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Medical How can some people stay healthy with just three hours sleep per day?

  1. Mar 26, 2008 #1
    From time to time we read about people who sleep three or four hours per day day. E.g. Thatcher, Churchill, Arafat, Edison etc. all slept just a few hours per day (about four hours if I remember correctly).


    So, it looks like most people who need 7 to 8 hours sleep are not sleeping efficiently. But then the question is why evoluton did not lead to more efficient sleep for most people? Is it because less efficient sleep leads to people spending more time in bed leading to more sex and thus more children? :smile:
    Last edited by a moderator: Apr 23, 2017
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  3. Mar 27, 2008 #2


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    How do you know they stayed healthy? We also don't know how much they slept TOTAL. Someone who sleeps only a few hours at night might be in the habit of a nap during lunch hour, for example. And, was this a lifelong habit, or just as they were older and/or while in office and just "toughed it out" for a few years until they could sleep and feel better again.

    Indeed, your quote that the person who only sleeps a few hours at night is consuming a lot of espresso (i.e., caffeine) indicates s/he is not getting enough sleep, but depending upon stimulants to remain awake during the day. I'd argue that if they got more sleep, they'd be able to think more clearly and work more efficiently during the day so wouldn't have to work as many hours to get the same work done.
  4. Mar 27, 2008 #3
    But if you can function with stimulants on the long term, your body is remaining stable. All you are doing is overruling a signal (sleepiness), just like a pilot will shut down an alarm signal if he is satisfied that it is false alarm. Maybe the brain needs 8 hours of sleep to function optimally, but the body could do with three hours.

    Another example:http://soucc.southern.cc.oh.us/home/jdavidso/Math/ErdosPaper.html" [Broken]

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  5. Mar 27, 2008 #4


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    The brain IS part of the body, and the body doesn't function at all without the brain. You're getting into rather speculative territory here that's NOT supported by sleep research.
  6. Mar 27, 2008 #5

    Erdös used amphetamines to work 19 hours per day. He lived longer than most of us will live. And he was one of the most productive scientists of the 20-th century. This suggests to me that sleep in most people isn't a very efficient mechanism.

    I'm not sure how sleep research is relevant here. All it could do is confirm what we all suspect: Trying to copy what Erdös did won't work for most of us, thus confirming my point: We need more sleep to recover than Erdös did.

    The question then is: why didn't we evolve to need less sleep? The amphetamines Erdös was using is irrelevant, that's a trivial thing for the brain to do. It is just a matter of sending signals to activate the body. The hard part is to make sure that the body is restored after only four hours sleep.
  7. Mar 28, 2008 #6


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    What is sleep? Simply a resting period and nothing more?

    Fairly soon the brain would develop a tolerance, and it wouldn't be effective anyway.
  8. Mar 28, 2008 #7
    Since this is in a science forum, a reasonable starting point for the layman might be here:

    The US Army once used speed to deal with sleepiness; Lurps sometimes stayed awake for four or five days. They found speed did not eliminate sleep deficit but rather postponed it.
  9. Mar 28, 2008 #8
    Yes, sleep is not a trivial "shutting down of the body". I've read that the reason why people who have worked too hard who get a "burn out" that lasts for years is because once you have exhausted your body, the recovery mechanisms don't work as well anymore (they cost energy too).
  10. Apr 12, 2008 #9
    Actually I would like to reverse your question. Sleep has evolved from not needing any sleep at all (bacteria, protists, unicellular eukaryotes, fish that dont sleep), to needing (in our case eight hours normally) which means that something more important than chasing girls over-weighed.

    This raises of course further questions - what determines how long we need to sleep? not intelligence (cats sleep more than we do and i usually outsmart my cat). brain/body ratio in sharks (which dont sleep) is approximately equal to that of primates. anyone who knows this?
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