Sleep

Sleep sometimes seems like a big waste of time. Just think about how many things you could do instead of sleeping. Why do we need sleep at all? I think we all have considered about these things. And I also got interested so I started searching for some information.
Sometimes i feel great even if I sleep only 6hours, but sometimes I sleep 10hours and when I awake I still feel tired. It is known that nowadays one needs about 8hours of sleep to feel totally rest. What is more if we wake up at REM faze we feel more relaxed weather on other fazes.
And another interesting thing I find out, would be a great advise for all of you. If you are having an exam and only one night is left for learning you should remember that sleep, especially REM sleep, is very important for memory and learning. But if there is no possibility to learn earlier you should try counting the time and leave the exact time for all 4states of sleep. That you would awake at REM faze.
So as you see sleep is very important for our lives and it is also useful to find out more about sleep, to live a full value life.