# Why do we sleep? **URL:** \ **Category:** Great Debates\ **Created:** [December 8, 2006, 12:09pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327 "2006-12-08T12:09:54Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![yelimS](https://avatars.discourse-cdn.com/v4/letter/y/54ee81/32.png) [@yelimS](https://boards.straightdope.com/u/yelimS)\ **Post date:** [December 8, 2006, 12:09pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/1 "2006-12-08T12:09:54Z")
I just read a short article that said the theory about sorting the new impulses was still predominant. Problem is, I can’t really see how this accounts for my favourite animal, The Almighty Koala (Sleepier than the sloth!). Actually, I can’t see how it would be especially useful for anyone, except modern man. Was life really so diverse 10,000 years ago that we needed seven hours **each night** to sort these new impulses? Is it now, for monkeys? If it’s for saving energy during dark hours, why don’t we save just a little less to stay alert and watch out for predators? If it’s for “recharging the batteries”, why do koalas need 20 hours and horses only four? ---
**Author:** ![tmaareif](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@tmaareif](https://boards.straightdope.com/u/tmaareif)\ **Post date:** [December 8, 2006, 12:32pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/2 "2006-12-08T12:32:38Z")
I came up with a wierd theory recently, and I want to share it with you guys: Hypothesis: Sleep evolved in animals because it provides their conscious brains with an escape from the crappiness of existence. To me, that explains why lower life forms on the evolutionary scale sleep less than ones higher up (less consciousness = less need for escape). And it explains dreams- they are tv/escapism for higher-on-evol.-scale animals like koalas and dogs and other mammals even higher up such as apes and humans, long before tv and storytelling was invented. Okay, I’m about to get slapped. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 8, 2006, 12:35pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/3 "2006-12-08T12:35:52Z")
There is no such evolutionary scale. ---
**Author:** ![tmaareif](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@tmaareif](https://boards.straightdope.com/u/tmaareif)\ **Post date:** [December 8, 2006, 12:47pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/4 "2006-12-08T12:47:02Z")
[QUOTE=Mangetout] There is no such evolutionary scale. [/QUOTE] I know that it’s a myth to say that animals ‘evolve(d) upwards’, because evolution just goes forwards, sometimes making animals faster and smarter and sometimes making them slower and dumber. But I was under the impression that, generally, as you moved down the line of evolution from earliest life to humans, you generally see more ‘consciousness’ and intelligence in animals. For instance, a beetle, while very smart, cannot feel anger and joy like a dog can. Dogs pale in comparison to humans. Pigs pale in comparison to dogs. Rats pale in comparison… Is there any truth to that? ---
**Author:** ![yelimS](https://avatars.discourse-cdn.com/v4/letter/y/54ee81/32.png) [@yelimS](https://boards.straightdope.com/u/yelimS)\ **Post date:** [December 8, 2006, 1:08pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/5 "2006-12-08T13:08:28Z")
I can’t see any sense in it. Advanced brains are useful to some, too costly for others. I assume that if you looked at **our** ancestors, there would be a general trend towards more advanced brains (though it’s not at all impossible that mental capabilites have regressed at times to save resources), but keep in mind that evolution is mapped out as a tree, not a line. If there were, at all times, only one evolutionary trend for each attribute (eg, bigger brains), then there wouldn’t be much more than one species at a time. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 8, 2006, 1:34pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/6 "2006-12-08T13:34:14Z")
[QUOTE=tmaareif] I know that it’s a myth to say that animals ‘evolve(d) upwards’, because evolution just goes forwards, sometimes making animals faster and smarter and sometimes making them slower and dumber. But I was under the impression that, generally, as you moved down the line of evolution from earliest life to humans, you generally see more ‘consciousness’ and intelligence in animals. For instance, a beetle, while very smart, cannot feel anger and joy like a dog can. Dogs pale in comparison to humans. Pigs pale in comparison to dogs. Rats pale in comparison… Is there any truth to that? [/QUOTE] I understand what you’re trying to say, but since beetles, dogs, pigs and rats are not evolutionary ancestors of humans, even the forwards/backwards thing makes no sense. If you go far enough back in evolutionary time, yes, everything was generally simpler (to the extent that consciousness was not even possible in any extant lifeform), but that’s really just because of the incremental nature of biological development. ---
**Author:** ![tmaareif](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@tmaareif](https://boards.straightdope.com/u/tmaareif)\ **Post date:** [December 8, 2006, 1:50pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/7 "2006-12-08T13:50:41Z")
That sorting-the-new-impulses idea is brilliant. My dreams always consist of a story that ties together ‘new impulses’ in clever ways- plus, as I slowly awake from sleep, I often have what I call Flashes of Brilliance: I figure something out that, if I hadn’t had that subconscious time of reflection, I wouldn’t have. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 8, 2006, 1:52pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/8 "2006-12-08T13:52:24Z")
