- tens of thousands in the United States alone. For instance, if someone you know has had a heart attack, there is a good chance (especially if the victim is young) that an undiagnosed sleep disorder contributed to the problem."

"Less dramatic than medical tragedy, but nearly as sad, are the people all around us who are fatigued and exhausted every day because they don't understand how to manage their sleep, betrayed by their ignorance about the mechanics of sleep debt and the intricate biological clock that ticks away inside us. Consider these statistics: Half of us mismanage our sleep to the point where it negatively affects our health and safety."

It may seem impossible that people can be very sleepy and not know it, but this fact has been proven beyond the shadow of a doubt. Study after study has revealed that people who are chronically sleep deprived can be completely unaware of the root cause of their overwhelming fatigue."

(p. 4) "In a recent survey by the National Sleep Foundation, 23 percent of the people who were polled admitted falling asleep while driving in the past year. With this in mind, it should be no surprise that sleep deprivation plays a major role in most accidents labeled 'cause unknown,' or that an estimated 24,000 people die each year in accidents caused directly or in part by falling asleep at the wheel."

"Changing the way society and its institutions deal with sleep will do more good than almost anything else I can conceive, or certainly anything that was ever remotely within my grasp to accomplish."

"For a number of years, I helped lobby the U.S. Congress at least to take a look at the problem. It responded in 1990 by creating the National Commission on Sleep Disorders Research, of which I was named chair. When we fulfilled our mandate to study and make recommendations about sleep disorders in the United States, the commission estimated the financial cost of sleep disorders at tens of billions of dollars per year. The human costs, of course, are incalculable."

(p. 6) "When I decided that I would do whatever I could to educate primary care physicians, it occurred to me that the very best place to launch the crusade to change the way society deals with sleep would be in my own hometown, Walla Walla, Washington."

(p. 7) "In what has come to be known as the Walla Walla Project I set out to educate and train Walla Walla doctors in the basics of sleep medicine and to see what impact that knowledge had on their practices and patients."

"Since it was the first time anything like it had been attempted, the Walla Walla Project began slowly. However, from today's perspective, the results of this project have been astounding. The Walla Walla physicians were amazed by the large number of patients they found to have serious sleep disorders. All of these patients had been seen at the clinic on multiple occasions previously, yet their sleep disorders were not recognized until the Walla Walla Project was well under way."

"There is one thing I must make absolutely sure that everyone understands. Primary care physicians are absolutely not responsible for the neglect of sleep disorders in America today. They are as much the victims of the lack of medical school teaching as everyone else."

(p. 9) ...[M]y goal [in this book] is to give people the fundamental knowledge they need to change the way they sleep and live. What I am trying to do is akin to teaching the alphabet of sleep so that people can start learning to read."

(p. 14) "Sleep is a miraculous journey made all the more extraordinary by this one simple fact: We never know we're sleeping while we're asleep. It is impossible to have conscious, experiential knowledge of nondreaming sleep; indeed, one of sleep's defining aspects is that we don't know that we are sleeping while we are doing it. Limited to an abstract knowledge of sleep, we are less able to identify any problems we have while sleeping. Sleep is a perceptual hole in time."

(p. 15) "The moment of sleep is when the brain flips a switch and [instantaneously] isolates itself from the outer world."

(p. 16) Sleep is not the "cessation of all activity, an oblivion we slip into where nothing happens."

"The truth is completely the opposite. As the muscles relax, the mind shifts, and the brain starts behaving differently. During sleep the brain relaxes new combinations of the hormones and chemical messengers that stimulate cellular activity throughout the body. At some times the sleeping brain actually appears to be more active than it is while awake, burning large quantities of sugar and oxygen as neurons fire rapidly. When dreaming, the mind takes on a different consciousness, inhabits a new world that is as real as the world it experiences when awake."

(p. 17) What is sleep? "I define sleep in terms of only two essential features. The first, and by far the most important, is that sleep erects a perceptual wall between the conscious mind and the outside world.... The second defining feature of normal sleep is that it is immediately reversible."

"These two essential features distinguish sleep from other apparently sleeplike states.... two more important qualities of sleep: It occurs naturally, unlike coma, anesthesia, or hypnosis, which require injury, drugs, or some other outside influence; and it occurs periodically -- daily in humans...."

(p. 18) "Sleep also is characterized by electrical change in the brain, which...can [be measured by] electroencephalographs (EEGs).... The ability to chart the brain's activity with EEGs changed the essential nature of sleep research. This made it possible to go beyond the observations of philosophers and poets, to peek at the inner workings of the sleeping brain. In the sleep lab, we now attach electrodes to a person's scalp so that brain activity appears as squiggly lines on a moving sheet of paper produced by a machine call a polygraph."

(p. 19) Beta waves: rapid, low-voltage type.
Alpha waves: slower, higher-strength type.
Theta waves: even lower-frequency type.

"At the moment when the alpha waves of drowsiness yield to the theta waves of stage 1 sleep, a sensory curtain drops and isolates [the] mind from the outside world."

(p. 20) "Stage 1 sleep is light sleep:" A nudge or the sound of a cat screeching might rouse one. If awakened they might say they had not been asleep. Eyes are engaged in slow back-and-forth movements.

Stage 2 sleep: "Readily identified by two new types of sleep-specific brain waves, called sleep spindles and K-complexes, both of which are episodic and last only two to three seconds. A sleep spindle is a short burst of waves with a frequency two to three times that of the background theta waves. On the EEG, it looks a little like the spindle on an old spinning wheel. K-complexes are large waves that usually seem to come out of nowhere and disappear, like a little earthquake on a seismograph. These two wave forms are thought to reflect the massive changes in how sensory information is processed in the brain."

