# Popular Science Monthly/Volume 67/September 1905/Sleep and its Regulation

Layout 4
* SLEEP AND ITS REGULATION.
By Dr. J. MADISON TAYLOR,
PHILADELPHIA, PA.
SLEEP as a factor in physical economics ranks in importance with respiration and digestion. Those who live normally, who throughout all ordinary exigencies maintain a natural attitude toward life, its strains and reponsibilities, may expect to enjoy a full measure of this restorative function. How much each one needs is not to be determined by dogmatic rules or precedents, nor does each one require the same amount under every condition or circumstance. There must be enough, daily and weekly, and of suitable character, to restore the balance of neural energy reduced by whatsoever of fatigue follows upon daily activities; otherwise the sensorium resents this deprivation in one way or another. Individual needs vary and can only be determined inferentially, giving due weight to generally accepted requirements.
Sleep, being the completest form of rest, is needed most by the youngest and least by the oldest. Most sleep is required by the weakest and least by the strongest. During childhood and exhaustive states too much sleep is rarely possible. For those in full tide of vigor too much sleep is often distinctly hurtful. Many modifications will immediately suggest themselves to those who are wise or learned in the science of bodily growth, development and disorders. Experience always counts for much. Variants, sometimes wide, are often permissible. Large errors will arise when these qualifications are marred by caprice, taste, prejudice; and harm follows, of one sort or another, sometimes of serious degree, by obscuration of sane reasoning on what may seem to be obvious and simple facts.
Physical efficiency depends chiefly upon the kind and amount of effort expended. Rest is an inevitable corollary. Relaxation is the starting point of all effort. For example, the strongest blows, the most accurate thrusts, can only proceed from an arm in thorough equipoise. Equipoise presupposes a full quantum of energy. Animal energy depends upon adequate rest as much as on force-giving foods. Complex acts, conditional always upon harmonies between intact central nervous dynamos, and well-adjusted mechanisms, can only be performed in their completeness when forces are at the norm.
Sleep is an absolute necessity for conscious beings. There are those who oppose this view, and some require relatively little, and that, ​too, for long periods. Some sleep lightly, retaining in greater part their consciousness. Occasionally we hear of an individual who has lived for a long time without sleep, so far as can be determined, and yet has continued to maintain good health. Sufferers from one form or another of nervous exhaustion are often compelled to forego sleep temporarily. Vigorous persons of pronounced personality and highly developed consciousness have the least need for sleep, at least while at the zenith of their powers and in the full flower of energizing.
The maintenance of conscious life demands an expenditure of energy so intense that the processes of nutrition and reconstruction of cellular waste can not be carried on without sleep. Complete repose of the consciousness is demanded for the plastic nutrition of the organism and the accomplishment of vegetative life. Consciousness is the highest of our faculties, rendering possible moral and scientific ideation; it demands the greatest efforts of our organism. In its absence sleep is less required.
All the internal organs are, during sleep, relatively less filled with blood because then the skin is in a state of hyperemia or gorged with blood. The sweat glands act more energetically at night whether we are asleep or awake, hence the danger of chills is then greater. All the organic activities continue, but are less vigorous at night, and during sleep, whereas during sleep in daylight hours these proceed with little alteration. When animals or men feel the desire to sleep they instinctively seek a quiet sheltered spot, as free as possible from light and noise, thus avoiding whatever impressions from the external world are liable to be subjectively translated into sensations. The eyelids are lowered; a position is sought wherein the muscles can be fully relaxed. The sensorial organs are capable of acting during sleep and continue to transmit impressions into conscious sensations.
With the pallor of the brain, which occurs in sleeping animals, the cortex ceases to react so readily to mechanical, photic, electric or other stimuli. The spinal cord and sensory nerves do not sleep, yet sensations of pain are then lowered. The nerves transmit painful impressions, but the consciousness of the sleeper perceives them incompletely. The voluntary muscles become quiescent during sleep, but retain their power, as shown by the normal subject in changing position, arranging the bedclothes, even walking; soldiers are able to march or ride while asleep. The brain is the chief part which sleeps, but it is not wholly inactive, exciting inhibitions which check the formation of reflex movements. If stimuli are applied of sufficient intensity to overcome the protective states of the somnolent consciousness the subject awakes, recognizing the cause more or less certainly.
