Sleep is one of the first essentials in maintaining or in building vitality. There are differences of opinion as to how much sleep may be necessary to health, but that sufficient sleep is required if one wishes to maintain the maximum of energy no one can question.
Sleep is far more necessary than food. One can fast for many days, or many weeks if necessary, and without any special disadvantage if he is well nourished before beginning the fast and has a satisfactory food supply after its conclusion, but no one can “fast” from sleep for more than a few days at a time without experiencing ill effects. One can scarcely endure an entire week of absolute sleeplessness.
It has been found that dogs kept awake even though sufficiently fed, suffer more than when deprived of food and permitted to sleep. When kept awake continuously they die in four or five days.
Man can endure the strain a little longer than the dogs, but five or six days usually marks the limit of human life under such conditions. In early English history condemned criminals were put to death by being deprived of sleep, and the same method has been employed in China. Enforced sleeplessness, in fact, has been used as a form of torture by the Chinese, being more feared than any other. The men subjected to this frightful ordeal always die raving maniacs.
These facts illustrate only too well the imperative necessity for sleep. Unfortunately “late hours” prevail, especially in large cities. Manifestly, if complete lack of sleep is fatal, late hours and partial lack of sleep is at least devitalizing and detrimental to health. The late hours kept by large numbers of people in civilized countries undoubtedly contribute very largely to neurasthenia and allied diseases.
Improvements in artificial lights have contributed largely toward the increase of the evil of late hours, injurious not only through the loss of sleep entailed, but also because of the eye-strain incidental to strong artificial lights and the drain on the nervous system. If civilized man would follow the example of primitive man and of many of the birds and animals in retiring to bed with the coming of darkness and arising with the appearance of daylight, this one change would revolutionize the health of the whole human race.
How much sleep do we need?
This is a question that cannot be answered arbitrarily as applying in all cases. Individuals differ. Without doubt, some require more sleep than others.
Thomas A. Edison, who is an extraordinary man, not only in respect to his vitality but in every other characteristic as well, has frequently been quoted as saying that most men and women sleep too much. Mr. Edison himself claims to maintain the best of health with from three to five hours’ sleep out of every twenty-four. We have heard of other cases too, of men and women with exceptional vitality, who have seemed to thrive on four or five hours’ sleep. It is possible that this small allowance of sleep may be sufficient in such cases, but if so, it is undoubtedly due to the exceptionally powerful organism which these particular persons have inherited.
No definite rule can be laid down as to the amount of sleep required by different individuals, for those possessing the greatest amount of vitality and the strongest organisms will require less sleep than those of limited vitality and weak functional powers. Those possessing a strong functional system and great vitality are able to build up energy during sleep and recuperate from the exertions of the preceding day more rapidly than can those less favoured in this respect.
In other words, a very strong man can be quickly rested. His system can more rapidly than that of a weak man repair the wear and tear of his daily work. The man or woman with limited strength and a less vigorous functional system would require a longer time in which to recuperate. Therefore, what would hold good in the case of such an extraordinary man as Mr. Edison cannot be depended upon in the case of the average man or woman, and certainly will not meet the needs of those who are debilitated and striving to build vitality.
Generally speaking, therefore, I maintain that most people at the present day sleep too little rather than too much. I would not stipulate any special number of hours for sleeping but I would advise everyone to secure as much sleep as he requires. It has often been said that if you sleep too much you will be stupid as a result. Such results are usually brought about by sleeping in unsatisfactory environment, particularly in stuffy rooms in which the air is vitiated and really unfit to breathe.
I cannot imagine one feeling stupid as a result of oversleeping when sleeping out-of-doors, or when the supply of air is absolutely fresh. Excessive heat would probably be conducive to restlessness, but this is purely a detail which I shall take up later. Under natural and healthful conditions one will rarely sleep too much. If you sleep until you wake up naturally there is little danger of your sleeping too much. Without doubt most people need from seven to eight hours’ sleep; some of them need more, particularly women and children, who in many cases require from nine to ten hours’ sleep or even more. These are general statements. Individual exceptions will be many, but, as I have said, it will be found that those who need less sleep are men and women of extraordinary vitality.
