I heard that when we sleep that is when our 'soul' goes back to replenish itself from the one 'source of all things'. I guess another way to put it would be to say that when you're sleeping you're actually off to visit 'God' that's why you're not conscious or 'alive' during that time.
I've never actually thought of it that way, but that is certainly an interesting point of view worth looking into. I always assumed that our bodies are resting and repairing during that time.
Well, if you don't sleep, ever, you can die from that. It is extremely rare and I think it has been only documented in humans in cases where it was a specific syndrome that causes inability to sleep.
I think that the body doesn't really need to be asleep in order to rest or repair itself. I believe that the purpose of sleep is to replenish our mental energies. Of course I could be wrong, but I've found that in my life, the more in tune with myself I am (happy, passionate about something, eager to get on with my day every morning, and so on) the less sleep I need. Some nights I only go for 3 hours and yet the next day I'm as fresh as a daisy, ready to go again!
It's amazing that almost everyone has their own viewpoint when it comes to why sleep is necessary for us, but I think that the answer lies in all the different views expressed here.
I think it all depends on what you believe, which means that if you believe that you need 8 hours of sleep a day, but try to get by on 3, then you will undoubtedly have a problem. But if you are sure that you only need a couple of hours of sleep each night, then that is enough for you!
I think sleep is needed to keep the organism functioning efficiently and alive. Sleep-deprived people have disruptions in their biological processes. Lack of sleep is worse than stress for creating such disruptions.