Sleep is not an absolute arrest of cerebral activity; the brain then retains always partial energy. In deprivation of sleep it is the brain ​which suffers most, while in deprivation of food it is the brain which preserves longest the integrity of its structure and function. In young animals, abundantly fed and cared for but kept awake, there follows serious lesions of the organism which soon become irreparable, and death results.
There have been many theories and hypotheses advanced to explain the phenomena of somnolence. The physiologists have here, as so frequently elsewhere, exhibited far more academic than practical interest in the matter. There is no subject, however, of greater importance, since it is a prime factor in all the reparative phenomena of life, standing at the foundation of nutrition; yet no research work has been done on the nature of sleep commensurate with the gravity of the subject. Psychologists have written extensively on one phenomenon of sleep, viz., dreams. Normal sleep has attracted so little attention that we do not know exactly how to modify it in accordance with common conditions of bodily derangements. Inferentially certain facts seem established which not only account for the phenomena of sleep, but enable us to reason from them and thus to regulate the state in great measure; sometimes sufficiently. It is probable that during sleep there is a diminished resistance in the surface vessels, inducing lowered blood pressure, hence smaller amounts of blood pass through the brain. As sleep approaches the cerebral vessels grow relatively less filled with blood for an hour or more after full somnolence has come. After reaching its minimum tension the brain circulation remains practically constant for one or two hours or more, gradually returning to normal as the time for awakening nears.
After having attained a fair idea of what sleep is, whereby we can better appreciate a reasoning from our individual standpoint, we may proceed to discuss its regulation. For the young, who may be assumed to be in possession of full neural and circulatory balance, whether in or out of health, the regulation of sleep is a simple matter, one which will in most instances adjust itself if the subject be placed under normal conditions.
We may fix our attention most profitably upon the status of sleep in those of middle or late life. Here a number of causes conspire to disturb equilibrium of body cells, sometimes slightly, and at others it will be found that effects have been insidiously wrought which may suddenly obtrude upon our attention, causing great distress, often impairing the integrity of our judgment, hence our working efficiency. Therefore a double peril assails. Mere inability to sleep naturally, or as heretofore, or as each one assumes as a right, is, especially among men (who shrink from admission of physical weakness), seldom regarded as worth their seeking the advice of a physician. Whereupon the simplest remedy is to hunt about for something which will obtund ​the consciousness. Often this is a form of alcohol. A friend will advise a glass of whiskey at bedtime, may be two or more; beer is popular for this purpose; some special form of wine is often recommended, and (deplorable as it may seem) too often by the physician.
The entering wedge is so easy, and in the main agreeable in its primary effects, that the habit of tippling is thus readily established. Or again the chemists' shops are filled with 'simple harmless remedies for insomnia.' The sign boards in all public places glisten with advice. Every acquaintance is ready with counsel, especially those numerous well intentioned women with little else to do but to prattle of their shallow convictions on matters coming within the narrow range of their experience, medical, spiritual or social. It is never safe to play with drugs; to trifle with agencies often hurtful to a profound degree in their ultimate effects. Idiosyncracies exist, too, whereby what may harm one not at all produces in another far-reaching derangements of vital organs. One of the most dangerous lunatics I ever saw was a man possessed by sudden homicidal tendencies. He would have remained so had not it been discovered, by providential accident, that he was accustomed to use habitually moderately large doses of some bromide. The obsession promptly and permanently disappeared by total withdrawal and the use of an antidote. We physicians, especially those who see many instances of nervous derangements, are constantly coming in contact with the deplorable derangements caused by hypnotic drugs, many of which are ordinarily classed as innocent. The action of narcotics presents none of the characteristics of normal sleep except the temporary arrest of consciousness; hence narcosis is not true sleep. It does not refresh and regenerate vigor as does normal sleep. To be sure, drug unconsciousness may and often does pass into sleep. Again there are those who have become so accustomed to narcotics that, when deprived of them, they can not sleep. This would seem to prove a sort of antagonism between the drug effect and natural sleep. In brief, whatever agents inhibit cerebral activity, inducing local anemia, hence permitting sleep or narcosis, are harmless provided they do not derange nutrition or cause other ill effects. All narcotic drugs invite these evil effects in varying degrees and hence are to be avoided, and only used in extreme cases and under guidance of a competent physician.
