Why do we sleep
From wikiWHYfiles
[edit] Introductory Note
Sleep is a natural state of bodily rest observed in humans and other animals. It is distinguished from quiet wakefulness by a decreased ability to react to stimuli, and it is more easily reversible than hibernation or coma. It is common to all mammals and birds, and is also seen in many reptiles, amphibians, and fish. In humans, other mammals, and a substantial majority of other animals that have been studied (such as some species of fish, birds, ants, and fruit flies), regular sleep is essential for survival.
[edit] Reason
Sleep used to be studied by behaviorists. Their theories of what sleep is focused upon behavior. This prevented sleep from being understood because sleep is not behavior at all. Sleep is a metabolic requirement. Recently sleep has begun to be understood at the metabolic level, at the level of cellular activity. At its most fundamental level, sleep seems to be a metabolic imperative. One guest below has suggested that sleep may well be the 'default' mode of life itself and that being awake is little more than a daily period of heightened awareness of one's surrounding which is especially suited to doing things like finding food and reproducing. Indeed, the question "Why do we wake up" makes much more sense than the question "Why do we sleep". "Why do we wake up" is an easily answerable question, too. For one thing, the body's metabolic system shifts into the catabolic phase.
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[edit] More
- The record for the longest period without sleep is 18 days, 21 hours, 40 minutes during a rocking chair marathon. The record holder reported hallucinations, paranoia, blurred vision, slurred speech and memory and concentration lapses.
- It’s impossible to tell if someone is really awake without close medical supervision. People can take cat naps with their eyes open without even being aware of it.
- Anything less than five minutes to fall asleep at night means you’re sleep deprived. The ideal is between 10 and 15 minutes, meaning you’re still tired enough to sleep deeply, but not so exhausted you feel sleepy by day.
- Dreams, once thought to occur only during REM (Rapid Eye Movement) sleep, also occur (but to a lesser extent) in non-REM sleep phases. It’s possible there may not be a single moment of our sleep when we are actually dreamless.
- Some scientists believe we dream to fix experiences in long-term memory, that is, we dream about things worth remembering. Others think we dream about things worth forgetting – to eliminate overlapping memories that would otherwise clog up our brains.
- Scientists have not been able to explain a 1998 study showing a bright light shone on the backs of human knees can reset the brain’s sleep-wake clock.
