When this is over, the cycle starts over; the original star dies and becomes a white dwarf. White Dwarf The core of a white dwarf star surrounds itself with layers of hydrogen, which still burn, continuing to fuse.
REM sleep is important because it is the restorative part of our sleep cycle. Typically, you begin the sleep cycle with a period of non-REM sleep followed by a very short period of REM sleep. The period of non-REM sleep is made up of stages 1 to 4. Each stage can last from 5 to 15 minutes.
REM Rebound. Since the body needs REM sleep, it has developed a way to recover from sleep deprivation. This process is called REM rebound, which involves shortening the amount of time required to reach REM sleep. Normally, a person requires between 90 and 120 minutes to complete a REM cycle. In the case of REM rebound, people can take much less time to achieve full REM sleep.