Stage 3 sleep: "The first stage of what is called deep sleep. This stage is heralded by the appearance of the final species of brain wave, the delta wave.... delta waves are like the great ocean swells: larger, more regular, and with a lower frequency. Theta waves, sleep spindles, and K-complexes are still present in stage 3 sleep, but like the wind-blown waves running over ocean swells, they are harder to see."

(p. 21) Stage 4 sleep: "The deepest stage of sleep...which is sometimes called slow-wave sleep." Characterized by delta waves exclusively. Difficult to wake up. Heart and breathing are regular and relatively slow. Muscles are almost completely relaxed."

During the first deep sleep of the night, the body secretes a pulse of growth hormone. During this stage of sleep the hormone prolactin is also released.

After a varying period of deep sleep the body returns to stage 3 sleep, and soon goes into REM sleep (Rapid Eye Movement sleep). "All voluntary muscles become completely paralyzed, and brain activity increases greatly. This is the dream state.... The delta waves have disappeared and the choppy theta waves are back, but now there are also short bursts of alpha and beta waves that on their own characterize wakefulness." There are four to six of these stages of REM sleep with dreams, alternating with non-REM sleep.

(p. 22) "During the early morning hours, levels of a hormone called cortisol start rising.... Cortisol is released during times of stress, but its main job now is to mobilize energy stores, preparing the body for the demands of the coming day. It reaches its peak right before...[one] awakes."

(p. 28) How I became a sleep researcher: Because of an interest in consciousness, I got interested in sleep (absence of consciousness). "...pure chance had delivered me from Walla Walla, Washington, to the doorstep of the only man in the world whose entire professional life was devoted to the study of sleep, and then having read his book [SLEEP AND WAKEFULNESS, 1939], I may have known more about the field at that moment than anyone else but [Nathaniel] Kleitman himself."

(p. 30) "It wasn't until the middle of the twentieth century that sleep scientists found evidence that sleep is not something that just happens to us but that the brain puts itself to sleep. Until then the idea of passive brain seemed intuitively correct."

"Research on sleep entered a new era in 1952, and in the intervening years we have learned more about sleep than in all prior history.

"What I regard as the watershed series of technological advances that were necessary for the dawn of sleep science were, first, the discovery of spontaneous electrical activity in the brains of animals by Richard Coton in 1875, and next the demonstration by German psychiatrist Hans Berger in the late 1920s and early 1930s that the brain of human beings also showed spontaneous electrical activity that could be recorded from the scalp."

(p. 31) "Nathaniel Kleitman, the man who would later be my professor and mentor, was the first to devote the bulk of his entire professional life to the study of sleep. Kleitman was born in Russia but.... [came to the U.S. and] earned his doctoral degree in physiology and became a professor at the University of Chicago, where he set up a laboratory to study sleep in the early 1920s. Until then the study of sleep was a huge blind spot in the science of physiology; no one had made a career out its study. Kleitman was the first in the world to set up a laboratory permanently devoted to the study of sleep."

(p. 34) "When I joined Kleitman's lab...[in the fall or 1952], [Gene] Aserinsly [a graduate student in physiology] had only recently observed 'rapid eye movements,' and was conducting additional studies."

(p. 35) "Aserinsky told me about what he had been seeing in the sleep lab and then threw in the kicker that really hooked me: 'Dr. Kleitman and I think that these eye movements, might be related to dreaming.' For a student interested in psychiatry, this offhand comment was more stunning that if he had just offered me a winning lottery ticket."

(p. 36) "In order to understand why dreams were so interesting to aspiring psychoanalysts of my day, it is important to understand a little about the man who changed the very way we thought abut dreams and who so thoroughly dominated American psychiatry even long after his death. Sigmund Freud, a turn-of-the-century Viennese doctor, is often identified as the 'discoverer' of the unconscious -- the mass of the most primitive instinctual drives, impulses, desires, and feelings that are not illuminated by the spotlight of conscious thought. Freud postulated that during most of our waking moments we deal with these 'unthinkable' desires and impulses by repressing them. Ultimately these thoughts must come out, said Freud, which they did through dreams. In his 1905 book THE INTERPRETATION OF DREAMS, Freud proposed that dreams disguise forbidden thoughts or desires by cloaking them in other forms. The fantastical quality of dreams also works to protect sleep, since dreaming the forbidden in a straightforward way might shock us awake. Dreams therefore represent 'the royal road to a knowledge of the part the unconscious plays in mental life,' wrote Freud. To discover what these repressed thoughts or feeling represent, a psychoanalyst must decipher the dream symbols and events."

"So you can see why, when Gene Aserinsky told me, the aspiring psychoanalyst, 'We think these rapid eye movements might be related to dreaming,' I was doubly blessed. Not only would I get the chance to look into the nature of consciousness, I would be studying the very root of unconscious motivation in dreams. The study of dreams was far from the world of 'real' physiological research for Aserinsky, who was perfectly content to allow someone else to continue down this particular road."

"One of my first assignments was to awaken people during the night and ask them if they remembered dreaming."

(p. 37-38) "I believe that the study of sleep became a true scientific field in 1953, when I finally was able to make all-night, continuous recordings of brain and eye activity during sleep.... After carrying out all-night recordings in a large number of individuals, I began to become convinced that periods of rapid eye movement were part of a 90-minute basic sleep cycle. Everybody, without exception, had the same pattern of sleep. This was a major discovery. In some cases, the eight-hour pattern from one night's recording could be superimposed almost perfectly on the pattern of another night."

