SLEEPING

&
HEALTH
By Leggett & Platt
Ergonomic Research Center

Are you getting the sleep you need?

Sometimes just prying your eyes open can take a mighty effort.  Your body feels achy and drained.  You’re edgy, irritable, foggy.  The problem:  not getting the rest you needed.  One any given night, one of every three men, women and children is tossing and turning.  Come morning, millions of sleepless souls are starting the day on empty.  Sleep problems have become a modern plague that is taking a tremendous toll on our bodies and minds.  Desperately trying to fit more into the hours of the day, many people are stealing extra hours from the night.  One of every five North Americans may be living in a twilight zone of sleep deprivation that undermines their health, sabotages their productivity, blackens their mood, clouds their judgment and increases their risk of accidents.  Yet even those who want to sleep more often can’t.  In recent surveys, half of men and women say they’ve had trouble sleeping.  And problems making it though the night invariably mean difficulties making it through the day.

What is a good night’s sleep?

The answer doesn’t depend solely on how many hours you lie in bed.  Night after night, you need deep, uninterrupted sleep in a bed that provides adequate comfort, support and space.  If you wake up full of renewed energy, you’ve had a good night’s sleep.

Normal sleep times range from five to ten hours; the average is 7 ½.  About one or two people in one hundred can get by with just five hours; another small minority needs twice that amount.  But keep in mind that sleep needs change with age.  From infancy to adulthood, sleep decreases by more than half.

What happens during sleep?

As we sleep, muscles tense and relax.  Pulse, temperature and blood pressure rise and fall.  But, you don’t simply “fall” asleep.  You descend slowly through different levels.  As you close your eyes and drift off, you enter the first stage of what is called quiet sleep.  Your brain produces irregular, rapid waves, and muscle tension decreases.  You breathe smoothly, and mundane thoughts float through your mind.  If roused, you might jerk awake quickly and deny that you’d slept at all.

In Stage 2 of quiet sleep, your brain waves become larger, punctuated by occasional sudden bursts of electrical activity.  You’ve definitely crossed the border between wakefulness and sleep.  If someone lifted your eyelids gently, you wouldn’t waken; your eyes no longer respond to stimuli.

As you descend into Stage 3, your brain waves become slower and bigger.  In this state of slumber, your bodily functions slow down even more.  Finally, stepping into Stage 4, you reach the deepest sleep, the most profound state of unconsciousness.  On and EEG (electroencephalogram), your brain waves would appear extremely large and slow.  You are so “dead to the world” that even a thunderstorm might not wake you.  This step-by-step journey into oblivion usually takes more than an hour.  Then you begin to climb upward, moving rapidly through the same sleep stages as before, not all the way to full wakefulness but into active sleep.  Because the pupils dart back and forth, this stage is called Rapid Eye Movement or REM sleep.  (The four stages of quiet sleep are often referred to as non-REM or NREM sleep.)

During REM, your brain waves resemble those of waking rather than of quiet sleep.  The large muscles of your torso, arms and legs are paralyzed, although your fingers and toes may twitch.  You breathe quickly and shallowly; the flow of blood through your brain accelerates.  REM sleep is the time of vivid dreaming, and if wakened, you’d probably recall a fragment of a fantasy.

After about ten minutes in REM sleep, you descend the sleep staircase again.  The entire cycle of REM and NREM stages takes roughly 90 minutes.  Early in the night, the periods spent in the deepest stages of quiet sleep are longer.  In the second half of the night, REM sleep predominates.  By morning, you go around the sleep circuit four or five times.

This pattern changes gradually throughout life.  From infancy to adulthood, REM periods dwindle to less than a quarter of a night’s sleep.  By their thirties, men spend less time in the very deep stages of NREM sleep.  Women begin to sleep less deeply in their fifties.  By age 65, both sexes spend half as much time in deep sleep as they did when they were 25.  The lighter sleep stages increase later in life, and REM shrinks to about a fifth of total sleep time.

Individuals with chronic sleep problems that cause excessive daytime drowsiness, such as the breathing disorder called sleep apnea, may have so much difficulty with attention concentration or memory that they perform as if their IQs were ten points lower than they actually are.

Disrupted sleep and sleep disorders cost business as much as $70 billion annually in lost productivity, industrial accidents and higher medical bills, according to the Institute for Circadian Physiology in Boston.  Some times the toll is even higher.  Falling asleep at the wheel is second only to alcohol as a cause of car accidents.  In all, 200,000 to 400,000 collisions involving drowsy drivers occur each year and claim as many as 6,500 lives.

