A typical night you are lying awake in bed with eyes open, awake but relaxed. Your beta brain waves indicate wakefulness. Growing sleepier, you shut your eyes. Your brain activity slows down to alpha waves. You’re more relaxed, yet still wakeful.
Your nightly cycle
After one’s first REM period, one will fall again into Stages Two, Three and Four, then move back again through Stages Three and Two and into more REM sleep.
This cycle repeats itself every 90 to 110 minutes until you wake up. Depending on the length of time you sleep, you will travel through four or five of these cycles before morning. Remember, dreaming is not the only function of REM sleep. REM sleep is absolutely essential for preparing the mind for peak daytime performance.
Whenever you have a short night of sleep you are eliminating the long REM periods that come towards morning. This can impair your daytime learning, thinking, memory and performance. REM sleep prepares your mind and body for success.