The other peril lies in the fact that derangements of sleep often foreshadow serious structural damage of the heart, arteries or other organs or tissues. Hence unless the phenomena be estimated intelligently, in the light of other than obvious data only to be secured through careful medical examination, a deadly disease process may escape detection until too late to accomplish full repair.
To secure regular consecutive sleep it is best to assume that ​position which is most natural and best suited to invite the least disturbance of the functions of the great organs. To use the analogy of the four-footed animals, and by such facts we can secure the safest guidance, the best position is on the abdomen or nearly so. Habits may, and do, vitiate our instincts here as elsewhere, and we can accustom ourselves to many departures from natural and advisable operations. This is especially forceful while in vigorous health, but we are speaking here of securing the best rest with the least tax upon our organism, hence it is well to determine those means which are normal, and employ them. The body should lie as nearly as possible on a level, head and feet as well as body, on the side inclined toward the abdomen, adjusting arms and legs in such a fashion as shall not permit undue pressure upon nerves and bloodvessels, direct or indirect.
To lie on the back is objectionable for the reason that long continued pressure on the tissues adjacent to the vertebral column, which are innervated by the posterior primary divisions of the spinal nerves, exerts a continued irritation through vasomotor connections to the viscera, disturbing the circulation in the segments. Here are the cell bodies of the vasomotor nerves, which thence pass to the organs and beyond parts, thereby governing function. Thus, dilatation is induced and maintained in the blood vessels of the viscera. Also certain results follow directly by effect of gravity. Pressure on the abdominal organs, and their varying contents, is exerted upon the great vessels, arterial, venous and lymphatic, the sympathetic plexuses, and the ebb and flow of fluid in them is deranged. Hence function and nutrition of these structures are influenced unfavorably. Man is the only animal which sleeps on the back. This attitude should only be assumed for short periods. During extreme weakness this position is often taken, but it is the duty of attendants to urge a frequent change to the side, otherwise several hurtful effects may follow, among which the least grave are nightmare and evil dreams. The poisons of katabolism circulating in the blood tend to be deposited in the outlying tissues; hence arise pneumonia and bedsores. Not only is this true for those who are suffering from one or another form of disability, but for those in robust health, especially when sleeping on the back after full meals. Many obscure forms of digestive or circulatory disorders may have been initiated in infancy through lying too long upon the back.
In animals, among whom such disorders are rare and whose spinal column is constantly horizontal, there is little or no change in the relative positions of the great organs at any time. In man, who is constantly altering the relationships of these viscera by lying, standing, stooping, the blood supply and venous return are subject to frequent interruptions, and strains are exerted upon the supporting structures ​of the blood vessels and thus the vasomotor mechanisms are taxed heavily. The head should be permitted to rest as nearly upon a level as the feet, though most people prefer some support. The blood should be encouraged to reach all parts of the body equally, hence the limbs had best be extended, not flexed; the habit of extending the arms above the head is a particularly bad one.
To secure the most perfect repose the temperature of all parts should be equalized before retiring. Cold feet induce delay in securing sleep and it is then shallow when attained. The bladder and bowels by weight of their contents will interfere with repose, hence they should be previously emptied. It is most unwise to overfill the stomach before retiring; this disturbs sleep almost as much as hunger, but moderate eating before sleeping is not hurtful, and is often salutary.