"Two other amazing observations awaited me in these all-night recordings: There were distinct stages of sleep during the night, which I called stage 1, stage 2, stage 3, and stage 4 sleep. Furthermore, I observed that rapid eye movements did not take place during any of these stages, but constituted a fifth distinct stage, which I called REM sleep."

(p. 39) "Everywhere I looked, I found this intriguing sleep state. Even people who are blind from birth experience REM sleep, though the contents of their dreams does not contain visual images.... rapid eye movements [occur]...during sleep of newborn infants."

(p. 40) "I obtained my M.D. in 1955.... [and] my Ph.D. in 1957...."

"...I found that during REM the brain acts as if it were awake, even though the rest of the body lies still."

(p. 42) "Even though everyone thinks of sleep as one thing, REM and non-REM are as different from one another as both are from wakefulness."

(p. 43-44) "...[T]he brain values REM sleep on its own. When the brain is deprived of REM periods, it tries to compensate by having longer REM periods and having them sooner.... by the third or fourth night, REM pressure would increase to the point where the REM periods would start right after the subject fell asleep."

"After I moved to Stanford University in 1962, I continued studies of REM deprivation in both humans and cats."

"We have never found conclusive evidence that depriving people of dreams causes mental illness. Although dreams may play some part in keeping our mental equilibrium, and sleep itself indisputably does so, we realized we would have to look elsewhere for the source of the kind of mental illness that Freud studied."

(p. 47) In 1970 I opened the Stanford Sleep Center as a general sleep disorders clinic.

(p. 51) "The night of March 24, 1989, was cold and calm, the air crystalline, as the giant Exxon Valdez oil tanker pulled out of Valdez, Alaska, into the tranquil waters of Prince Williams Sound.... The huge tanker ran aground spilling millions of gallons of crude oil into the sound. The cost of the cleanup effort was over $2 billion.... when the civil trial was finally over in this summer of 1995, the Exxon Corporation was assessed an additional $5 billion in punitive damages.... In its final report, the National Transportation Safety Board (NTSB) found that sleep deprivation and sleep debt were direct causes of the accident."

(p. 52) "The Exxon Valdez disaster offers a good example of how sleep debt can create a tragedy and how the true villain -- sleep indebtedness -- can create a tragedy and how the true villain -- sleep indebtedness -- remains concealed.... the third mate [pilot of the ship at the time of the accident]...had slept only 6 hours in the previous 48 and was severely sleep deprived."

(p. 53) "An even more dramatic tragedy was the explosion of the space shuttle Challenger. After a year-long investigation, the Rogers Commission declared that in the absence of adequate data on O-ring function at low temperatures the decision to launch the rocket was an error.... But not well known at all is the fact that the Human Factors Sub-committee attributed the error to the severe sleep deprivation of the NASA managers. This conclusion was only included in the committee's final report, which only noted that the managers in such situations are generally the ones who sacrifice the most sleep."

(p. 54) "Drowsiness, that feeling when the eyelids are trying to close and we cannot seem to keep them open, is the last step before we fall asleep, not the first. If at this moment we let sleep come, it will arrive instantly. When driving a car, or in any hazardous situation, the first wave of drowsiness should be a dramatic warning. Get out of harm's way instantly!"

(p. 55-56) "I now think the continuum of sleepiness and alertness as the stage upon which all human behavior is acted out. Since we now can claim with confidence that where we are on this stage, from the high peak of optimal alertness to the deep trough of extreme drowsiness, is the single most important determinant of how well we perform, the total absence of this subject from psychology textbooks or any other educational materials is incomprehensible. Although the scientific knowledge has been available for more than two decades, students are still not acquiring crucial knowledge about sleepiness, sleep debt, and sleep deprivation in any of our educational institutions."

"The feeling of being tired and needing sleep is a basic drive of nature, like hunger.... Generally, people need to sleep one hour for every two hours awake, which means that most need around eight hours of sleep a night. Of course, some people need more and some need less, and a few people seem to need a great deal more or less. From the work we have done, we must conclude that each person has his or her own specific daily sleep requirement. The brain tries to hit this mark, and the farther you are from getting the number of hours of sleep you need, the harder your brain tries to force you to get that sleep."

(p. 57) "In 1970, in the same month that I opened the Stanford University Sleep Disorders Clinic...."

(p. 58-60) The Multiple Sleep Latency Test (MSLT) measures the speed of falling asleep. Scores of 0 to 5 minutes indicate that physical and mental reactions are often very impaired. "A score of 5 to 10 minutes is borderline, while a score of 10 to 15 indicates a manageable sleep load. A score of 15 to 20 represents excellent alertness."

"Once we made the breakthrough advance that gave us a precise and reliable objective measure of our tendency to fall asleep, the MSLT, Mary and I were poised to make another major discovery: The brain keeps an exact accounting of how much sleep is owed.... we discovered that the effect of each successive night of partial sleep loss carried over, and the effect appeared to accumulate in a precisely additive fashion.... current evidence suggests that the accumulated lost sleep must be paid back at some time, perhaps even hour for hour."

(p. 61) "As your debt grows, your energy, mood, and cognition will be undermined."

