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Why do people sleep?

  1. Sep 14, 2007 #1
    It is no mystery of what sleep is, but no one has been able to figure out WHY people sleep. This thread is here to ask people why they think sleep is needed.


    I believe that it is because the small amount of voltage required to run the human body required...power. Generally, food is that power. I believe sleep is the portion of the day in which the food in the body has not been converted into power yet and the body needs to temporarily shut down during the process.
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  3. Sep 14, 2007 #2
    Sleep is needed to allow the conscious part of the brain and the unconscious part of the brain to communicate and rebalance. This helps keep brain activity stable.
  4. Sep 14, 2007 #3

    Math Is Hard

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    Note: moved thead from Philosophy to Biology. - MIH
  5. Sep 15, 2007 #4
    Because, I suspect from an evolutionary viewpoint, for millions of years we had no light at night and no way to see at night so we adapted- evolved a sleeping cycle like most mammals or a period of rest which was more productive than evolving night vision i guess, even if we had why hunt or gather in the dark when it's easier and more productive in the day? Another thing to consider is that by sleeping we most likely have more energy during the day rather than not sleeping at all or very little. Probably explains why a few of us are night owls, we kept watch over everyone else while they slept and then slept until high noon while everyone else got up and called us lazy until their legs got nawed off by a bear. Dreams are probably mostly random firings of the cerebral cortex or cells still ghost firing that were used greatly during the day and cementing learning, all activity in the brain can't cease entirely.
  6. Sep 15, 2007 #5


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    I am fairly confident that the sleep cycle has more to do with the brain's need to process the day's input. Experiments with sleep deprivation tend to show worse neurological aberrations than physiological aberrations.
  7. Sep 21, 2007 #6
    An interesting wrinkle in this is that Circadian Rhythms make just about everything from birds to us more prone to sleep between the hours of about 2 and 5 in the morning. Arachnologists are quite upset by this, because evolution, therefore, favored spiders that built their webs during those time periods; fewer of them were eaten during web construction, when they were vulnerable, because most creatures that would eat them were sleeping.

    Arachnologists are upset about it because they have to be awake to observe web building during a time when they would rather be asleep (the arachnologists, not the spiders).
  8. Oct 7, 2007 #7
    The linked site, although several years old, lays out most of what is currently known about the effects of NOT sleeping. The short answer is that if one doesn't sleep, one dies rather quickly.
    http://www.nhlbi.nih.gov/health/prof/sleep/res_plan/index.html [Broken]
    Last edited by a moderator: May 3, 2017
  9. Oct 7, 2007 #8


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    They'll find kindred spirits in the astronomers...
  10. Oct 9, 2007 #9
    I agree with both sd01g and jammieg. One has to sleep to keep brains activity stable, thats why when you don't sleep for a long time it has the same affects of being drunk, but it also has to do with our sensitivities to light, which is an evolution thing.

    But don't we also sleep to repair our bodies? When one sleeps metabolism slows down right? Therefore giving time for the body to repair itself. When one is awake and active, our metabolism is constantly working, overworking our bodies. I heard that fasting is actually really good for ones health(If you do it once in while,not daily) because it refrains the stomach from overworking to digest food. I mean isn't that the reason why we get sick and old, it's because our bodies are constantly overworking itself causing it to breakdown.
  11. Oct 9, 2007 #10
    I think a more interesting way to phrase the question would be... why did species that sleep evolve in the first place? What evolutionary advantage did sleep give?

    In that case, I think it's a matter of energetic efficiency. At some point in our ancestors' past, inducing a state of minimal activity and energy use was probably better in the long run than trying to find food or a mate in the darkness. This probably created a niche for other species (spiders) to gain an advantage from being nocturnal.

    I think we just carry it as part of our evolutionary past... I'm quite confident that, if it had been better, complex life would have evolved without the need to sleep.
  12. Oct 10, 2007 #11

    jim mcnamara

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    There are complex species that do not require sleep at night. Rodents are active for about 1 hour out of four around the clock.

    But Proggle has it. Sleep is an evolutionary leftover, that we later adpated to help "re-program" our larger brains. There are nocturnal and diurnal primates, but great apes are all diurnal.
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