U start dreaming..... Enter rem state
First you are drowsy, then you go into a light sleep where it is easy to wake up, I think this lasts about 10 minutes. Next you begin a proper, deeper sleep, lastly you enter R.E.M. stage, in which you dream. R.E.M. stands for Rapid Eye Movement, which causes you to dream. Pardon me for any errors. U.V. light will help you wake up.
The cells are alive and metabolically active.
It happens in the 4th stage
There are five stages of sleep. Stage 1 being the one you first enter, then followed by stage 2, 3 and 4. As you descend into deeper sleep your brain frequency slows down. In stage 4 can it be slower than one cycle per second (delta sleep). After some time spent in stage 4, about 25 minutes, you return to stage 3 and 2, then straight into REM sleep. About 90 minutes has passed now since you started sleeping. 5-10 minutes is spent in this stage before you go all the way down to stage 4 again (also called non-REM sleep). When approximately 90 minutes have again passed, another REM-period start. This time the REM sleep lasts longer. And as time progresses less time in non-REM sleep is needed and more time is spent in REM sleep. After 4-5 hours you don't go lower than stage 2. Vivid dreaming takes place in REM sleep, so the more you sleep, the more time is spent in REM.
REM or Rapid Eye Movement. You sleep in cycles, moving from lighter to deeper sleep and back. A sleep cycle lasts about 90 minutes, with REM occurring toward the end of each cycle. The REM stage gets a little longer in each cycle; you may only dream for a few seconds in the first sleep cycle, and for a large percentage of the last cycle of the night.
It is a sleep study which shows patterns other than those associated with normal sleep stages architecture. The lighter sleep stage is stage 2, and the deeper stages are 3 and 4, followed by a brief period of REM sleep, before the sleep cycle repeats itself. A healthy night's sleep typically includes five 90 minute sleep cycles. A common abnormal sleep study is one which is associated with multiple apneic episodes, pointing to sleep apnea as a problem (which limits the body's ability to attain the deeper stages of sleep, hence the fatigue and sleepiness the next day despite the subjective perception that one has slept for eight hours or more).
The stage of sleep called REM, for "rapid eye movement", is the stage during which dreams occur. If you are awakened while in REM sleep, you remember your dream. This is one of the deeper stages of sleep, and is named after the fact that an observer can see the subject's eyeballs moving rapidly about beneath closed eyelids during this state.
The deepest stage of sleep is REM or Rapid Eye Movement.
There is alpha or stage one sleep, theta or stage two sleep, delta or statge 3 sleep, and alpha with REM (stage 4 sleep).
You return to stage 3, then stage 2 (delta sleep) before going to REM sleep (stage 5).
You return to stage 3, then stage 2 (delta sleep) before going to REM sleep (stage 5).
You return to stage 3, then stage 2 (delta sleep) before going to REM sleep (stage 5).