"What a great massage. It put me right to sleep."
For many, to be relaxed enough to fall asleep is a measure of a good massage. On the other hand, for many, it doesn't take much skill on the therapist's part for them to slip off to dreamland; they are so sleep-deprived that all they need is the opportunity to let go and drowsiness overtakes them. This seemingly innocuous scenario is symptomatic of an enormous, and hidden, threat to the health of millions of people in the United States alone.
Sleep is not coming easily to startlingly large numbers of people. According to the National Sleep Foundation's (NSF) 2002 "Sleep in America" Poll1, more than half (58 percent) of the adult respondents claim to have experienced at least one of the four symptoms of insomnia -- difficulty falling asleep, waking frequently during the night, waking too early and then being unable to return to sleep, and waking up tired and unrefreshed -- at least a few nights a week. Of the respondents, 35 percent said they experienced at least one of these four symptoms every night, or almost every night, during the past year.
In addition to the four symptoms of insomnia described above, the NSF study included snoring, unpleasant tingling sensations in the legs (Restless Leg Syndrome), and pauses or lapses in breathing as symptoms of sleep disorder. Nearly three-quarters (74 percent) of the respondents said they experienced at least one symptom of sleep disorder a few nights a week or more; 37 percent reported they are so sleepy during the day that it interferes with their daily activities.
In the past century, the average time spent sleeping has been reduced 20 percent and it is estimated that within the past 25 years, the amount of time spent working and commuting each year has increased by as much as a month.2 Human error attributable to lack of sleep has been recognized as the cause for such disasters as the nuclear accident at Chernobyl, the near meltdown at Three Mile Island, the Exxon Valdez oil spill, and the explosion of space shuttle Challenger.3 The National Highway Traffic Safety Administration (NHTSA) conservatively estimates that drowsy driving is responsible for at least 100,000 automobile crashes, 40,000 injuries and 1,550 fatalities every year.4 One out of every two people suffers from sleeplessness, often chronic, and it is estimated that 30-40 million people in the United States have sleep disorders that present serious risk to their health.
Sleep, one of the most natural aspects of our lives, is clearly a problem for a very large number of people.
What is Sleep?
Sleep is a necessity of life. It is as essential to our health as air, food and water. We spend approximately 24 years -- about one-third of our lives -- asleep. Given its central importance, it is amazing how little we know about this daily part of our life experience.
Sleep is a complex and dynamic process. It is comprised of two separate and distinctly different states: non-rapid eye movement sleep (NREM) and rapid eye movement sleep (REM). These two types of sleep are as different from each other as both are from wakefulness.
NREM sleep is further distinguished by four stages, characterized by the size and speed of the sleeper's brain waves. Wakefulness is characterized by rapid, low-voltage beta waves, which are replaced by slower, higher-amplitude alpha waves as we become calm or drowsy. In light sleep (Stage 1 NREM sleep), the eyes can be observed to be slowly moving back and forth under the closed eyelids. The brain waves have shifted to theta waves and a sensory curtain abruptly drops, isolating the sleeper's mind from the outside world.5 During Stage 2, brain waves become larger, with bursts of electrical activity called Sleep Spindles and K Complexes. After 5-10 minutes in Stage 2 sleep, the brain begins to produce the large, slow delta waves of Stage 3 and Stage 4 deep sleep. During this deep sleep, the heart and breathing are regular and slow, the muscles are relaxed, and it is more difficult to be awakened.
After an hour or so, the sleeper shifts into the more highly active REM sleep, characterized by rapid movements of the eyes and dreaming. Voluntary muscles become completely paralyzed and brain waves now are more similar to those of wakefulness -- theta, with bursts of alpha and beta waves. The first REM period of the night is relatively short -- perhaps 10 minutes. As the night progresses, the sleeper moves repeatedly up and down through these different stages of sleep in roughly a 90-minute cycle, with REM periods becoming longer and more numerous. Approximately 30 percent of sleep is spent in dream (REM) sleep, about 20 percent in deep sleep and 50 percent in light sleep.6
Sleep Need and Sleep Debt
All living things have a daily cycle of activity and inactivity, if not actual wakefulness and sleep. In humans, this wakefulness-sleep cycle is timed and controlled by one or more biological clocks within our bodies. One such biological clock is believed to exist inside the supraoptic region of the hypothalamus, in the suprachiasmatic nucleus (SCN). The SCN center is partly responsible for our circadian rhythms, internal biorhythms that are strongly affected by our exposure to the cycles of day and night, light and dark.7 It "synchronizes a vast array of biochemical events in our bodies. It is the maestro conducting the complex symphony of chemical, hormonal and nerve cell activities that promote our daily fluctuations in feelings and actions."8 Most importantly, it urges us to sleep at night and awaken by day. Numerous studies have shown that graveyard shift workers whose circadian rhythms are disrupted tend to underperform both physically and mentally.
A homeostatic process is active in the brain 24 hours a day to induce and maintain sleep. Our bodies need sleep and each individual has a specific daily sleep requirement. When an individual loses sleep -- getting less than is needed -- sleep homeostasis increases the tendency to fall asleep. When extra sleep is obtained, the homeostatic process decreases the tendency to fall asleep. In this way, it is assured that, on average, an individual will have the same amount of sleep each day.
