"Sleep is the indispensable condition to the recuperation of energy. We go to bed fatigued andget up refreshed.
Sleep repairs the wear and tear of the body and mind incurred during wakinghours.
Nothing is so restorative to the nerves as sound and uninterrupted sleep. Sleep is thus avital element in a total way of life. It is a basic need in man’s mental as well as physical life. During sleep most of the functions of the body are carried on at the lowest level possible inhealth. Heat production is from 10 to 15 per cent below the basal level. The mechanism regulating the body temperature are less sensitive than in the waking state and are depressed by 0.5 to 1.0 degree F. The rate of the heart is reduced by 10 to 30 beats per minute and adecline in blood pressure of about 20 mm occurs in quiet restful sleep. The urine volume isconsiderably reduced, but its concentration in solids is increased. The tone of all the skeletalmuscles is lessened. The eyes are usually rolled upward and the pupils constricted.
Loss of sleep exerts seriously detrimental effects upon the nervous system. Long periods ofwakefulness may cause profound psychological changes such as loss of memory, irritability,hallucination and even schizophrenic manifestations. During the last World War, prisoners inNazi concentration camps who kept awake for days by strong lights and blaring wireless sets,collapsed.
Sleep versus rest
For correct living, it is essential to differential between sleep and rest. At rest the body isdisturbed by all exterior noises ; but in sleep it is screened from them by partial loss ofconsciousness and also by what is called " dream protection. " One useful purpose of the dreamis to convert outside noises that might awake the sleeping person, into fantasies that do notdisturb him. During rest the limbs are normal, but in sleep they swell. Blood flows from the brain, distends thearteries, and makes the limbs bigger. IN sleep more muscles are relaxed than in rest, though the sleeping person changes his position about 35 times in one night, without knowing it. Many organs which work during rest suspend their activities in sleep. Thus the recouping value ofsleep is much more than that of rest or simple lying down.
Theories of sleep
Many theories of sleep have been advanced to explain the temporary loss of consciousnesswhich we know as sleep. The oldest theory is that sleep is induced by a reduction in the bloodsupply to the brain or at least to conscious centres. This is known as ischemic theory. Even theancient Greek physicians were aware that the carotid artery was in a way concerned with the onset of sleep. The name itself expresses this belief. The Greek word ‘ Karotides’ for carotidarteries is derived from karoo which means ‘put to sleep.’ In modern times, the drowsiness aftera meal, presumably due to the diversion of blood from the brain to the digestive organs, is citedin support of the ischemic theory. Another important theory about sleep is the chemical theory. As a result of experiments in themetabolism of sleeping subjects, it is considered that the fatigue inducing sleep may be a mildform of blood poisoning or toxaemia.
This "poisoning" is believed to be brought on by the expenditure of energy during the waking hours.According to this theory, every contraction of a muscle and every impulse passing through thebrain or the nerves breaks down a certain amount of tissue. The debris from broken down tissueis then thrown into the bloodstream. In the waking state, much of the waste from broken downtissue is got rid of through the natural eliminating processes of lungs, kidneys, bowels and skin.
But there comes a saturation point when there is such an accumulation of waste that it cannotbe disposed of by these processes and it then invades the grey matter of the brain. In such aneventuality, mental and physical altertness are impaired. It is nature’s warning that the wasteproduct must be reduced to replenish the lost energy. So we get tired and the urge to get sleep becomes irresistible.
Duration
Another mystery about sleep is that no two persons need the same amount of sleep. Dr.Nathaniel Kleitman, Associate Professor of Physiology at the University of Chicago, whoconducted years of extensive experiments at the University’s "Sleeping Laboratory" says thatthere is no more a normal duration of sleep than there is normal height and weight. A study of 25 subjects spread over thousands of nights showed that the average amount of sleep needed tofeel well rested is seven-and-a-half hours, though individuals varied from six to nine hours.According to Dr. Demmis Williams, a noted authority on sleep, the amount of sleep needed foran individual’s well-being, is determined by what he feels he needs, not by what other people,including the doctor, think is reasonable.On the whole, women sleep from 45 minutes to one hour more than men. The amount of sleeprequired varies at different ages as follows :
New Born : 18 to 20 hours
Growing children :10 to 12 hours
Adults : 6 to 9 hours
Aged persons : 5 to 7 hours
The depth of ordinary restful sleep fluctuates throughout the sleep. In most adults, sleepdeepens through the first hour, after which it lightens rather sharply and then more graduallyuntil morning or until the usual time of wakening. IN growing children, however , sleep deepens asecond time for a little while. According to Dr. Lindlahr, a famous naturopath, two hours beforeand two hours after midnight are the most valuable for sleep of all the twenty-four hours of theday. In these four hours, mental and physical vigour are at their lowest ebb and sleep issoundest and most natural.It is believed that three-quarters of our sleep consists of whatis called ‘ slow wave sleep.’ Therestorative processes occur during this time.
The remaining quarter is taken by what is called‘rapid eye movement (REM) sleep.’ It is also called paradosical or dreaming sleep and it comesin episodes of about 20 minutes duration about five times in a night. It involves dreaming,irregular heart rates, raised blood pressure and erection of the penis. It is in this phase of sleepthat normal healthy young men may have wet dreams. Both forms of sleep are consideredequally important, being normal sleeping rhythms.
Sleeping positions
There are many theories about good and bad sleeping positions. Practically everyone changespositions several times during sleep. Hence how one starts out is of no consequence. It is agood thing we do turn about in our beds. If we did not, we would awake in the morning stiff,having maintained the same position all night. For proper sleep, however, one should not sleepon one’s back but on the side with one or both legs brought well up and the head and theshoulder slightly forward.
Sleeping pills are no remedy for sleeplessness. They are habit-forming and become lesseffective when taken continuously. They lower the I.Q. dull the brain and can prove fatal if takenin excess or before or after alcohol. The side-effect of sleeping pills include indigestion, skinrashes, lowered resistance to infection, circulatory and respiratory problems, poor appetite, high blood pressure,kidney and liver problems and mental confusion.Sleeping well is an art. It needs a perfect blend of healthy habits and control of mind. A cleanbody and mind, relaxed mood, physical exercises, and perfect dietary control are some of thebasic sleep-inducing methods.
Unpleasant situatins at bed time such as arguments, quarrels, watching a horror movie, listeningto loud music which would create anxiety, fear, excitement and worries should be avoided. Such situations stimulate the cerebral cortex and tend to keep one awake.The sleeping place should be well ventilated, with balanced temperature and free from noises.The bed should be neither too hard nor too soft, but comfortable. The pillow should not be toohard or too high. The bed clothes should be loose-fitting and light coloured. Another importantrule is not to have heavy food shortly before bed time.