[QUOTE=tmaareif] That sorting-the-new-impulses idea is brilliant. My dreams always consist of a story that ties together ‘new impulses’ in clever ways- plus, as I slowly awake from sleep, I often have what I call Flashes of Brilliance: I figure something out that, if I hadn’t had that subconscious time of reflection, I wouldn’t have. [/QUOTE] I can do the same by getting slightly drunk; that doesn’t necessarily mean that it’s somehow meant to be that way. ---
**Author:** ![tmaareif](https://avatars.discourse-cdn.com/v4/letter/t/bcef8e/32.png) [@tmaareif](https://boards.straightdope.com/u/tmaareif)\ **Post date:** [December 8, 2006, 2:13pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/9 "2006-12-08T14:13:29Z")
[QUOTE=Mangetout] I can do the same by getting slightly drunk; that doesn’t necessarily mean that it’s somehow meant to be that way. [/QUOTE] Also, getting high on Robotussin or acid really gets your juices flowing. And Sherlock Holmes used heroin to bring out his deductive genius. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 8, 2006, 2:15pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/10 "2006-12-08T14:15:22Z")
[QUOTE=tmaareif] … And Sherlock Holmes used heroin to bring out his deductive genius. [/QUOTE] It was cocaine, I think (possibly opium too), but… …Sherlock Holmes is a character in _fiction_. ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [December 8, 2006, 2:30pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/11 "2006-12-08T14:30:26Z")
We sleep because there are two other parallel earths. My counterparts take over while I’m having a snooze. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 8, 2006, 2:33pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/12 "2006-12-08T14:33:24Z")
[QUOTE=chowder] We sleep because there are two other parallel earths. My counterparts take over while I’m having a snooze. [/QUOTE] You spend twice as long asleep as awake? ---
**Author:** ![yelimS](https://avatars.discourse-cdn.com/v4/letter/y/54ee81/32.png) [@yelimS](https://boards.straightdope.com/u/yelimS)\ **Post date:** [December 8, 2006, 3:38pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/13 "2006-12-08T15:38:07Z")
[QUOTE=Mangetout] It was cocaine, I think (possibly opium too), but… [/QUOTE] Cocaine and _morphine_. ---
**Author:** ![Mangetout](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mangetout/32/19_2.png) [@Mangetout](https://boards.straightdope.com/u/Mangetout)\ **Post date:** [December 8, 2006, 3:45pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/14 "2006-12-08T15:45:55Z")
Didn’t he hang out in an opium den in one story? ---
**Author:** ![yelimS](https://avatars.discourse-cdn.com/v4/letter/y/54ee81/32.png) [@yelimS](https://boards.straightdope.com/u/yelimS)\ **Post date:** [December 8, 2006, 3:58pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/15 "2006-12-08T15:58:01Z")
It’s been a long time since I read the books, but according to wikipedia, he posed as an opium addict once. The drugs he’s famous for doing, however, are cocaine and morphine. This, of course, is essential knowledge. 😃 ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [December 8, 2006, 4:32pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/16 "2006-12-08T16:32:26Z")
[QUOTE=Mangetout] You spend twice as long asleep as awake? [/QUOTE] Not at all, I have two counterparts. We each have 8 hour shifts…so to speak ---
**Author:** ![RickJay](https://avatars.discourse-cdn.com/v4/letter/r/bb73d2/32.png) [@RickJay](https://boards.straightdope.com/u/RickJay)\ **Post date:** [December 8, 2006, 4:44pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/17 "2006-12-08T16:44:03Z")
Another popular theory is that most animals, such as humans, have a diurnal or nonturnal cycle and that sleep encourages them to lay low and out of trouble during the period of the day/night cycle they’re most at danger. Humans (or our ape ancestors) don’t do so well at night; we’re daytime animals. Natural selection would select against individuals who wandered around at night when they could fall off a cliff or get eaten by a tiger. ---
**Author:** ![Khadaji](https://avatars.discourse-cdn.com/v4/letter/k/9e8a1a/32.png) [@Khadaji](https://boards.straightdope.com/u/Khadaji)\ **Post date:** [December 8, 2006, 5:07pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/18 "2006-12-08T17:07:31Z")
The following is conjecture on my part. I believe that we sleep so that the brain and body can create important chemicals that the brain needs - seratonin for one. I believe that the creation of seratonin causes our dreams. I have no cites for the following. I have read that seratonin is created during REM sleep. I have read that if you disrupt REM sleep repeatedly it is detrimental to one’s physical and mental health. I have takend 5-htp (a precursor to seratonin) and it seems to cause very intense dreams. It also seems to allow me to need less sleep. This is a sample-set of one, there is no rigorous scientific testing and it is possible that my conjectures are wrong. ---
**Author:** ![marshmallow](https://avatars.discourse-cdn.com/v4/letter/m/df705f/32.png) [@marshmallow](https://boards.straightdope.com/u/marshmallow)\ **Post date:** [December 8, 2006, 5:48pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/19 "2006-12-08T17:48:12Z")
[QUOTE=tmaareif] Pigs pale in comparison to dogs. [/QUOTE] Since when? ---
**Author:** ![chowder](https://avatars.discourse-cdn.com/v4/letter/c/977dab/32.png) [@chowder](https://boards.straightdope.com/u/chowder)\ **Post date:** [December 8, 2006, 6:49pm UTC](https://boards.straightdope.com/t/why-do-we-sleep/383327/20 "2006-12-08T18:49:25Z")
Can anyone tell me why cats can sleep and sleep and sleep and… They wake occasionally to eat and answer the call of nature, then exhausted after all this activity, they go back to sleep. I wanna come back as a cat. [Next page](https://boards.straightdope.com/t/why-do-we-sleep/383327.md?page=2)