Sleep is important for many different reasons. If you don't get enough sleep, your immunities actually become weakened and you are more susceptible to catching illnesses. Also, the rapid eye movement, known as the R.E.M. cycle, is a very vital part of your sleep cycle. The R.E.M. cycle allows your brain to organize your day's events and make sense of them. Theoretically, if you never reach R.E.M. .