Sleep is only a function; therefore, whatever disturbs it depends on structural derangement of some sort. Disorders of sleep are manifold. The commonest are psychic exaltations or depressions, worries, brooding on the cares of the day, continuing to dwell on the waking problems. Habit is ever forceful. A well-trained mind will promptly shut off or readily let go of the thought processes. Unnatural activity of the sensory and association centers causes dreams; that of the motor centers results in shocks, starts and spasmodic phenomena. Control of the visceral centers may become inhibited, permitting unconscious discharges from the bladder, intestines or sexual organs; innervation of the lungs or heart being thus deranged, palpitation or dyspnoea is induced. Sensory centers being over-stimulated, sensations of light follow, or of sound, also pain or vertigo. "In fine, the ordinary smooth current of the subconscious activities breaks against some pathologic states and now one symptom, now another, is thrust out and so unpleasantly that the sleeper awakens" (C. L. Dana).
A review of Dana's remarks on the disorders of sleep will be useful to achieve an understanding of the varieties and phenomena of insomnia; a better term perhaps would be difficulties of sleep. Some people, especially those of middle age, fall asleep easily, but wake in the small hours and thereafter only doze fitfully. This may be due to beginning degenerative changes in the arteries, connected with the effects of worries and strains, or only a habit, or echo of youthful customs of early rising, or an acquired weakness or irritability of the heart. Others fall asleep readily, but are soon disturbed by little explosions of motor, sensory or psychic forces. The body or limbs start or jerk; sleep follows, but these nervous explosions may be repeated two or three times. It is usually the result of exhaustion, psychic or muscular over-tension, physiologic irritability, indigestion, nervous fatigue, or may foreshadow some serious derangement. Sudden awakenings often betray emotional distress, fear or disorders of ideation.
​Weir Mitchell has written fascinatingly of disorders of sleep, making absorbing reading for the profession as well as the laity. He it was who described first the sensory shocks, strange feelings passing along the body, culminating in some abrupt explosion, noise, odor or vision. Vertigo is occasionally thus experienced, especially by those who have felt it before. That mysterious malady called 'migraine' sometimes occurs suddenly while asleep 'and hales the sufferer from profound sleep to waking hours of misery.'
Morbid or perverted sensations, numbness, 'pins and needles' formications and such like mild neuroses appear at times during sleep. Limbs may seem 'dead,' sensation being temporarily lost and not in any way which follows upon marked pressure interrupting the flow of nervous impulses, but purely a phenomenon of sleep. These are more common in the later hours of night, when the motor cells are restored in part, losing irritability, the sensory cells being still excitable. These discomforts may be referred to interruptions in the conductivity of the spinal cord. Nocturnal psychoses, the night terrors of children, nightmare, strange mental vagaries, changes in intellectual and emotional balance, are of such wide variety that they can only be alluded to; each person of rich experience is able to recall instances. In these conditions of distress much folly can be committed, and frequently is; evil thoughts are thus engendered, which too often influence action later. Sometimes imperative impulses arising in slumber drive one to commit questionable or silly deeds. The imagination in some is thus stimulated to utter weird statements, or to put on record what are falsely estimated to be thoughts of deep significance. I recall reading an incident in the early official life of Bismarck, who often thus wakened in the night with the conviction that he had solved perplexing problems. On reducing to writing the ideas thus excited he found, on perusal next day, that they were altogether fanciful. It is true, valuable ideas do come in dreams or in real temporary waking states.