SLEEP PROBLEMS & DISORDERS

Sleep specialists have identified more than 100 different disorders of normal sleep, ranging from minor problems to life-threatening ones.

Insomnia.
About 33 percent of the population complains of insomnia at lease once in a year’s time.  Insomniacs typically experience less of the deepest, most restful sleep stages.  Sometimes troubled sleep is a sign of a troubled mind.  Virtually all persons with severe depression report difficulty falling or staying asleep; anxious individuals also can’t rest easily at night.  In such instances, the only lasting remedy to a sleep complaint is tackling the under-lying emotional problem.

Snoring.
One of every eight people snore, and men are more likely to sound off in the night than women.  If you snore or sleep with a snorer, remember that snoring happens most often when the sleeper in on his back.  The tongue falls backward over the throat opening, blocking the flow of air.  Nudging your partner onto his side should help.  Some desperate wives have placed a golf ball in a sock and pinned the sock to the back of their husbands’ pajamas.  When the men would roll over onto their backs, they’d feel so uncomfortable that they’d quickly switch to their sides.

Sleep Apnea.
This disruption of normal breathing during the night affects at least one of every 200 working-age men, who may wake hundreds of times in the night to breathe.  Sleep apnea causes debilitating side effects-headaches, chronic fatigue, and can be a cause of death.  An estimated 20 percent of all men over 50 suffer some degree of apnea.  The tip-off symptom is a pattern of ear-splitting snores, punctuated with pauses in breathing that last from 20 to more than 100 seconds.  If untreated, apnea can contribute to potentially fatal medical problems, such as high blood pressure, heart attacks or strokes.  Weight loss helps relieve apnea in overweight individuals.  Other treatments include continuous positive airway pressure or CPAP to keep the breathing passages open during sleep, and surgery to remove soft tissue at the back of the throat and enlarge the upper airway.

Periodic Leg Movement.
About 15 to 20 percent of sleep problems start in the lower limbs.  Some individuals jerk their legs just as they’re about to fall asleep.  Others kick their legs as they sleep--waking themselves and their partners.  Doctors do not know the precise cause of these movements, nor do they have a truly effective cure.  Tranquilizers or anti-seizure medications may help.

Sleepwalking.
Millions of people rise from their beds and wander through the night.  About 2.5 percent of all men and women walk regularly.  Children are even less likely to stay under the covers.  Between the ages of 5 and 12, 10 to 15 percent of children—with boys outnumbering girls—walk in their sleep at least once; six percent leave their beds once a week or more.

Sleepwalking always occurs during “slow-wave” sleep, the deepest stage of dreamless sleep.  In unknown ways, a malfunction of the brain’s sleep controls propels an individual from profound rest into a twilight zone of partial physiological arousal.  Sleepwalking seems to run in families.  Children inherit a genetic predisposition, not just to sleepwalking, but also to other problems of partial arousal from deep sleep, including sleep talking, bed wetting, and night terrors (episodes of waking up in a state of intense dread and anxiety).

Far rarer is a recently identified sleep disorder called episodic nocturnal wanderings, which may include extremely agitated behavior, such as screaming, dashing around, colliding with walls or attacking another person.

Sleep talking.
As many as one in every five persons sounds off during sleep.  Most of what they say makes little, if any, sense.  Most sleep talking occurs during the lightest stages of sleep and consists of a few brief words.  Someone who’s just fallen asleep may respond simply to queries, but true conversations are rare.  More often than not, sleep talkers seem to be muttering words like “okay” or gee” to themselves.

Bruxism or Teeth-Gnashing.
More than 20 percent of men, women and children grind their teeth at night.  Sometimes the reason is in the mouth, and dental repairs can help.  Sometimes the reason is in the mind.  One way to relieve the tension that leads to Bruxism is surprisingly simple:  Clench your teeth firmly for about five seconds and then relax for five.  Repeat four to six times a day.  In one study, 75 percent of bruxists stopped after 21 days of self-treatment.

Narcolepsy. 
Narcolepsy is a disabling, inherited disorder of the brain’s sleep-wake control mechanisms.  Regardless of how much they sleep at night, narcoleptics cannot stay awake during the day.  They doze off, not just while watching television or reading, but also while eating, talking or driving.  In addition to daytime sleepiness, narcoleptics develop problems sleeping at night, experience realistic and horrible sensations and hallucinations as they shift from wakefulness to sleep and back again and cannot move for several minutes after waking because of a condition called sleep paralysis.  Many also suffer from cataplexy, a partial or complete loss of muscle tone usually triggered by intense emotion or excitement.

