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Home > Products > Article - Excerpts from Getting a Good Night's Sleep
Excerpts from Getting a Good Night's Sleep
by Muriel MacFarlene R.N, M.A.
Why We Sleep - the Purpose and Function
Webster's Revised Unabridged Dictionary defines sleep "as a natural state of rest during which consciousness of the world is suspended." That definition doesn't tell us much about what happens while we sleep and why we appear to need it.
If you wonder what happens during that "natural state of rest" it might be helpful to know that your brain is directing your body to heal and repair worn-out cells and tissues; rebalance chemicals needed for a variety of physical and mental activities, and your immune system is making cells that fight infection. In an article in the journal Cell researchers report they have evidence that sleep influences the consolidation of recent memory. Information acquired while you are awake is actively altered, restructured, and strengthened while you sleep. Your brain is organizing and storing recently learned information and experience into memory and getting you ready to wake up energized, invigorated, and rejuvenated with recently learned information available for recall.
If you slept well, you should be ready, with your battery charged, to take on the demands of a new day. But if you didn't sleep at all or slept poorly, and didn't find that natural state of sleep at all, then you are probably going to wake up feeling physically exhausted, irritable, and far from ready to meet the burden your new day may represent.
Why Head for the Land of Nod?
Just think about it. According to a Census Bureau report for the year 1998, the life expectancy for men in the U.S. is 72.9 years and for women, 83.3 years. So you are going to lie down, pass into unconsciousness for brief periods that will add up to one third of your life; for men that is more than 24 years and for women, almost 28 years, or an average of 205,000 hours in a 70-year plus lifetime. Why would we want to be unconscious and vulnerable to all kinds of danger if there was no logical reason or benefit to do so?
The caveman must have worried about tigers and bears, oh my, as well as all kinds of other intruders into the entrance of his cave, an entrance it was not possible to close off without rolling a gigantic many-ton boulder into that space. Householders and travelers of all periods, who slept where they found themselves when night fell, must have worried not only about robbers, thieves and muggers, and all other kinds of marauders, but spirits, demons, and a variety of denizens of the night who could use the cover of darkness to attack. Today, lions and tigers and bears probably don't rank high among things we worry about, but there are many other potential troubles that can assault any one of us, both while asleep or awake. Un-thought of by the sleeper of a century ago: nuclear war, airplane accidents, terrorists, identity theft, aging, and health insurance woes can create worry and stress. No wonder you may be lying awake, feeling your heart beat, listening to the small sounds any house makes that you never hear during the daytime; and worrying.
If you're grumpy and irritable when you don't get a good night's sleep, but also think the idea of devoting years of your life to lying around unconscious seems to be a big waste of time, when you could be out partying like a rock star or accomplishing all kinds of tasks; winning the Nobel Peace Prize, writing the great American novel, or just getting the laundry done, then you need to know what science says are some of the reasons you absolutely need sleep.
The National Institute of Neurological Disorders and Stroke reports that animal studies show sleep is necessary for survival. Whoa! That statement seems serious enough to get anyone's attention.
Rats that normally live three years, when deprived of REM sleep, only lived about five weeks and those deprived of all sleep stages only lived about three weeks. These rats developed abnormally low body temperatures and sores on their tails and paws, pointing to an impaired immune system.
Too little sleep leads to impaired memory and physical performance. If sleep deprivation continues, hallucinations and mood swings develop. It is believed that sleep gives neurons a chance to shut down and repair themselves. Without sleep, neurons may become so depleted of energy or so polluted with the byproducts of normal cellular activities that they malfunction. It also gives the brain the time to exercise important neuronal connections that could deteriorate if not used. Every government has always known that sleep-deprived prisoners will give up closely held information to their jailers just to be allowed a few hours of sleep.
During deep sleep children and adults release growth hormone. Children need the hormone to grow and adults to help repair and renew a variety of tissues. Proteins are the building blocks needed for cell growth and repair from damage caused by things like stress and ultraviolet rays, and many of the body's cells show increased production and reduced breakdown of proteins during sleep.
Sleep is a time when nerve-signaling patterns are repeated, helping to encode memory and improve learning. In addition, activity in parts of the brain that control emotions, decision-making and social interactions are reduced, suggesting that this will help you maintain optimal emotional and social functioning while you are awake.
