REM and NREM Sleep Cycle - Know What Happens While You Sleep

REM sleep cycle is an ongoing study in the field of medical science and human psychology. This SleepHearty write-up offers an insight into the cycle of this sleep pattern.
Narayani Karthik
Last Updated: Dec 10, 2017
REM sleep means Rapid Eye Movement sleep. When a person sleeps, he closes his eyes and falls into a trance of a heightened anabolic state. The sleep he enjoys, may or may not contain dreams. However, if this sleeping person encounters elaborate dreams with frequent twitching of hands and feet, and persistent movement of the eyes with a decreased ability to react to a stimulus, the term coined for such a sleep is REM sleep. A normal sleep is divided into two stages of sleep:
- NREM Sleep (Non rapid eye movement sleep)
- REM Sleep (Rapid eye movement sleep)
Sleep Cycles During REM
A normal sleep is divided into different stages consisting of the REM and the NREM sleep cycle. Every stage of a sleep cycle is determined by the amplitude and frequency of the brain waves produced during sleep. A complete sleep cycle is about 90-100 minutes long and a normal sleep comprises 4-5 complete sleep cycles. A sleep cycle has about 5 stages, of which the first 4 sleep cycles cover the NREM sleep stage. The NREM cycles complete once, and quickly reverse again to be followed by the REM cycle. Considering that every sleep cycle is taking 100 minutes to wind, the length is approximately 10 minutes. However, this is not a fixed duration, as the sleep cycle length starts to increase with time when the third and fourth stages of NREM start to wane. The maximum length of a sleep cycle of REM is about an hour, which happens after several rounds of sleep cycles.
Stages of Sleep | Activities | Duration |
Slow wave sleep - NREM Stage 1: Drowsiness |
|
10-15 minutes (approx.) |
Slow wave sleep - NREM Stage 2: Light Sleep |
|
10-15 minutes (approx.) |
Slow wave sleep - NREM Stage 3: Deep Sleep |
|
about 20 minutes (approx.) |
Slow wave sleep - NREM Stage 4: Deep Sleep |
|
About 30 minutes (approx.) |
REM sleep - Stage 5: Dream Sleep |
|
10 minutes to 1 hour |
Sleep is the most wonderful experience cum routine for a person. It is a natural form of meditation with absolute concentration. Deprivation of a regular sleep routine can lead to impaired thought processes, weakened immune system, chronic depression, and sleep disorders like insomnia. The significance of REM sleep cycle is that, it keeps the brain active and enhances the cognitive thought processes of the person by choosing to remember what is required and discard what is not required.