"Several groups of sleep researchers have carried out studies on normal volunteers.... [in which] subjects were awakened every minute or so throughout entire nights, and the next day's alertness was evaluated using the MSLT. The nocturnal awakenings were brief, 5 to 10 seconds, and subjects usually returned to sleep immediately. Although there were usually several hundred interruptions, the cumulative total sleep can add up to normal amounts. Nevertheless, daytime sleepiness is markedly increased, as if there had been no sleep at all, or very little."

"Accordingly, we may conclude that the restorative value of sleep is severely curtailed if sleep periods are not allowed to continue for at least several minutes. If 10 to 15 minutes of sleep are allowed to occur before an interruption, this effect is greatly lessened. These studies have led to the concept that there are minimal units of restorative sleep."

(p. 62) Because most college students are chronically sleep deprived, and they are the subjects used for many different kinds of tests this becomes an important consideration. "Since people are so severely affected by a large sleep debt, its presence can potentially alter the results of almost all research measures, from I.Q. tests to observations of drug side effects. The baseline studies of all human research, regardless of their nature, now must include measures of daytime sleep tendency, so that the variable degree of chronic sleep loss does not contaminate every study."

(p. 63) "We don't know what happens to sleep debt in the long term. You may have paid off those sleep-deprived periods when you got sick shortly afterward and slept 18 hours at a stretch. Or the brain may lose track of sleep debt accumulated months or years earlier."

"We know that most people completely collapse after three or four days of total sleep loss."

(p. 64) "A final answer to this issue can't be obtained until precise studies over long periods of time are carried out. Right now we know only that the brain keeps an accurate count of sleep debt for up to two weeks, because that's the longest controlled laboratory experiments have lasted [due to funding limitations]."

"...[S]leep debt is known to lower productivity and increase a tendency to be angry or violent."

"Because the alertness-sleepiness continuum is a complex function of sleep debt, biological alerting, and environmental stimulation, we are generally very bad judges of our sleep tendency. How likely we are to fall asleep is the combination of two opposing forces: our sleep load minus our level of alerting."

(p. 67) "When a crash [of an automobile] is attributed to alcohol, the real culprit, or at least a coconspirator, is often sleep deprivation.... [A]lcohol may not be a potent sedative by itself, but it becomes very sedating when paired with sleep debt."

(p. 69-70) NIH conducted some tests that included sleep in the past few years over a period of 14 weeks. The subjects were required to spend 14 hours per day in a small windowless bedroom without lights, radios, or do any thing that might keep them awake artificially. After working off their sleep debt over three weeks, "...by the fourth week they had settled down to a steady-stage average of 8 hours and 15 minutes of sleep. Some people slept a little more, some a little less. The longest sleeper regularly got about 9 hours of sleep, and the shortest sleeper got about 7.5 hours of sleep."

(p. 71) "The subjects' mood and level of energy also improved tremendously over the course of the NIH study."

"...[T]his remarkable study illustrates the principle that a small amount of sleep debt is good, indeed is necessary, for sleeping efficiently.... Most likely we need the sleep debt accumulated during our waking 16 hours, plus a little extra, in order to fall asleep in 5 to 10 minutes and sleep through the night. The idea that a little sleep debt is good is a revolutionary concept."

(p. 74) The "biological clock" and "circadian rhythms" are key components in understanding jet lag, and related phenomena such as shift work.

(p. 75) "Over millions of years, our bodies have developed a remarkably precise biological clock that ticks like a metronome to regulate sleeping and waking. The clock is an internal chronometer that marks time by basic molecular mechanisms that scientists now are beginning to unravel. Since before the birth of our species, the daily rising and setting of the sun and the seasonal flux of light's transit into darkness have shaped this molecular timepiece, until the clock itself has become a tiny mirror of the celestial clock. The rotation of our planet as it spins its way around the sun is represented in miniature within our cells. And each day the sun tweaks its earthy ambassador into alignment."

"From my personal perspective, by far the most important function of this biological clock is that it is a major determinant of our daily cycle of sleep and wakefulness."

(p. 76) "We eat, think, exercise, wake up, and sleep best when we heed the rhythm of our internal clock. Individuals who are out of synchrony with their clocks, such as shift workers who never fully adjust to nighttime work and daytime sleep, underperform both physically and mentally, as study after study has confirmed."

(p. 77-78) How do sleep debt and our biological clock interact? The biological clock initiates a period of "clock-dependent alerting" which can overcome sleep debt and keep the person from sleeping, or when it is off allow them to sleep even when there is little sleep debt. This model can be "...extended to account for periods of inexplicable drowsiness and inappropriate wakefulness whenever they occur."

(p. 79) Opponent-process model:

(p. 80) "For humans and other diurnal animals, the clock-dependent alerting process is active in the daytime and inactive at night, with lowered activity in the early afternoon.... [T]he main reason we do not fall asleep as soon as we have been awake for a few hours is that the homeostatic sleep drive is strongly held at bay by the independent internal stimulation of the biological clock. The main reason that we can sleep through the night is that we have accumulated sufficient sleep debt during the day so that the unopposed homeostatic sleep process is free to operate all night long."

"It can be said that the biological clock is the primary regulator of the daily cycle of sleep and wakefulness. Its active alerting function maintains wakefulness all day long and it permits sleep by turning off and allowing the sleep process to operate unopposed throughout the night."

(p. 80-81) "Dale [Edgar] and I and other members of the Stanford group postulate that the daytime clock-dependent alerting occurs in two waves, one in the morning (starting when you wake up) and the other late in the day (starting typically in the late afternoon, around 4:00 or 5:00 P.M.). We further postulate that clock-dependent alerting is substantially stronger during the evening period than in the morning period."