The sleep of early life is peculiarly sensitive to irritations of the organs below the diaphragm, digestive or genital; in later life to those above, of the heart, blood vessels or lungs. In this connection we may refer to dreams. The suspension of brain activity in sleep is only partial; there prevails a certain amount of psychic life. Every nervous stimulus, sensation or idea leaves an impression, a trace, in the cerebro-spinal system. Obscure motions, influences, irritants generated in the organism, may afterward revive temporarily under some impulsation of consciousness, as by afflux of blood. Each cell of the body is endowed with more or less memory (Henle), for by this means are preserved hereditary influences, the transmission of psychic and mental characteristics, the after images of sensations. In this manner many sounds, sights, feelings, which are partially conveyed to the sensorium, ​may become revived and variously interpreted to the consciousness. Predormitial sensations, thoughts and movements are thus capable of inducing multiplication and diverse auto-interpretation. Dreams grow luxuriantly when the state is one of partial wakefulness. The influences of the day are then woven into fanciful pictures more or less reflecting actual life.
If sleep be profound the imagination is no longer dominated by actualities and there arises the phenomenon of a special world, that of dreams. Mental activity is really physical activity; hence we may experience consequential fatigue. At the bottom of the emotion may be found a subjective excitation of the peripheral nervous apparatus. This form of reflected life constitutes the basis of dreaming, the imagination, hallucinations, the realm of fancy. Dreams have their origin in those parts of the organism most active in the waking state, in eyes, ears, the tactile, temperature and muscular sense. The same obtains as to hallucinations in the insane. A very deep sleep does not permit of dreams, or the waking memory can not recall them, whereas in very light sleep dreams are frequent and can be remembered.
Dreams are more numerous and picturesque among intellectual people, and during certain exhaustive states, and less among those of lower mentality. The more primitive, young and intellectual the person, the more illogical, disjointed and elementary are the dreams. In old age, and profound depressive states, dreams are most rare; they serve many useful purposes. To the physician certain features of dreams possess a valuable significance. They exercise a salutary influence upon otherwise unused areas of the brain and permit the excursions, or, may be, formation, of the faculty of imagination (Manaciene). They act as a defense against the monotonies and trivialties of real life, for without them we should grow old much more rapidly (Novalis). Many writers, poets, scientists, philosophers, musicians, etc., testify to the value of dreams in piecing out their concepts, idealizations, weaving a woof of imagination invaluable to the completed thought.
It will be seen that the regulation of impaired sleep reaches back to causes most varied. Some are slight and superficial; others are due to deep-seated derangements or lesions, beginning or established. In practise, however, certain plain simple procedures usually suffice to bring about happy results. Beyond what these can accomplish, skilled medical aid should be sought and a careful search made for definite disorders, and systematic measures instituted to remove them consonant with the difficulties encountered. It is well to remember that the causes of wakefulness may be highly complex; slight factors often acting with equal forcefulness with those which theoretically should be greatest.
We are concerned in our efforts to regulate the resting period of ​the consciousness, with possible morbidity in two directions; too much or too little. Ordinarily it is assumed that the more one gets of sleep the better. This view is so generally accepted that the custom of some physicians, especially those who see much of illness in the extreme periods of life, to order food or employ active measures at regular hours, involving the waking of the patient, verges upon the danger line. Judgment must be exercised, and is well within the capabilities of a good nurse. Serious exhaustion has often followed needless interruptions of repose during exhaustive states.
It is entirely demonstrable that a variety of disorders may result from, or are indicated by, excessive somnolence, partly of developmental and partly of degenerative origin. During infancy sleeping must predominate over waking states, the unconscious reflex life over the conscious intellectual life. It should be remembered, however, that consciousness requires exercise for development. Monotonous measures, such as rocking, swinging, unmusical lullabies, may serve a salutary purpose occasionally, but can readily be carried too far, to the point of lowering normal temperature, inducing excessive anemia of the brain and disturbances of circulation. Sleep should come by opportunity, comfortable position and customary environment. Habits should be formed sufficient in themselves to invite repose. It ought not to be interrupted needlessly, nor forced by measures or drugs which obtund the consciousness. Normality of sleeping capacity is the product of intellectual equipoise. Stupid folk are proverbially dull, lethargic, with large capacities for deep sleep. Some part of this is no doubt the result of over indulgence. The consciousness is often enfeebled by disuse in young or old. In the young the impetus to exercise the faculties demands encouragement; also, as age enfeebles the brain structures, mental stagnation, hence degeneration, is invited by overmuch time spent in unconsciousness. Nutritive balance, the expenditure of energy, can not be maintained indefinitely. Renewals must occur, and it is shown that inordinate somnolence makes for exhaustion of body and mind; the kidneys suffer, their vessels become distended and hence enfeebled. In the aged the tone of the tissues, especially of the vessel walls, tends to become devitalized, leading to a stasis in lymph and blood vessels and to various forms of organic derangement. In deep sleep, long continued, this stasis of blood and lymph is unduly encouraged, sometimes to the point of paralysis. The bile becomes thickened, stagnated; the bowels, the intestines, suffer from a surfeit of sleep, impairing the machinery of peristalsis, hence follows constipation. The urinary organs also share in this derangement of elimination and gravel, calculi, may form. Anemias are often unaccountable, but it will be found that chlorotics usually sleep too much and are the better for its regulation.
