Sleep Apnea

Sleep Apnea, Why Do We Sleep ?

Posted on 06. Dec, 2009 by admin in Sleep — Normal and Abnormal

Nobody knows exactly why we sleep. At one time people thought that sleep was just a rest period for our brains. Then polysomnography was developed. This technology allows scientists to make electrical recordings of brain activities during sleep. Scientists were surprised to discover that brains are anything but idle during the night.

Some theories suggest that we sleep to overcome body fatigue. Our bodies do seem to overcome fatigue during sleep, but studies have shown that it is our brain, not our muscles, that requires sleep in order to feel rested and function normally.

How much sleep do we need? Actually there is no “normal” amount of sleep that is right for everybody. The amount of sleep a person needs is a very individual matter and also varies according to age and circumstances (Figure 3.1).

It used to be said, for example, that babies needed 21 hours of sleep per day, but now it is known that the amount of sleep they need varies a great deal from infant to infant. Sixteen-year-olds seem to need approximately 10 or 11 hours, and this decreases to about eight hours for an average adult. There are cases of healthy, alert adults who do fine on four hours of sleep, but that is rare. The record for habitually short sleep seems to be about three hours per night. No one has ever been documented to need no sleep.

What happens if people are experimentally deprived of sleep for several days? Sleep deprivation upsets the body’s physiologic systems: hormones, immune system, blood pressure regulation, digestive system, and urine production. Normally our physiologic processes go through 24-hour ups and downs. Sleeping and waking up in the morning are signals that our biological clock uses to keep those physiologic systems synchronized with each other. A person who is not sleeping well or whose sleep schedule is irregular (for example, because of shift work) does not have normal signals to reset his clock each day and keep things running smoothly. This may help to explain why disturbances of the digestive system, headaches, and other illnesses are more common in people who do shift work.

In terms of behavior, sleep-deprived people have periodic bouts of drowsiness when their built-in biological clock tries to get them to go to sleep. They suffer a gradual, increasing loss of the ability to concentrate, and their ability to think becomes dull. These effects on thinking and memory are especially damaging in school-aged children and teenagers, many of whom are seriously sleep-deprived.

Sleep-deprived people also may become irritable and disoriented, and may have dreamlike hallucinations. Reactions become slow and erratic. In a sleep-deprived driver, this condition commonly leads to auto accidents. Research shows that even as many as seven hours of sleep for seven nights in a row can slow a person’s reaction time and interfere with tasks such as driving. Nine hours of sleep are needed, consistently every night, for reaction time to be at its best.

In itself, sleep deprivation is not fatal. However, it certainly causes fatalities when it interferes with a person’s ability to perform normally. When a long-haul truck driver falls asleep at the wheel and crashes, an average of four innocent victims die with him.

To be at our best, each of us needs a certain quantity of sleep every night. If we do not get enough sleep, we tend to build up a sleep “debt.” This leads to a tendency to feel drowsy during the day and to fall asleep more readily.

But the quantity of sleep we get is not the whole story. Equally important is the quality of our sleep. Does it come in large, continuous blocks, or is it fragmented into short naps? Do we get enough “deep” sleep?

In people with sleep apnea, sleep is broken up by numerous awakenings during the night, reducing the quantity of sleep they obtain. In addition, the numerous awakenings break up the structure, or continuity, of their sleep. They miss out on some of the normal stages of sleep. This lowers the quality of their sleep. Thus sleep apnea affects both the quantity and the quality of sleep. Let’s look a little more closely at what goes on in your brain while you are sleeping.

Related posts:

1. Sleep Apnea, The Stages of Normal Sleep After you go to sleep, the activities of your brain and body settle into fairly predictable patterns. Sleep researchers...
2. Sleep Apnea: A Silent Killer Getting a good night sleep is essential for your well-being. However, many people don’t realize that they are often sleep-deprived...

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