h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

You know, sleeping is a pretty strange process for anything to do at all... anything with teeth can come up and chomp on your leg while you're asleep, yet it's a necessary part of life, and not for the reasons you'd expect.
It's not to regenerate cells, like we once thought; while resting and not sleeping you regenerate cells at the same rate as you would while sleeping. What, then, makes sleep necessary? Dreams.
Rats that were woken up as soon as they reached REM sleep were tested against rats who weren't given food to see which would live the longest. The starved rats won, and I suppose that they were later killed or something because the scientists didn't need them anymore. They never really mention what happens to the rats in the reports. Maybe the scientists give them to biology classes for disection; that would be resourceful, unless we're talking about tests where they try out new diseases on rats.
Anyway, has anyone heard any theories on why we need dreams more than food? I've read that there's a theory out there that we need dreams because our brain is re-organizing its memories; deciding what stays and what leaves, much like computers. I can't remember exactly where, which makes that very questionable evidence; if anyone else has heard the same, or has anything to add to this, please reply. That probably goes without saying, but hey, this is my first post, cut me some slack.

I've heard the same thing as you, but it was mostly in the form of speculation in books where the general consensus was "We don't really know."

It seems to make sense when you consider the fragments of recent events that creep into dreams. But then often dreams seem to have nothing at all to do with reality.

You say that dreams make sleep necessary, but a large portion of the time we spend sleeping is not time spent dreaming. So it seems that there must be other reasons sleep is necessary as well.

This is my first post too

I think we can begin by asking an obvious, though overlooked question:
To what mythological region, to what Gods, do dreams belong? The assumption in the question is: were we to know "where" dreams belong, then we would know better what they want, what they mean, and what we are to do with them. In James Hillman's "The Dream and the Underworld" (which I strongly recommend to fully pursue the subject)the dream is placed in the context of myth, with dreams belonging to the Underworld and its Gods (notably, Hades). Even Freud turned to the mythical underworld to ground his theory of dreams (see Thanatos).

According to the research I had to do recently, NREM sleep is to rest the body and REM sleep is to rest the mind/brain. The reason that dreams can be very surreal but the dreamer believes unquestioningly about the sheep in the office block, is because the part of the brain that controls reason is shut off. About 20% of time spent asleep is spent in REM sleep although it seems like less as we don't remember all of our dreams. Interestingly, babies and very young children spend more time in REM sleep, it is thought that they need this extra time as their brains are still developing and it helps them to develop. It is believed that time spent in REM sleep decreases with age and that the elderly spend little or no time in REM sleep.

If you really want to know the effects of sleep loss, try not sleeping for a few days, then you'll see just how important sleep is. It's not just rats it effects. Enforced wakefulness over an extended length of time will cause psychosis as well as muscle fatigue. I believe it was a DJ in America who tried this as an experiment and it changed his whole personality permanently. He went from being outgoing and funloving to leaving his family, becoming withdrawn and paranoid. The effects were irreversible. A man in Britain suffered from an extremely rare illness that destroyed the part of the brain responsible for going to sleep. Over a few maonths his physical and mental condition deteriorated, he suffered memory loss and confusion and eventually died.

In answer to the point about sleep being impractical because an animal could gnaw on your leg while you were dosing, the reticular activating system in the brain continues environmental monitoring while asleep. How often do you wake up when you hear an unusual noise, or even when the alarm goes off? Humans don't need to worry so much about environmental monitoring but have you noticed how dogs and cats prick their ears when asleep if they hear a noise?

Hope this answers some of the questions.

there's a theory stating that sleep is actually a legacy of our cold-blooded ancestors, the reptiles: they had to kinda "switch off" at night because they didn't get enough energy to run around. us mammals are luckily enough capable of a decent nightlife, but we got stuck with that darn biorythm thing anyhow. but then again - it's just a very hard-to-proove theory.

not sleeping AT ALL (no micronaps, etc.) is said to cause hallucinations and the like, and sleep deficit seems to lower one's IQ temporarly. one's selfjudgement also seems to suffer.

BTW: the brain has some very cool mechanisms to avoid that some little furry creatures nibble off our legs while we're sleeping: our sensory organs remain relativly active, and have the possibility to wake us up if any danger seems to be emminent - just watch a cat's ears while it's sleeping. might sound a bit banal, but if zou think about it it's actually cool: the brain never really detaches itself from the outside world.

and, last but not least, some research seems to show that we kinda shift the stuff we got as input during the day into our long-term-memory-banks using dreaming - it seems to be a way of filtering and post-processing thing. but it's just a theory, and please don't quote me on that one.

have fun,

- schweini

My theory is that most people don't do what they really want to do in their waking dream (life). If it is impossible to live out your fantasies or explore other possibilities other than your daily grind, what reason is there to want to go on living anyway?

I heard a pretty interesting theory from somewhere I cant remember, but it goes like this. Theres a section of our brain that acts like a barrier between what we imagine and what is real. This barrier needs rest, so the theory goes, and If it doesnt get rest then it becomes harder and harder to seperate what we imagine and what is real which is consistant with what I have seen happen to people who dont get enough sleep. Weather this holds any validility I dont know, but it sounds good.

I heard a pretty interesting theory from somewhere I cant remember, but it goes like this. Theres a section of our brain that acts like a barrier between what we imagine and what is real. This barrier needs rest, so the theory goes, and If it doesnt get rest then it becomes harder and harder to seperate what we imagine and what is real which is consistant with what I have seen happen to people who dont get enough sleep. Weather this holds any validility I dont know, but it sounds good.