"In the early afternoon, between the two peaks of heightened clock-dependent alerting, the clock slacks off in its efforts to keep us awake. The result is post-prandial drowsiness...[due to people] feeling their accumulated sleep debt, unopposed by clock-dependent alerting. Some of us completely 'bottom out' during this time. In many cultures, people cope with this early-afternoon dip by retiring immediately after lunch for an afternoon nap."

(p. 94) "...[W]e now know that all the use of electric lights in the evening, which we previously thought had no effect, can have a profound effect in lengthening our biological day and shifting our clocks. Simple activities like checking our e-mail or reading at night have the potential to fool our bodies into delaying our biological onset of sleepiness."

"In Chuck's subjects, the natural period of the biological clock averaged 24 hours and 10 minutes, rather than the nearly 25 hours that had been documented before. Other experiments by Chuck [Czeisler of the Stanford Sleep Clinic] have now confirmed this result."

(p. 95) However, "Once we use electric lights, our clocks start lagging about an hour every day."

"The biological clock can be reset by exposure to light, the presence of melatonin in the blood, and vigorous, repetitive physical activity."

"A very important aspect of resetting the biological clock is that the clock can only be reset at certain times. These times are specific portions of the circadian rhythm. Depending upon the time (referred to as the phase of the rhythm) the resetting stimulus is delivered, the clock will be reset to an earlier time or a later time, and the change will be either larger or smaller. Obviously clock resetting cannot be done carelessly. It is sufficiently complex that specific individual instructions should be followed."

(p. 96) "With just the right laboratory conditions, Chuck Czeisler has shown that over a three-day period, the biological clock can be resent to any time desired. Though it is another story, Chuck has been very involved in resetting the biological clocks of astronauts so that they are optimally alert when they need to perform at their absolute peak."

"In 1972, two separate laboratory teams headed by Robert Moore and David Zucker identified the locus of the biological clock deep in the brain in two pinhead-size cluster of nerve cells called the suprachiasmatic nuclei, or SCN. There are about 10,000 nerve cells in these tiny clusters.... [which] sit in the midline of the brain, directly above the optic nerves.... The SCN uses this position to monitor levels of light entering the eyes and to adjust the rhythmic fluctuations of body temperature, hormone release, and metabolic rate."

(p. 97) "...[The biological] clock can function independently of any light alerting." Studies of fruit flies make it likely that this clock functions by a natural oscillation of protein production and disintegration."

(p. 99) "Our loss of sleep time and natural sleep rhythms is the tragic legacy of a single and profound technological advance -- the light bulb. When Thomas Edison invented the incandescent bulb in 1879, he became a modern Prometheus, taking fire from the gods and giving it to humans. Yet Edison accomplished something Prometheus could not imagine, because he separated the light from the fire and offered it for our infinitely more convenient and flexible use."

(p. 100) Edison's invention made it possible for individuals to greatly change their sleep patterns. "Edison thought that people got twice as much sleep as they needed and that the extra sleep made them 'unhealthy and inefficient.' ....[H]owever, there is strong anecdotal evidence that Edison was a prodigious daytime napper, whose total sleep approached the normal eight hours."

"In his emphasis on productivity and efficiency, and his equation of sleep with the sin of sloth, Edison embodied the energetic and boisterous spirit of the late-nineteenth-century Industrial Revolution. However, his invention of bright electric lights threw a dangerous wrench into the human clockworks."

(p. 102) "...[S]leep patterns are very different at the beginning, the middle, and the end of life. How much we sleep, when we sleep, and the proportion of REM to non-REM sleep, all evolve and change as we move through our lives."

"Teens have their own biological rhythm, and forcing them to adapt to an adult timetable is counterproductive, causing problems both in learning and behavior. And too many adults behave like overgrown children when it comes to regulating their own sleep habits, even when their chronic daytime fatigue tells them that something's wrong. The consequences of these behaviors range from increased traffic fatalities to decreased productivity and job satisfaction."

(p. 103) "Appreciating our personal sleep need and circadian rhythm is a two-step process. First, we have to remain attentive to our body's unique circadian patterns and know how they tend to change over the lifespan. Second, we have to respect those rhythms and sleep indebtedness at our own peril. When we harmonize our lifestyle with our body's master clock, we maximize the quality of our life -- physically, mentally, and emotionally."

(p. 104) "Sleep begins well before we are born.... [O]nce a pregnancy is well along, the fetus spends most of its time asleep -- about 16 to 20 hours per day."

When does dreaming begin? Although this issue is difficult to pin down, infants soon after birth begin to display REM sleep.

(p. 106) "We were surprised to find how much REM sleep infants have. Typical newborns spend about eight hours in REM sleep --about 50 percent of their daily sleep. More recent studies suggest that near-term fetuses actually spend about 60 to 80 percent of their sleep time in REM sleep. Most adults, on the other hand, spend about 25 percent, or about two hours a night, in REM sleep. This percentage actually drops over the course of our lives, so that by old age we enjoy relatively little REM sleep -- only 15 to 20 percent of the time asleep."

"Circadian sleep cycles also begin before birth.... [S]ignals from the mother actually will stimulate the fetus to mirror its mother's circadian cycles."

"We now know the fetus signals the mother when its body is mature and ready to be born and actually starts the labor process. But the mother has some say in the process. All mammals tend to give birth during the time they normally would be asleep, possibly to make sure the birth happens 'at home,' and therefore safe from predators."