​There is no simple fact more forcefully borne in upon the writer than that early rising and movement in the open air before breakfast is a measure of vast importance in a large array of chronic ailments, especially those involving gout, dyspepsia, constipation, obesity and disorders of the sense organs. Many people aver that they are made miserable by rising early, stirring about before taking food, and consequently suffer from headaches, nausea, prostration and the like. These phenomena are the results of some derangements in the circulatory balance, most probably due to a morbid quality of sleep, which for the most part is remediable. In proof of this statement is the fact, usually clearly demonstrable, that if the physician can secure fair cooperation, with persistence all this wretchedness will disappear. Particularly is this shown if circumstances compel the patient to alter his habits for the better. Abundant illustrative instances could be cited. Weir Mitchell in his recommendations for the rest treatment, so valuable in the repair of profound conditions of exhaustion, compels a fixed hour for wakening, usually seven a.m. Often it has been the writer's duty to soothe and explain to Dr. Mitchell's patients, who resented being awakened, the reason for this regulation.
Disuse of muscle is followed by atrophy; so of other tissues. Strength can only grow by judicious, continued use. Witness the pitiable spectacle of steady degeneration in the tissues, in mental and physical aptitudes, commonly displayed in those of advancing years, who, through withdrawal of normal stimuli to exertion, permit their organs and their structures to fall into disuse. Prosperity, interpreted so often to mean cessation of energies, is often fatal to physical and mental efficiency. The antidote is simple and most effective, the retention of habits of usefulness applied all along the whole line of normal activities.
The whole range of bodily derangements and diseases can be interpreted through variations in the blood supply. This again depends upon the incidence of diverse irritants, infections from without or poisons generated within; or such as are the products of changes in the blood plasma effecting oxygenation.
Sleep being the relaxation, suspension, of the consciousness, the brain being the center of consciousness, it naturally follows that, as evidence shows, the circulation in the brain is, during sleep, at the lowest normal tension. Whatever disturbs sleep, therefore, probably induces an afflux of blood to the brain. It is evident that to sleep peacefully and continually it is important that the blood pressure shall be as nearly as possible normal. If this be markedly above or below par sleep is interfered with. Plethoric folk, however, supposedly of over-tense vessels, often sleep better than the feeble and weakly; yet they are more likely to slumber heavily, are difficult to wake, and on ​waking suffer from morning confusion and headache; in short, are far less refreshed by their slumber and require longer to acquire waking balance than frail beings whose sleep is shallow, interrupted and seemingly insufficient.
All these facts and reasonings from vascular tone constitute a long, somewhat technical, story; suffice it to say that, in order to secure comfortable natural sleep there is demanded a careful regulation of blood supply and distribution. Where a careful regulation of life fails to accomplish this, help must be sought of a wise physician, who will promptly determine what is amiss. The difficulty may be found to be due to faulty skin action, cold extremities, intestinal accumulations, or visceral poisons, organic derangements, a weak heart, an overtired body, an overwrought brain or other physical disorders, the province of the physician. Interference with matters out of the realm of our experience is usually followed by punishment. Among the most dangerous things a person can do is to take a shot in the dark in medical procedures, swallowing medicines on blind guesses. Damage must almost inevitably result, first by deranging digestion, perhaps already at fault, and next achieving stupor, not true sleep, or encouraging the brain to demand meretricious, unsuitable soporifics.