The quality of sleep is really more important than the duration of sleep. It is quality or depth of sleep that is really what counts, and to secure this it is necessary that certain healthful conditions be observed. The first of these is a normal condition of physical or muscular fatigue. This is easily distinguished from nervous fatigue or exhaustion in which the entire system is more or less upset. Abnormal states of this sort arise from excitement, excessive mental work, or other conditions involving severe nerve strain. This nervous fatigue is not usually conducive to sleep, but a tired condition of the muscles of the body generally, as a result of natural physical activity, is always favourable to sleep. Many who complain of insomnia, therefore, would often be able to remedy their trouble by the simple expedient of a long walk, covering sufficient distance to bring about the physical fatigue which makes sleep possible. Conditions of air, temperature and bed covering are also important factors in connection with the quality of sleep.
If you are a sound sleeper it may be possible for you to secure more benefit from three to four hours’ sleep than a shallow sleeper may secure in eight hours of a lighter degree of sleep. This extreme depth of sleep means complete rest for the brain, absolute loss of consciousness, and, to a certain extent, loss of sensibility in respect to our senses. In the lighter degree of sleep certain parts of the brain may be at rest, while others are more or less active.
Dreaming represents a state of partial consciousness rather than a condition of complete rest, inasmuch as various parts of the brain are active. One may thus be conscious of his dreams. There is no doubt, however, that in other cases various parts of the brain may be active though we may not be conscious of their activity. We have all heard of instances where mathematical problems appear to have been worked out during sleep, and we have heard of musical compositions and poems being produced during sleep. All these phenomena represent a condition in which one is partly asleep and partly awake; in other words, some parts of the brain are active and others are asleep.
In extreme depth of sleep when all the mental faculties are at rest, the energies are relaxed, and the activities of the body are at a low ebb; it is such sound sleep that makes for rapid recuperation. The deepest sleep generally occurs within the first few hours after falling to sleep, and it gradually becomes lighter and lighter in degree until consciousness is reached. Dreams, therefore, represent partial consciousness and usually appear in the earlier hours of the morning. When one states that he dreams all night he is invariably mistaken. One may seem to live over periods of days and even years in a dream, the actual duration of which may be measured in minutes. The chances are that the dreamer enjoyed a sound sleep before his dreaming commenced.
Although I have said that depth of sleep is more important than the duration of sleep, yet it is true that when one sleeps very soundly he usually sleeps longer. In other words, when one reaches great depth of sleep the transition to the period of wakefulness is only gradual, and it requires a longer time to complete the sleep and wake up than it would if one did not sleep so deeply, or, as we would say, so soundly. It will be found that healthy children, who unquestionably sleep very soundly, also sleep for many hours at a time. They may have dreams but these occur in the later hours of sleep, as every mother has observed. The man or woman well advanced in years who can secure the same depth of sleep that a vigorous child en joys will undoubtedly spend the bigger part of the night in sleep and will acquire exceptional vitality as a result.
Bodily rest, even without sleep, is undoubtedly of great value for purposes of recuperation. To a certain extent such rest, especially if associated with a state of very complete relaxation of the muscles, will make it possible to take less sleep without serious devitalizing results. The man or woman who suffers from insomnia should learn that he can recuperate to a considerable extent through simple physical relaxation without the unconsciousness of sleep. Undoubtedly the physical inactivity common among civilized races has much to do with their ability to keep late hours. But of course this involves more or less nerve strain. The brain does not get sufficient rest, and the loss of sleep involves such an expenditure of energy through the brain as to constitute a serious drain upon the nervous system. Even though rest for the body during consciousness is of certain value, it cannot go very far in taking the place of true sleep. To the higher centers of the brain and nervous system an opportunity must be given for the complete relaxation that comes only with the entire loss of consciousness.
As I have already said, those who are lacking in vitality and who are trying to build strength need more sleep than those who are already strong. Especially those who find it difficult to sleep need additional nervous strength and should carefully observes rules that will promote sleep. One will often hear sufferers from insomnia complain that they never sleep! They are convinced that night after night and week after week passes without their being able to close their eyes in slumber. They are deluded in every case, because they could not maintain life for more than five or six days if this were true.