(p. 111) "No scientific experiments have been done on how best to train an infant to sleep, but I can make a few conjectures. I doubt that a regular pattern of sleeping and being awake can ever be imposed on infants immediately after birth or that anyone should even try. Their biological clocks seem to need to mature more before they can keep track of the time of day. But the same kinds of cues that work for us should work on infants' clocks at they are maturing. Light in their rooms during the morning and dim light in the evening, as well as a feeding and activity schedule that is as regular as possible, should help put the biological clock in tune with the 24-hour day once it has matured enough to kicked in." [Studies have indicated that this starts around 17 weeks of age and by 40 weeks the baby has started waking and going to sleep at about the same time each day.]

"By the end of the first year, the overall number of sleeping and waking hours has changed relatively little. The infant still sleeps 14 to 15 hours a day. Except for one to two daytime naps, the sleep periods have shifted to the night and the waking periods to the day. By about 18 months of age, most toddlers are taking only one nap."

(p. 112) "By the end of the second year, children sleep about 50 percent of the time. Somewhere between 2 and 5 years of age, the other nap fades away. Children slowly sleep less and less until their daily sleep measures about 10 hours, which holds steady until they reach puberty."

(p. 113) "...[P]reteens tend to be very well rested.... During the...day they ...[are] like puppies, bursting with energy; at night they ...[sleep] about 10 hours. With regard to sleep and wakefulness, this is truly life's pinnacle of perfection. Think about it -- completely wide awake and bursting with energy all day long, and then deeply, soundly, and continuously asleep for the entire night."

(p. 114) " For preschoolers, the effects of delaying bedtime by even half an hour can be subtle and pernicious. Even more cases of attention deficit/hyperactivity disorder (ADHD) are being diagnosed in elementary schools and junior high school, and I think there is a good possibility that some of these kids are really just sleepy."

(p. 115) "In a way, teens are different people. Under the influence of a rush of hormones, the brain is being remade. Some nerve networks grow and become dominant, others shrink and atrophy. Over the course of puberty, the cerebral cortex undergoes a last great bloom of neural rewiring. Nerve connections keep changing throughout adulthood of course, but the scale of the change during puberty is unmatched again until very old age, when neurodegeneration starts undoing the brain organization that has been built up over a lifetime. Teenagers actually begin to see the world differently -- the same old symbols and objects begin to have entirely new meanings."

"...[H]ormonal developments are integrally tied to changes in teenagers' sleep, where one of the first signs of puberty is found. The onset of puberty is heralded by a rise in the amount of growth hormone that is secreted into the bloodstream at night."

"A decrease in melatonin levels signal the body to begin puberty. If peak levels of melatonin stay high [such as for those who take melatonin to help them sleep], puberty will not begin [on time]."

(p. 117) "Before...[our] study, everyone thought that teens would need less sleep than younger children. In fact, as they hit 13, 14, and 15, these kids were still sleeping the same number of hours as when they were younger. In addition, their scores on the MSLT showed them to be very sleepy. We were astounded to find not only that their sleep time was not changing, but also that even this amount of sleep seemed insufficient."

"What we had guessed, and what Mary's [Carskadon] work at Brown proved, is that there is a change in the biological clock during the teen years. Adolescents tend to be classic night owls, staying up late and sleeping in late. This pattern is caused by a biologically driven shift in the circadian cycle that gives teens a troublesome kick in alertness at about the time the folks around them (younger and older) are getting sleepily and going to bed. Most teenagers will not start feeling sleepy for an hour or more after adults do."

(p. 119) "...[O]nce the bloom of adolescence is over, we get only a short period in our late teens and early 20s to enjoy the fruits of adulthood in all its ripeness before our bodies start the slow process of falling apart. The muscles lose strength and mass. We begin to gain fat. Our skin begins to lose resiliency and firmness. Researchers have found that fertility can start declining measurably in many women during their early 30s. Bones start to lose mass. We get injured more easily and take longer to recover. Nature is telling us that, as far as she is concerned, we've had our day in the sun, our chance to snag a mate, and she won't waste much effort on us anymore as we drift toward middle age."

"Sleep also changes as we age. As adolescence ends, the amount of sleep we get declines slightly and continues to decline slowly into old age."

(p. 121) "A recent survey showed that over 80 percent of Americans believe you cannot both be a success at work and get enough sleep."

"Our findings in over forty carefully screened, healthy men and women ranging from 65 to 88 was somewhat surprising. Over 40 percent of these normal elderly sleepers had some form of sleep apnea, and a majority of the group suffered from extraordinarily frequent 'microarousals' -- unremembered very brief awakenings lasting only three seconds or less, but recurring between 200 and 1,000 times per night. Because the arousals were so short, their total nightly sleep time was only somewhat reduces. However, the MSLT testing showed a clear relationship between the frequency of brief arousals and the daytime sleep tendency. Even so, very few of the MSLT scores were in the 'twilight zone,' mean score less than 5."

"In adolescence the sleep phase tends to shift so that we are more owllike, but as we get older we become more larklike, falling asleep earlier and getting up earlier."

(p. 123) "It's one of the cruel ironies of life that just as we are entering retirement and finally have more time to sleep, nature plays a nasty trick on us and offers us less sleep and poorer-quality sleep."

"Ultimately we tend to die in our sleep."

(p. 124) Stanford Sleep Center.

(p. 128) "Sleep fails as the result of any of a number of malfunctioning sleep processes. Sleep disorders can arise from problems in any component of the body machinery -- from the biological clock; from injury, toxicity, physical illness, mental illness; from work and schedule problems. Sleep disorders can last one night, a few weeks, or be lifelong. They can arise at any age, from birth to death, affecting male and female alike. Some sleep disorders are completely invisible until they cause a catastrophe, and others could not be more visible."

