Why Sleeping May Be More Important Than Studying I already knew that you shouldn't study all night, and that if you didn't get enough sleep you could do worse on a test or in class in general. I didn't know that in REM sleep you consolidate more and get rid of useless information to make more room for the useful information. I am curious to explore how long REM sleep is and when approximately it starts and ends so I can make sure I have enough sleep to at least get through that stage of the sleeping cycle. REM sleep meme Source