If you feel grumpy and irritable when the checkout line at he grocery store doesn't move fast enough, that might be a clue that your lack of sleep is affecting your mood, and getting help to find a solution to your sleep deprivation might make a difference for you and the poor clerk who has to deal daily with you and the millions of others who suffer from lack of sleep. Almost every medical condition can create a simultaneous sleep problem, known as secondary insomnia, so it just makes sense to examine your sleep, particularly if you are having more than just a temporary spat of insomnia.
If You Don't Snooze You Lose
So just what happens when you go to sleep? Researchers state that there are two mechanisms that activate sleep:
- 1. The length of time since the individual last slept. For the majority of people, once you have been awake for 12 hours, your body begins to slow down and you become less alert. You may begin to feel drowsy, you might feel the need to yawn or stretch - your body is beginning to indicate your need to sleep. If you continue to stay awake, for whatever reason, as you reach 24 hours without sleep, your body wants and needs sleep. It may even demand sleep. Your eyes begin to close, whether you want them to or not, and you may find yourself nodding off, no matter what you are doing - driving an 18-wheeler on a ten lane wide interstate or sitting comfortably in your recliner in front of the TV.
When you are roused from that little mini-sleep, by honking horns and rude gestures, or being shaken and told to get out of the chair and go to bed, you probably wonder why you can't fall asleep that easily when you put your head on the pillow and then find yourself staring at the ceiling.
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2. Your biological or internal clock. There is an internal clock in diurnal (day-time) mammals - even if you didn't know it, you and all humans are diurnal. (Warm-blooded, programmed to be awake and active during daylight hours and to sleep during dark or nighttime hours.) This is one of the biological clocks known as circadian rhythm (Latin for "about" (circa) and "daily" (dies)).
Most of us are aware of the other type of creatures, known as nocturnal, such as bats, owls and the ordinary house cat, all of whom go out to hunt when it gets dark and sleep during the day. While many of us try to be nocturnal, our internal rhythms are programmed for us to be awake while it is light.
There are other biological clocks, other than the circadian one, that govern things like the migration of birds, the hibernation of bears, and the fertility cycles of a variety of creatures, including humans.
Do You Have Rhythm (Circadian, that is)?
Circadian rhythm initiates a number of biological activities such as hormone productions, glucose levels, blood pressure, waking and sleeping. It determines the daily activities of all living things, from the sunflower in your yard to human beings, and it is governed by one rotation of the Earth. Charles Czeisler, professor of medicine at Harvard Medical School, states that each person's internal clock runs on a daily cycle of 24 hours, 11 minutes, and individuals vary from this norm by no more than plus or minus 16 minutes.
However, it is capable of resetting itself as needed. It is governed by light and therein often lays the problem. Light comes in your eyes, travels along some fibers from the optic nerve directly to a tiny cluster of nerves, deep within your brain, in the area known as the hypothalamus. This hypothalamus, known as the suprachiasmatic nucleus or SCN responds to changes in your environment - not just seasonal differences or traveling across time zones, but all kinds of artificial light, which can disrupt your normal circadian rhythms.
In the evening when it begins to get dark, in response to the lack of light, another small pea-like brain structure, the pineal gland, is turned on by the SCN and begins to produce and release a natural hormone, melatonin, into your blood. This ordinarily occurs around 9 p.m. and most people begin to feel less alert. Melatonin levels in the blood stay elevated for about 12 hours and the light of a new day makes them drop off until they are barely detectable.
Before electricity, most people went to sleep when it got dark and got up again when it got light.
However, even if the pineal gland is switched on by nightfall, it will not produce melatonin unless you are in a dark or dimly lit environment. So 24-hour fluorescent-lit convenience stores, gambling casinos, sitting in front of the TV or a computer screen late at night; night shifts in hospitals, factories, airports; late night dance clubs with pulsating flashing neon, all places with artificial light interfere with the production of what might be called nature's sleeping potion, melatonin. In fact, if you are sleeping and wake up during the night and turn on the lights for whatever reason, to find your way to the bathroom, to look for a sleeping pill or a pain pill, or take the dog out, you may be unintentionally resetting your biological clock.
We sleep to repair and restore a variety of body systems and parts, and while you are sleeping and your body is actively doing all this marvelous repair and rebuilding work; your brain is busy too.
Recent scientific evidence supports the time-honored advice to students cramming for exams to get a good night's sleep after they study and before the next day's exam. Researchers who analyzed brain activity in sleeping volunteers who had learned to navigate their way through a computer-generated virtual town discovered that their memory of how to do it is strengthened and stored during deep sleep, and that is shown by improvement in performance on the next day's test.
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