Sleep is much more than simply not being awake. It is an active process. It is a nightly voyage we take into the expansive, convoluted, dimly understood regions of our unconscious mind. The reasons for this nocturnal passage of the 24-hour cycle remain mostly a mystery to science. As is the repeated theme of our intricate physiological design, there is still much more to be learned about sleep. We do know that something important is happening during this darkening of our awareness because the entire body system changes during sleep—heart rate, temperature, kidney function, brain waves—all are altered. At least two very large studies of over one million participants each indicate a relationship between sleep and health. In one study the longest life spans were associated with about seven hours of sleep. That does not prove a causal relationship, but it does indicate that people who get that amount of sleep tend to live longer. The well-known Breslow study done in Alameda County, California, also identified seven health habits which contribute independently to better health and longer life. Seven to eight hours of sleep per night was one of the seven contributing factors. *136
There are over 10 billion brain cells which create extremely active brain waves pulsating with electrical alacrity from all parts of the brain during our waking hours. These active, somewhat random waves are called beta waves. As we fall asleep we enter into a light sleep characterized by slower, more regular alpha waves which seem to wash over the entire brain surface. Brain waves slow down even more in the delta phase of slow-wave sleep. As the night progresses we move in turn through four different phases of light to deep sleep. The body alternates between these sleep stages in predictable intervals, though the amount of time spent in the various sleep stages may differ somewhat from one individual to another.
Generally, most sleeping time is spent moving between deep and REM sleep. Slow-wave sleep contributes to about eighty percent of this nightly venture, and REM makes up the other twenty percent. *137 REM is named for its characteristic rapid eye movements. It is sometimes referred to as paradoxical sleep because brain waves during this time are very similar to those when we are awake. *138 If one could see the movements of the eye under the lid, the eyes would be rapidly looking side to side as well as up and down. This is dream sleep, and is vital in order to awaken fully refreshed. It is speculated that one's rapid eye movements may be following the action of his or her dreams.
It is curious that while the eyes are in perpetual motion, the rest of the body goes into a state of seeming paralysis from the neck down. In animal experiments it has been demonstrated that when the nerves which activate this muscle paralysis are severed, the animal seems to act out its dreams in body movements. A video presentation depicting this phenomenon in a cat graphically portrayed the cat acting out a range of activities from exaggerated leaps to running and crouching as though it were chasing butterflies or stalking prey.*139 Who knows what our own activity would be if we were not confined to our beds by this temporary paralysis?
It is thought that dreams may be a way of sorting and organizing our experiences. REM sleep is also the stage of sleep in which heart rate, respiration, and blood pressure are altered. During this time the body uses more oxygen, the pituitary gland is stimulated, cerebral blood flow increases, and there is a rise in the temperature of the brain. *140 A specific amount of REM sleep seems to be required for our health and well-being. Researchers have discovered that hallucinations result when individuals are experimentally deprived of REM sleep for a night or two. This same research indicated that when the subjects were allowed to sleep without being awakened on subsequent nights they spent proportionately more time in REM sleep as if to make up for the lost time.*141 Another study showed that when people are deprived of sleep for long periods, they seem to have special psychotic episodes which coincide in cycle time to their missing REM sleep intervals. Barbiturates and alcohol can suppress REM sleep. *142 Sleep deprivation in general can have dire consequences. A colleague once related an interesting research incident regarding sleep in which young men at an eastern university were paid to go as long as possible without sleeping. The winner went ninety-six hours, four twenty-four-hour days. He got his money, but his brain slowed down for more than four months. He had to repeat his entire senior year in college.
One of the most crucial tasks taking place during sleep is that of restoration and repair. The body needs rest to successfully accomplish this task. When you exercise, muscle tissue is broken down, and it is during sleep that these tissues are built up and restored. Hormones and other forms of energy stores are depleted during the day and take time to be replenished. The RNA in cells becomes depleted periodically and requires rest to be restored. *143 RNA and DNA are both compounds which enable genetic information to be stored in living cells and passed on to future generations. DNA is found within the cell nucleus and RNA is contained within the cell fluids outside of the nucleus. Since sleep is a time of physical rest, larger quantities of oxygen are available to assist in these restoration processes because it is not being diverted to energize physical activities.
Many people greatly underestimate the value of sleep as a contributor to the optimal functioning of our immune system. This fact should be evident from our own experience with needing to sleep more to recover from an illness, even when countering the common cold. The nervous system especially needs a full complement of sleep to be at its best. The endocrine glands, so important in stress control and vigor of the body, have schedules—regular times to expend energy and regular times to build up and rest. That is why one senses an energy slump and may feel irritable or depressed without proper rest. The body is letting you know that you have put it into a deficit condition. A study reported in the November 1994 Tufts University Diet and Nutrition Letter found that weight control experts may have overlooked a potentially significant factor: too little sleep. A small body of intriguing research shows that when subjects had either less than three hours of sleep or interrupted sleep for three nights in a row, all reported a greater appetite, varying from slight to marked increases. In another study of young men deprived of REM sleep for several nights, five developed a marked increase in appetite and three gained a few pounds. Explanations for this data range from the obvious fact that more calories are being utilized when one is awake than asleep to theories derived from animal research which indicate that lack of sleep disrupts the body's temperature setpoint or process of heat regulation or both, thereby increasing caloric need.
It cannot be concluded that lack of sleep will make one fat, but it can be said that people who are tired eat more, and more often. Another study reported in the December 1992 University of California at Berkeley Wellness Letter stated that loss of sleep results in decreased mental performance. Even the loss of one night's sleep is likely to result in fatigue, irritability, inability to concentrate, and mood shifts. Creative thinking and the ability to deal with unfamiliar situations are also diminished by lack of sleep. The disruption of both circadian rhythm and one's sleep cycle are most likely overlapping contributing factors to the consequences of sleep loss.
It is easy to cut corners on sleep. Some have suggested that the national debt would pale in comparison to our sleep deficit. Sleep needs vary according to age and the individual. It has been theorized that sleep is necessary to allow the brain to accomplish the long-term structural and chemical adjustments necessary for learning and memory. That may be one reason why infants require so much sleep and why seniors require less.*144 We know for a certainty that lack of sleep diminishes creativity, mental acuity, efficiency and vitality. There are many more physiological consequences of sleep loss which we are still seeking to understand.
Most of us cut short our full complement of sleep in order to gain the time to do something else which we perceive to be more important. That probably says more about our priorities than anything else. If we are already living an overextended, stressfilled life, then certainly the logical solution is not to diminish the very time our body needs to be restored. Everything goes back to the importance we attach to taking care of ourselves. We cannot put our health on hold without holding back the life-promoting results of cooperating with nature's wisdom.
Was this article helpful?