While there are individual variances, most people's sleep need is around eight hours, or one hour of sleep for every two hours of wakefulness. A few people may function fine with as little as five hours of sleep and others may require as much as 10 hours in order to feel refreshed and alert. Your individual sleep need is the optimal amount that allows you to be mentally focused and to function throughout the day without feeling drowsy when quietly sitting and being attentive to something.
A second process, called clock-dependent alerting (CDA), further helps to ensure that an individual's sleep need is met. Unlike the homeostatic sleep drive, clock-dependent alerting is not operating continuously. It is active in the daytime, promoting wakefulness and sustained alertness, and it is inactive at night, permitting the sleep drive to take over. The push-pull of these opposing processes predisposes us to be active during the day and to sleep at night.
Sleep debt is the accumulated amount of lost sleep. If this quantitative sleep need is not met on average each day, then the body accumulates a larger and larger sleep debt that must somehow be repaid. In fact, sleep medicine pioneer Dr. William Dement asserts that all wakefulness is sleep deprivation, and thus sleep debt can be nil for only a short period. As soon as a sleep debt is zero, the body awakens and sleep debt begins to be accumulated again.
Chronic sleep loss and sleep disorders are so prevalent that fatigue and drowsiness is considered normal. Symptoms of sleep deprivation -- substantial sleep debt -- include difficulty getting up in the morning, being drowsy in the early afternoon, falling asleep at your desk, low motivation, feeling sluggish and run down, having difficulty concentrating or remembering, and being irritable and quick-tempered. Fatigue and drowsiness are accepted as normal.
According to Dr. Dement, if you become drowsy at any time during the day, you have a sizable sleep debt. The stronger the tendency to fall asleep, the larger the sleep debt. The amount of time it takes to fall asleep upon lying down is an effective index of sleep latency. Those who fall asleep in under five minutes have a massive sleep debt and are living in the twilight zone, with quite impaired physical and mental reactions. Those falling asleep within 5-10 minutes are borderline sleep deprived, while those that fall asleep within 10-15 minutes have a manageable sleep load.
The first step in successful sleep management is to discover what your individual sleep need is and then to lower your accumulated sleep debt. To find your daily sleep requirement, start with your typical sleep and wake times. Keeping your wake-up time constant, go to sleep one hour earlier the next night, then yet another hour earlier the following night. Be attentive to how you feel after each night's sleep. When you feel alert and energized throughout the entire day, you've found your body's average sleep need for restorative rest.
Sleep debt doesn't go away by itself any more than financial debt does. If you need eight hours of sleep a night, and for one week you are only getting six hours of sleep per night, then you have created a sleep debt of 14 hours. A large sleep debt can be accumulated by losing even just a small amount of sleep each night. It appears that sleep debt must be repaid hour for hour. Sleeping in late on the weekend will not get you caught up for a week of sleep loss. You need to make up those 14 lost hours and usually you cannot sleep more than an extra hour or two per night because clock-dependent alerting will try to wake you. Consequently, sleep debt must be paid off in installments, rather than in one lump payment. A large sleep debt may take a long time to repay.
Napping is one way of helping to pay off sleep debt. Whereas most of us are programmed to sleep at night, particularly between the hours of midnight and dawn9, there is also a smaller "energy dip" period in the afternoon between 1 p.m. and 3 p.m.10 that is an excellent time for a midday nap or siesta. The typical drowsiness at this time of day is the result of the accumulating sleep debt of the day, made more apparent by the mid-afternoon lessening of clock-dependent alerting. If you cannot take a nap in the afternoon, it is wise at least to try to not engage in demanding activities and to reserve this time for rest or more mindless tasks. This is typically a time of decreased productivity in the workday. A 15-20 minute nap can improve alertness, sharpen memory, and alleviate some of the feelings of fatigue. However, it is important to remember a nap is not a substitute for a full night's sleep.
Sleeping during a massage is an expensive nap, but it may well be what the body needs most in that moment. Still, I consider it prudent to recognize the potential danger to the client who is so sleep-starved; they may be in a state of exhaustion and depletion. Educate them about the importance of their daily sleep requirement and the very real threat of sleep debt. Dr. Dement, in his book The Promise of Sleep, states quite convincingly that unhealthy sleep, in which are included chronic sleep deprivation as well as various sleep disorders such as insomnia, Restless Leg Syndrome, sleep apnea, etc., is the largest, deadliest and most costly health problem facing the country.
If you have difficulty sleeping and feeling rested, are sleeping poorly for a month or more, or if you find daytime drowsiness interferes with your normal functioning, consult a physician knowledgeable about sleep medicine. Unfortunately, conventional medical training gives little attention to sleep. Nearly two-thirds of U.S. adults have never had physicians inquire about their sleep. Contact the National Sleep Foundation for a list of accredited sleep disorder centers in your area.
Sleep well. It may save your life.
Originally published in Massage & Bodywork magazine, August/September 2002. Copyright 2003. Associated Bodywork and Massage Professionals. All rights reserved.