"But whatever the cause of sleep disorders, when sleep fails the borderline between waking consciousness and sleeping stops functioning as it should; stops being the well-defined, well-controlled line we expect. We are forced to fend for ourselves in the lawless borderlands between the two."

(p. 129) INSOMNIA: "There are so many different types of insomnia, attributable to so many different causes, that it is nearly impossible to make generalizations that will describe all cases of insomnia in a meaningful way. I believe that we sleep specialists, in a laudable effort to communicate, have inadvertently imposed an awkward and rigid organization on the topic. The problem is that this organization, in my opinion, tends to obscure as much as it enlightens."

(p. 130) "Insomnia is not a disease -- it is a symptom. Insomnia is simply some sort of difficulty sleeping."

(p. 131) "The prevalence of insomnia raises the question of why human sleep can be so fragile and prone to malfunction. After all, cats and dogs don't seem to have any trouble falling asleep."

(p. 132) "Part of the cost of our fast-paced 24-hour modern lifestyle is that our psychological alerting is in overdrive, keeping us 'on call' when we most need to be asleep."

"The very first dividing line in addressing any problem of insomnia is whether it really bothers you."

"Occasional trouble sleeping is surely part of the human condition and should not necessarily cause concern."

(p. 133) "Very severe difficulty sleeping even for only several nights can not only be debilitating but very dangerous." (p. 135) "...[Y]ou should definitely be concerned about trouble sleeping when the problem persists more than a night or two, when the cause of the problem is not clear or is not easily resolved, and, most important, when there is a negative impact on your daytime function, mood, or performance. Finally, it may well be that your level of concern should be the highest when difficulty sleeping is a secondary consequence of stress, travel, pain, and so on. You are in harm's way, and whatever the cause of your insomnia, it could be horribly compounded by an unintended sleep episode [i.e., sleeping while driving]."

"...[S]leep specialists like to divide insomnia into two categories: 'transient' cases lasting only one night to a week or two, and 'chronic' cases lasting weeks, months, or years."

COMMON CAUSES OF INSOMNIA (p. 136)

Hyperarousal (p. 136): Stressful circumstances: Worry, excitement, etc.

Time Zone and Schedule Changes: "An individual's clock-dependent alerting is thrown out of synchrony with new light and dark cycles.... [S]ome people may feel better in a day or two, others don't and their body's biological rhythms take a full week or more to catch up to the new time."

Sleep Environment: Noise, new surroundings, unusual activity, etc.

(p. 139) Treatment with bright light in the morning or evening depending on when the sleeping difficulty occurs is the usual prescription when it is due to biological clock problems.

OTHER CAUSES OF INSOMNIA: Restless legs syndrome, gastroesophageal reflux, or fibromyalgia.

The basic cause of Restless Legs Syndrome is unknown. However, effective medication is available, and very effective.

(p. 143) "Sometimes the flow of stomach acid back into the lower esophagus (gastroesophageal reflux) causes sleep to be disturbed. If the acid makes it all the way to our throat and larynx, the sleeper will awaken coughing and choking.... Medications that block acid secretion are now available without a prescription, and the simple step of not eating a full meal before going to bed will also help."

"Fibrositis is a disorder associated with pain in muscles and tendons, characteristically with points of tenderness in certain typical locations. There is always daytime fatigue and very commonly difficulty falling asleep and staying asleep." Little of value to the patient is know about this syndrome.

(p. 145) "...[Another serious cause of insomnia] is central sleep apnea, in which breathing simply stops during sleep and is resumed only when a patient awakens. The severity of central sleep apnea is related to the number of times the victim stops breathing during sleep. Snoring can occur but is usually not prominent [as it is in obstructive sleep apnea]. Sometimes central and obstructive sleep apnea can occur together (mixed apnea), but in central sleep apnea itself there is no obstruction. There is no truly effective treatment for this condition. Happily, central sleep apnea is rare."

Another sleep problem "...is sleep state misperception." In this condition the patient complains that they have persistent insomnia, but when tested, they show completely normal sleep."

(p. 150) "There are a variety of general techniques that can be tried to alleviate primary insomnia. These approaches include improving sleep hygiene (which is a good idea for everyone), relaxation techniques, stimulus control, cognitive techniques, and sleep state restriction. I will discuss each in turn."

IMPROVING SLEEP HYGIENE: "Sleep hygiene includes nonpsychological elements, such as avoiding caffeine before bedtime, but many of the elements are behavioral. Keeping a regular schedule is one of the most important behaviors for healthy sleep."

RELAXATION TECHNIQUES: "The most widely known technique is called progressive relaxation training.... first by tensing and relaxing the feet, then the legs, then the hands, then the arms, and so on. They also concentrate on controlling breathing and think about the pleasant sensations. When people practice this technique during the day and before bedtime, it can be very effective in removing anxiety that interferes with sleep both at the beginning and in the middle of the night."

STIMULUS CONTROL: "One important part of improving our chance to fall asleep is to abolish as much as possible stimulating activities or thoughts as bedtime approaches."

COGNITIVE TECHNIQUES: "Techniques that engage the mind with some simple, repetitive problem are longtime favorites for battling sleeplessness. The mental attention that these tasks require offers a distraction from thoughts that interfere with sleep. Counting sheep is the classic example. Some people use repeated calculations, such as starting with a number (say, 1000) and subtracting another number (say, 17) again and again."