While it is most desirable that sleep should be taken in regular amounts, at a suitable time, and this during the hours of darkness and continuously, still it is possible that various habits may be formed, seemingly peculiar, which suffice for ordinary requirements. These may be acquired to meet some temporary demand, or become habitual for years. For instance, mothers of young babies commonly form the habit of sleeping and waking readily and frequently, and yet continue to enjoy excellent health. Trained nurses acquire even more complex, yet systematic, habits of sleep and wakefulness; a regular irregularity, yet productive of little or no exhaustion, at least for a time. Persons engaged in diverse strenuous occupations secure a power of seizing sleep when they can get it, notably sailor men by 'watches' of four hours each, twice a day.
Sleep, being the chief restorative agency for the consciousness, the desideratum is chiefly to achieve enough repose in sufficient completeness to effect repair of brain cells and other centers of energy. In those whose lives are full of repeated and emphatic demands upon them for concentration of attention, the habit of taking short naps is found to be most refreshing and invigorating. Many physicians, some lawyers, and other professional men who pursue literary work, find it satisfactory to secure a brief sleep some time during the day, often in the middle of operations, when an opportunity offers. Thus a short sleep in a chair, or preferably lying down on the back on a bench or lounge, will rejuvenate the powers and permit intellectual work far ​into the night. While a certain number of hours of consecutive sleep are imperative for full health, these can not be dogmatically determined except by carefully weighing circumstances, which vary. Lumber men on the 'drive' maintain excellent health on the smallest amount of sleep, during the most trying circumstances, after intense physical exertion so long as the spring daylight lasts, often wet to the skin, with little or no bedclothes or protection at night from freezing weather and fed irregularly, often insufficiently. Armies, exploring parties and others have similar experiences, and suffer no distress for days and weeks, the men often actually gaining in health, seldom losing. If the circumstances be cheerful, such competition, overcoming the forces of nature, is salutary. If peril, strained attention or tyrannous officers complicate the conditions, ill health may appear early and is then often severe.
When to sleep is again a matter of opinion. Early rising is by common consent a salutary custom, especially when the day comes early, not otherwise. It is agreed that more sleep is required in winter than in summer. The best sleep is had during the hours of darkness. The mind is clearest in the early morning, and those who can utilize this period for intellectual work are capable of turning out the best products. Some can not do so, or think they can not, and yet furnish excellent results.
The sleeping room should be cool, abundant air being always admitted. This should not be interpreted to mean that the room may safely remain intensely cold. In the modern treatment of tuberculosis fresh air is recognized to be imperatively needed all day and all night. Artificial heat can, and should, be supplied along with the fresh air, till the temperature of the room be at or near 50° F. or 55° F., for some even 60° F. Above this no one in health is likely to sleep in perfect comfort. Babies and invalids need a heat of from 60° F. to 70° F., even more at times, yet all require the fresh air, or fullest ventilation.
Fever patients, even those suffering from pneumonia or bronchitis, may sleep with safety and great advantage in a thoroughly ventilated cool room and with no more covering on them than is needed for protection from sudden changes of temperature which might send their body heat down below normal. It is needless to particularize as to the offensiveness, deleteriousness, of the body and lung exhalations emitted by those asleep. This is more than apparent, it is actually greater by far than when awake, and demands prompt removal and an abundance of good air to replace that which is vitiated. There are those who still cling to the shred of demon influence which causes them to 'dread the night air' when spirits range and goblins weave evil spells; when diseases come wafting in at open windows, keyholes ​and other joints in the harness of defense. Since the pestiferous mosquito has been proved the chief carrier of mephitic paludal diseases, insect nettings are deemed sufficient to ward off evil nocturnal influences. Sleeping in a close exhausted atmosphere is so promptly and painfully punished by discomforts, that it would seem there could not be two minds on the matter. Yet many refined and educated folk still prefer the shut windows. Curiously enough some woodsmen, farmers and others who live much in the open air incline to a hot room for sleeping. To my sorrow, I have often been compelled to experience this prejudice.