The fact is that they drop off to sleep and then awaken without being conscious that they have been asleep. At the same time, in all such conditions, it is necessary to improve the quality of sleep so that it will be truly refreshing. I have already referred to the influence of good healthy muscular fatigue as a means of enabling one to sleep. Walking and out-of-door life will in almost every case make the nervous man or woman sleep like a child. One should not be too fatigued, but sufficiently so to thoroughly enjoy the sensation of lying down. One cannot truly enjoy sleep except when he has reached this condition of bodily fatigue. To induce this, I would recommend a walk in the evening before going to bed, covering several miles. Although walking for health should ordinarily be brisk enough to stimulate breathing and arouse an active circulation, thus strengthening the internal organs, for the purpose of promoting drowsiness the last mile or two of the evening walk should preferably be very slow. Fast movements are stimulating to mind and nerves. Slow movements have a sedative effect. By walking very slowly as if one were tired the desired effect of fatigue is more satisfactorily secured. One imagines the need of rest under such conditions.
The quality of the air is another important factor, though I need not dwell upon that here. The air you breathe during sleep should be especially fresh and pure, particularly so because of the more shallow character of the breathing. If you are in a room, all the windows should be open as wide as possible. If you have a covered balcony or porch, or if you can avail yourself of a flat roof, it is always advisable to sleep out-of-doors. The increased vitality will more than repay you for your trouble. There is something about out-of-door sleeping that vitalizes, energizes, and refreshes one to an unusual extent.
Circulation is another important factor in sound sleep, especially for nervous persons. Many of those who complain of an inability to sleep suffer more or less from congestion of blood in the brain; also they complain of cold feet or cold hands and feet. In such instances, warm feet will often bring a solution of the problem. In some instances drinking a half cup of hot milk or hot water before going to bed will draw the blood from the brain and enable one to sleep. A hot foot bath before going to bed will do the same thing, or one may use a hot-water bag or hot flatiron wrapped up in flannels, or even a hot brick treated in the same way, to keep the feet warm when in bed. In extreme cases it might be advisable to apply cold packs to the head while applying heat to the feet or when taking the hot foot bath.
Another measure of special value for nervous persons is a bath at the temperature of the body, to be taken for a half-hour before going to sleep. In cases of extreme excitement, anger or nervousness this bath is invaluable. Fill the tub with water at 96 degrees Fahrenheit or 98 degrees Fahrenheit. You can remain in this bath for several hours without harm, for it is neither weakening nor stimulating. It has a soothing effect upon the nerves and is even valuable in preventing attacks of hysteria or other nervous difficulties. This particular bath is so effective in hospitals for the insane that it has frequently obviated the use of padded cells and straight jackets. It is just as effective for the nervous person who wishes to overcome the excitement that is preventing sleep. A half-hour bath should be sufficient for ordinary purposes. Another remedy of great value for soothing the nerves is the air bath. I have referred to this in another part of this volume, but it is extremely valuable for quieting the nerves in cases of insomnia. If the room is comfortably warm, an air bath can be advantageously taken for half an hour before going to bed.
One of the most valuable remedies for those suffering from sleeplessness is to lie in an air bath during the entire night. This idea can be carried out very easily by raising the bed covering in such a way as to remove its weight from the body, thus providing what we might call a chamber of air in which to sleep. With the aid of a large safety-pin or a horse-blanket safety-pin, the bed clothing may be kept thus suspended. The safety-pin is pinned through all the coverings in the centre of the bed and then by means of a string passing through the safety-pin and running from the top of the head of the bed to the top of the foot of the bed the bed covering can easily be raised to the desired height. The appearance of the bed is then somewhat like that of a small tent. One may not feel warm immediately after entering, if the weather is cold, but if the covering is thick enough and the air is entirely excluded, a perfect air bath, warm and comfortable, can be enjoyed during the entire night. The head, of course, will keep its usual position outside of the covers. No underclothing or night clothing should be worn when attempting to carry out this idea.
The problems associated with covering are of considerable importance. Many people are unable to sleep because of cold feet and many are overheated by an excess of covering. It should not be necessary to bury one’s self underneath a heavy load of covers in order to keep the feet warm. Use as little covering as possible and still maintain the bodily warmth. Eider-down bed covers are very valuable because of their light weight and great warmth-retaining qualities. Overheating during sleep produces restlessness and robs one of the sense of refreshment on awakening. The question of cold feet I have already dealt with. The difficulty, in most cases, is one of defective circulation before going to bed. If one will be sure that his feet are warm and his circulation good before retiring to bed he will invariably have no trouble of this kind, even during winter time. I do not mean that one should be chilled by insufficient bedding, but I certainly would advise as little covering as is compatible with a comfortable degree of warmth.