"Another method that sometimes works to get the mind off the subject of sleep is, paradoxically, to make staying awake a goal."

(p. 152) SLEEP STATE RESTRICTION: Patient is restricted to only 4 or so hours of sleep per night and builds up slowly to more by increments of say 30 minutes until they reach a suitable amount of sleep like 7-8 hours.

(p. 152-153) ALTERNATIVE THERAPIES: Hypnosis, biofeedback, acupuncture, massage, herbs and home remedies.

(p. 154) MELATONIN: "What we do know about melatonin is that it is a hormone secreted by the pineal gland in the brain that lets the body know that it is dark outside. For humans, melatonin directs the body to prepare for sleep; for nocturnal animals like rats, its release is a sign to start waking up."

"The sleep-inducing effects of melatonin works in counterpoint to the alerting effect of light. In very low doses (up to 0.5 milligrams for the average adult), melatonin can shift the phase of the biological clock. Melatonin rises naturally right before falling asleep, and ingested melatonin can produce the same sort of surge. Melatonin is most likely to affect the phase of the biological clock when it's synchronized with changing light levels.... [T]aking melatonin at night causes a phase-advance (earlier to bed and earlier to rise), whereas melatonin in the morning induces a phase-delay (later to rise and later to bed)."

"Since melatonin can constrict blood vessels, there is some concern that it may pose a danger for people with cardiovascular disease.... Melatonin may have effects on human reproductive cycles analogous to its effects on reproduction in other mammals [i.e., initiating sexual development at puberty]."

"When patients ask me if they should be experimenting with melatonin, I first remind them that the hormone is less carefully regulated for purity and dosage than are prescription medications, and that much more research into its actions remains to be conducted. Nevertheless, melatonin does seem to help some people, so I don't discourage interested patients from trying it in small doses as a remedy for transient insomnia and jet lag. It may help night workers sleep better during the day, and totally blind people may be able to synchronize their clocks to melatonin instead of light."

(p. 156) "I know that if people take intelligent action early in the course of insomnia, they can nip it in the bud, before it grows into a frequent or persistent."

"The biggest challenge to treating insomnia is persuading doctors and even the people who have insomnia that it is a serious problem. In our uninformed society, most doctors and lay people consider insomnia a nuisance condition even less important than the common cold or flue. We now know that insomnia can be a deadly problem that we fail to treat at risk to our lives and the lives of those we love."

(p. 157) "As a lifelong sleep specialist, I believe that the two sleep issues that are most misunderstood and mythologized by doctors and the general public are, first, the problem of insomnia and, second, the use of sleeping pills to treat it."

Modern sleeping pills are safe, effective, and not addictive. Unfortunately, it is widely believed that that they are addictive and to be avoided.

(p. 159) Older sleeping pills have sometimes been addictive and were usually ineffective.

(p. 161-163) Names the currently available sleeping pills and suggests Ambien as the best available drug treatment for insomnia: "It induces sleep with the fewest side effects in the most people."

"Most over-the-counter 'sleeping aids' have no proven efficacy."

(p. 167) SNORING AND SLEEP APNEA: Symptoms: Fatigue, high blood pressure, obesity is common, but thin people can have it too. Condition is easily treatable, when properly diagnosed.

(p. 168) "Every night more than 50 million Americans stop breathing.... Just when death seems imminent, the sleeper suddenly struggles awake and the tongue and throat muscles tighten, allowing oxygen to flood into the lungs in a series of gasping, snorting breaths. Oxygen is restored to the blood, and the fatal course is reversed. Instead of being alarmed and staying awake, the victim is immediately asleep again. After a few seconds snoring begins -- and the cycle starts again, repeating hundreds and hundreds of times a night."

"That is what sleep apnea looks and sounds like to an objective observer -- but apnea victims have no memory of their all-night life-and-death struggle for breath. It never ceases to amaze me that sleep apnea victims can awaken hundreds of times in a single night and remember nothing of that torment. It's hard to measure how much real sleep such patients lose, but it is at least a third of their time in bed. And when sleep is interrupted this many times, it has little value in reducing sleep debt."

(p. 169) "In its 1992 report to the U.S. Congress, the National Commission on Sleep Disorders Research estimated that 38,000 fatal heart attacks and strokes in the United States each year are due to apnea. I would call it the silent killer, a phrase also used for high blood pressure generally, except that obstructive sleep apnea is far from silent. People with apnea usually snore so loudly that their snoring is compared to jackhammers, sounding loud even through doors, through walls, and down halls. And yet the true significance of this loud warning remains unappreciated by people and their doctors."

"Nearly 40 percent of the population has some sleep apnea, and half of those cases are clinically significant. That means that at least 20 percent of the people walking in to see their family physician have a dangerous level of apnea. The number of doctor visits attributable to apnea is probably much higher, because apnea causes a wide range of health problems that force people to see their doctors. One of the most common problems is extreme fatigue, since apnea sufferers' actual quantity and quality of sleep is very low. Yet these people are not properly diagnosed. I conclude that family practitioners catch fewer than 1 or 2 percent of their patients with apnea. Even those with the most flagrant symptoms are rarely identified."

(p. 172) "Snoring is a sign that ...breathing is impaired while you sleep. If you snore, you need to know how badly your breathing is impaired, and what the consequences are."

(p. 173) "Not everyone who snores has sleep apnea, but in general, the louder the snoring, the more likely that the sleeper has apnea."

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1. THE PROMISE OF SLEEP, William C. Dement, Delacorte Press, New York, 1999.

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