Reading(1)from BBC - 达人(昕昕)

2005/11/01 | Reading(1)from BBC
类别(冷藏的宝库) | 评论(2) | 阅读(36) | 发表于 14:50: Sleep deprivation
What if restless nights are normal instead of the exception?

It's important to explore why we sleep in order to set aside our tossing and turning. Sleep deprivation isn't just bad for us, it's also bad for people around us: tens of thousands of traffic accidents are attributed to sleepy drivers every year, and lack of sleep was also blamed for the Exxon Valdez oil spill in 1989. But the average night's sleep in the UK now averages about 90 minutes less than it did in the 1920s, when it was nine hours a night.

Sleep researcher Dr William Dement estimates that up to 95 per cent of Americans suffer from lack of sleep at some point in their lives. According to Dement, sleep deprived people are less happy and more stressed than those getting eight hours' downtime at night. He says: "I consider sleep deprivation a national emergency." The effects? Physical frailness, as well as mental and physical exhaustion.

What is sleep?
Sleep is made up of different stages. The ten-minute period of light sleep (drifting off from wakefulness) is called Stage One. Stage Two is deeper and lasts about 20 minutes. Stages Three and Four come after this, and are types of deep sleep.

Deep sleep is the part of sleep that our body and brain needs to recover from the day. It's sometimes called delta sleep, after the delta waves the brain generates. We don't dream during this time. After about 90 minutes of deep sleep, REM sleep - including rapid eye movement - begins. During a normal night, people usually cycle through the various stages several times. Problems arise when the pattern of cycles is broken.

Researchers at Loughborough University's Sleep Research Laboratory have found that people are designed for two sleeps a day - the main one at night, and a nap in the afternoon. This suggests that an afternoon siesta, as people in warmer parts of the world have, may be a physiologically good idea.

Are we getting enough?
Those of us who don't have the luxury of an afternoon nap still tend to get sleepy at about this time. Interestingly, people who increase their night-time sleep find that this afternoon 'dip' disappears. A ten-minute nap at lunchtime is just as effective.

Sleep problems, including dozing off, can be a symptom of many other conditions, from problems with the thyroid gland to depression - and even occasionally rare sleep disorders such as narcolepsy. So it's important to speak with your GP if you're currently experiencing insomnia or another sleep problem, since it could be indicative of another condition.

The Loughborough University team found that sleep restrictions can be therapeutic for severely depressed patients. Cutting back on sleep to fewer than four hours for one night often results in a dramatic improvement of mood, with the depression lifting rapidly, albeit leaving the patient sleepy. Unfortunately, this remarkable effect lasts only for as long as the patient continues to remain awake, as the ensuing sleep usually leads to the return of the depression.

Sleep and mood are interlinked in intriguing ways that are still not understood. But a satisfying sleep, like a satisfying meal, can leave one happy and content - with room perhaps for just a little more!

Remember to make your bedroom a special room, used primarily for sleeping - making it as comfortable, airy and dark as possible.; 0

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