Body clothing at night should be loose, not dense, permitting the ready passage of air, never of wool next to the skin. Bed clothing should not be too close of texture, blankets being preferable to dense 'comfortables' and not 'tucked in' too closely. Air should be allowed to pass occasionally under the sides at least as one turns about more or less freely. I have proved this in open camps in bitter temperatures, thus using less clothing than those who slept in bags. Indian guides often sleep with their heads covered and their feet bare to the fire. Even on the long trail I prefer pajamas to close fitting day underwear at night. Under these circumstances, too, occasionally rising and warming by a fire gives better rest than to stay close in a sleeping bag all night long. As to beds the firm mattress with springs is vastly better than soft clinging surfaces.
Some people sleep with a profundity, a completeness, from which they can only be aroused with difficulty. They occasionally wake unrefreshed with confusion, headaches, stiffness and soreness of limbs. This is unfortunate and usually betokens some abnormality in health which should be corrected. Such deep somnolence is not so restorative as the lighter forms of slumber. Again limbs become cramped, hence nerves and blood vessels suffer hurtful pressure, by long remaining in one position; the integrity of the internal organs likewise is imperilled. Sleep is invited by darkness. Light, even though the eyes be closed, penetrates the lids and stirs the consciousness through these most delicate of sense organs. Hence it is wise to exclude light if one must sleep after the sun has risen. A useful device is to cover the eyes with black cloth or even a handkerchief folded, or use a screen, rather than to exclude daylight from the entire room, which too often means exclusion of air as well. Those whose heart and arteries lack tone may give attention to this to secure or to maintain sleep. Day drowsiness and night wakefulness indicate often a cardiac weakness demanding attention. Conversely, high pulse is usually present in those who sleep over heavily.
A complete circulatory balance is needed for those who would sleep most refreshingly. One of the best means to secure this is by exercise ​at bedtime, enough to distribute the blood to the surface and muscles, hence to relieve the tension in the vessels of the brain. High vascular tension is often a cause of insomnia; it may be continuous or only due to psychic causes, worries, morbid tension, over-excited circulation or toxins. Hence the common device of the hot foot bath, hot entire bath, or even a cold bath inducing reaction, may suffice. To execute some systematic movements with little or no clothing on is better; in cold weather with extra clothing on, such as a sweater. Certain movements, especially those of the neck and shoulders, are particularly useful. A series of movements I devised in treating a chronic neurosis put many patients promptly to sleep. Also certain manipulations of the neck, especially a distributed pressure over the posterior occipital nerves, have in certain cases of obstinate insomnia in my hands been followed by complete cure. One man who claimed he had not slept a full night for thirty years was thus put to sleep in my office and after a course of treatment he remained free from this distress. That admirable instrument, now unfortunately out of fashion, the bicycle, cured scores of insomniacs by affording patients the means of prompt lowering of blood pressure by a ride just before bedtime. Few measures are more prompt, certain and permanent.
Eating some light food is often of value, but the overfull stomach is frequently a cause of shallow or distressed sleep. There are many forms of digestive derangement, liver troubles, toxemias, etc., which impair sleep in those who are under the impression they have powerful digestions. Nothing wakes some people so certainly at evil hours as an over-acid stomach, relievable by a simple alkali or charcoal. The bowels are best evacuated before bedtime; if full they may cause much loss of sleep. In short, as Emerson says of all health, of which sleep is a major item, it is not to be bought, it must be earned; and wisdom, frugality, self restraint, industry, perhaps all cardinal virtues, contribute to this boon.