Physical & Environmental.
Each individual has his or her own unique profile and requirements for sleep.  There are exogenous factors that contribute to your sleep that are generally external or environmental in nature, i.e. light, sound, temperature, etc.

Studies have concluded that 70% of all major body movements are followed by sleep shallowing.  These body movements have been shown to interfere with transition from intermediary sleep to deep sleep.  In fact, the absence of movement is generally necessary for a shift into deep sleep.  In short, as movement increases, depth of sleep decreases.  Studies show that poor sleepers experience 61% more movements than good sleepers.

Several characteristics of the sleep surface have been identified as having an effect upon the depth of sleep.  They are:  surface pressure equalization, postural support, motion transfer/partner disturbance, insulating qualities/temperature effects, and surface tactility/comfort.

            Surface Pressure Equalization
Because of gravity and weight producing pressure and stress on our body, we shift our weight from side to side to relieve pressure buildup.  When there is too much pressure applied to the skin, the blood supply to that tissue is cut off.  If the supply of blood is not restored to these high pressure points, tissue damage will result.  When we sleep, pressure over some arts of our body is high enough to restrict blood flow.  Our sleep is not only disrupted, but it also delays a return to a deeper sleep.
An even distribution of body weight with the sleep surface contributing support over a larger body surface area should be beneficial and perhaps give an individual a more restful period during recumbency.

There have also been studies done to determine the physiological reactions to the hardness of the sleep surface.  The studies showed that a hard surface elicited 46% more movements than an innerspring unit.  There was also a strong preference shown towards the soft and medium surfaces over the hard surface:  as expected, when the movements increased, the depth of sleep decreased.  The report concluded that surfaces have a statistically significant effect on depth of sleep.  It has been shown that approximately 30% of movement rate variance can be attributed to the sleep surface.

Postural Support
Millions of Americans suffer from low back syndrome, a condition in which the lumbar region of the back is in chronic pain.  Most people have this pain in the form of excessive muscle stress resulting from overexertion and extension.

Low back and neck are the most common bed-caused areas of discomfort upon arising.  When you sleep, your body contours should be in the same relaxed position they are in when you area standing up.  So there needs to be support underneath the low back and neck.  If there’s not, spinal ligaments can be stretched and the joints, which allow for movement of the spine, can be compromised.  These ligaments and joints are pain sensitive and when they are stretched and compromised for long periods of time, they may be damaged, causing pain and early morning stiffness.

Motion Transfer / Partner Disturbance
People are generally unaware of it, but they are actually disturbed by the bed motion created by their bed partners.  A high correlation has been shown between one partner’s shifting and the other partner’s shifting.  As a person’s threshold is lowered by sleep stage shifting, he is more easily disturbed by that motion.  Studies show that the nearer a person is to a period of body movement or stage lightening, the more quickly he will undergo that movement is he is disturbed by his partner.

Insulating Qualities / Temperature Effects
All of us at one time or another have been exposed to either too hot or too cold sleeping conditions.  It has been shown that temperature can prevent a person from sleeping, at either end of the tolerance range.  Unclothed, uncovered subjects will generally awaken from cold at 79 degrees or below.  Temperatures greater than 98.5 degrees cause excessive sweating and awakening.  Temperatures above 95 degrees reduce Stages 3, 4 and REM sleep.  Higher temperature also increases the pleasant feelings of dream content, but decreases intensity of dream emotion.

Researchers have found that an immediate surrounding temperature of 80.5 – 82.5 degrees, produces the longest and most restful sleep with the optimum amount of Stages 3, 4 and REM (slightly more than 10 degrees below skin temperature of 92.5 degrees).

Most sleep surfaces respond well to this, in that they allow heat to escape from the body at a controlled rate.  This provides the feeling that the bed is slightly cooler than the body.

Surface Tactility
Examples of poor surface tactility include non-breathable material, rough or unpleasant material adjacent to the skin, lumps and/or uneven surface and excessive surface hardness.  Sleep surfaces which offer some degree of softness and body acceptance while still offering support, are preferred.

Excerpts taken from “The Sleep Better, Live Better Guide” and “The Good Night Guide”, published by the Better Sleep Council.