The feather beds, much used in Europe, are undesirable, as they are unsanitary and are too warm for nearly all seasons of the year. It is always best to sleep between clean linen sheets. For purposes of warmth, however, bear in mind that cotton is of very little value, whereas animal-product covers such as wool and down, or feathers, are exceptionally warm. Cotton comforters in cold weather are very heavy, but cold, whereas woolen blankets, wool-filled comforters or down-filled comforters are warm, but light. “A warmth without weight” should be the chief consideration in cold weather. And in using woolen coverings you can get sufficient warmth without much weight and with the very least quantity of covering. In summer use only a single woolen blanket or a light cotton coverlet over the sheet. When the nights are hot and sultry it would be well to use no covering of any kind.
For warmth in winter special attention should be given to warm fabrics underneath the lower sheet as well as the coverings. One may become chilled from underneath if lying upon a thin mattress or an uncovered mattress. A wool-filled comforter, or double woolen blanket, placed over the mattress and under the sheet will contribute greatly to one’s warmth. If the mattress is of proper thickness one can be comfortable with less covering and therefore less weight. However, I would suggest as a better plan the one that I have presented of sleeping in a virtual air bath the whole night through.
The use of a pillow is necessary in nearly all cases. When one is sleeping on his back a pillow is certainly an objectionable feature. It tips the head forward and is conducive to round shoulders. A pillow is of value when sleeping on the side or in the partial face-downward position, as indicated in the illustration.
The accompanying illustration shows a special position that I can recommend for securing restful sleep and for insuring deeper respiration. In this position you sleep with the body tipped forward partly upon the chest, and on the forearm, with one elbow just back of the body and hand under the waist. The knee of the upper leg will be drawn up somewhat. While this is a very comfortable position its chief advantage lies in the effect upon the respiration. It will be noted that in this position the organs lying below the diaphragm are placed in a suspended position, so to speak. The stomach and other organs by their own weight pull downward from the diaphragm, thus naturally allowing more space in the lungs, and particularly in the lower part of the lungs. Through the simple effect of gravitation, therefore, this position allows one to breathe a larger amount of air through the entire night. One may turn from one side to the other in order to change the position, as it will be equally comfortable on right or left sides. In cases where there is weakness of the heart the left-side position can not be recommended if discomfort of any sort is noticed.
One often hears a reference to beauty sleep and is often asked: “Is it really true that an hour of sleep before midnight is equal to two hours after midnight?” There are many writers who claim that the time when you sleep matters but little if you secure a sufficient amount of sleep. It is doubtful, however, if this view is absolutely correct. I am inclined to lean towards the old-fashioned view as to the good effect of early retiring on beauty development that is based on health building.
In one sense, it is reasonable to conclude that an hour of sleep before midnight is worth more than an hour thereafter. I am satisfied that there is greater exhaustion of the body from late than from normal hours, and it is difficult to get the full benefit from sleep when going to bed after midnight. At least the nerve strain of artificial light tends to produce a certain degree of vital depletion that one would not experience if his waking hours included only the daylight. Then again, there is probably some mysterious influence that we do not fully comprehend which makes sleep at night more restful than sleep during the daylight. Those who go to bed at midnight or thereafter use several hours of daylight in the early morning for sleeping. I realize that there are nocturnal animals and that the human race has developed nocturnal habits to a certain extent, but the human race and the animal life of the world generally have followed the habit through the ages of sleeping at night. Without doubt a revolutionary change in this habit has more or less effect upon the restful character of our sleep. Perhaps the mere question of light has much to do with it. Daylight is stimulating. Light has a chemical action and tends to stimulate animal metabolism. Darkness, or the lack of light, tends to a restful condition. Without doubt this question of light has much to do with the supposed benefits of sleep before midnight. The old saying that “early to bed and early to rise makes a man healthy, wealthy and wise” may not hold true in the matter of wisdom and wealth in all cases, but there is no doubt it has much to do with the development of health and vitality.