SUBJECTIVE AND OBJECTIVE QUALITY OF SLEEP: AMOUNT OF SLEEP AND NEED FOR SLEEP.
Everyone troubled with difficulty in sleeping is accustomed to keeping exact records of the number of hours slept. While it is easy to keep track of time with the aid of a clock, it is far more difficult to measure mental states or feelings of contentment. The reason for keeping such records is because of a subjective expectation concerning sleep, especially the amount of time slept. The quality of sleep is less tangible and is more difficult to measure and assess.
Another psychological factor is at work, however, in this need for an exact record-the unstated comparison with the healthy sleeper and with an established sleep norm. People with sleep problems often have the erroneous idea that normal sleep results from a physiological need to sleep a specific number of hours and is the condition for conveying the subjective feeling of "having slept enough'' or of' 'having had a good night's rest."
The notion of a specific quantity of sleep is related to the idea of its restorative effect. Thoughts are automatically paired, and much sleep is equated with feeling fresh, feeling rested is equated with a capacity for work. Conversely, a little amount of sleep is equated with
tiredness, dullness, and inefficiency.
It has already been mentioned how difficult it is for the poor sleeper to judge the length of time slept. But it is the poor sleeper who makes astonishingly exact notations of the times he "didn't sleep at all," including detailed calculations of the hours and minutes. It would be very tempting once to put such assertions of "not having slept at all" to a test in a sleep laboratory to demonstrate that many of the periods that seem to the poor sleeper to be waking periods are in reality dream phases or stages of light sleep. It could be shown, too, that several short sleep periods do amount to real sleep, even though perhaps only to a small amount of sleep.
Many problem sleepers simply have difficulty in accepting their individual condition of being short sleepers. They cannot resist making constant comparisons with the seemingly normal sleepers in their vicinity and confronting themselves with what they believe to be their own sleep deficit. The eight-hour norm regrettably accepted by so many people as standard is as untenable as prescribing a generally valid amount of food to be consumed by everyone or as establishing a norm for sexual behavior.
In addition, it seems altogether possible that the characteristics of a person's sleep are partially an inherited tendency.
Research with families have revealed certain types of sleepers, short sleepers and long sleepers. If the short sleeper has the possibility of investigating the question, he may find that even as a child he was always considered a mischief-maker who was forever awake, could hardly be brought to take the usual morning or afternoon nap, was awake in the evening, and full of life in the morning. If an infant who was only accustomed to sleeping ten hours were able to suspect himself of being a short sleeper, he would be horrified to compare his own sleep record with that of other infants in the vicinity who sleep 15 to 18 hours a day.
The most well-known short sleepers of all time, Edison and Napoleon, are repeatedly quoted as having gotten along on two hours of sleep. Edison is reputed to have discovered the light bulb in order that man should not have to waste so much valuable time in his life by sleeping. Napoleon's sleep habits prove that periods of great activity by no means required being offset by periods of much sleep. On the contrary, during periods of great activity and efficiency, it is sometimes possible to get along with very little sleep. Certainly the need for sleep is evidently very different among different individuals, and many an alledged sleep disturbance is the result of not knowing one's own sleep requirements. Therefore fatigue and exhaustion are to a large extent the result of a psychic reaction to what is perceived as a lack of sleep and would be much less frequent complaints if many people simply accepted the fact that they are four- or five-hour sleepers.
An additional factor is that when there is a lack of sleep, the sleep periods missed vary in importance to the organism, depending upon when they occurred, since other bodily functions adjust to the wavy, rhythmic course of sleep. If the autonomic nervous system just happens to be in a phase of excitation, it can make a waking phase very disagreeable through such manifestations as heart palpitation, anxiety, and perspiration. Because of the readiness for deep sleep in the hours after midnight, a waking period around this time will result in a minimal feeling of being refreshed and restored and a maximal feeling of fatique and exhaustion. If the person remains awake, sleepiness diminishes with the approach of morning and the feeling of being refreshed and capable of activity increases even though the organism was unable in the interval to be restored by additional sleep. For this reason, a period of being awake shortly after midnight is subjectively more serious and depressing than a period of being awake toward morning. By the time morning approaches, one's whole mood is better,
enabling one to make a more positive evaluation of one's own state and the approaching new day. Even the low point at a big dance is biologically predictable to be around 2:00 a.m. Conversely, most people feel physiologically revived toward morning.
The amount of sleep registered by one person as normal can therefore be registered by another person with the feeling of a torturous sleeplessness.
But the feeling of restoration, apart from the psychic evaluation just described, is also dependent upon the quality of sleep, i.e., it is dependent upon the various sleep phases, their length, and the order in which they occur. Moreover, the often satisfying feeling of "I have slept" seems to be particularly related to the periodic alternation between synchronic and asynchronic sleep periods. If this alternation is absent, there is no feeling of recuperation. We will discuss this fact again in connection with the use of sleeping pills.
A comparison of laboratory sleep records of long sleepers and short sleepers, both of which groups consider themselves normal sleepers, shows that the decisive factor in the restorative effect of sleep is not the amount of sleep but the maintenance of certain sleep phases. Evidently some sleep phases can be dispensed with. Consequently both types of sleepers can have approximately the same number of deep sleep phases, including REM phases, but can vary in the intervals of light sleep or the respective length of the separate sleep phases. The transitional phases of light sleep can in fact be completely missing among short sleepers without producing the feeling of having had an insufficient amount of sleep. The short sleeper simply sleeps more concentratedly, to some extent "faster."
The general maintenance of a certain relation between the totality of the dream phases and the other sleep periods seems to be important for achieving the greatest perceptible restorative effect. But it cannot be proved which form of sleep is more desirable, short deep sleep or
long even sleep. It is therefore impossible to assign any exact normal values for the length of time slept. The range of variation is from five to ten hours. But even this statement represents values that can vary in either direction.
What happens, though, if sleep is totally withheld? Numerous experiments of immense value to problem sleepers have been made in the course of years by volunteer test subjects. This should be constantly kept in mind if you become nervous and desperate in the course of a sleepness night when thinking about greeting the next day with a lack of sleep. Man can tolerate being without sleep for longer periods than is generally imagined. From experiments in complete sleeplessness, the records show periods longer than 200 hours. The longest record is alledgedly held by a 17-year old student from San Diego who managed to spend 264 hours without sleeping. Admittedly he did not work during that period of time, which amounts to 11 days and nights!
As already mentioned, though, complete lack of sleep occurs only in an experimental situation when the subject is effectively impeded even from the slightest attempt at sleep. Under normal conditions, the organism obtains the minimal quantity of sleep needed, even if in very small, subjectively hardly noticeable intervals. The body is able, however, to make up in one night for even a long sleepless period. In other words, the regenerative capacity is extraordinarily great, at least in this area.