Sleep is vital for the body since it is the only time that our mind and body both are at rest. The body carries out all the repair works from the wear and tear it faces during the day in the night while sleeping. It is therefore vital to rest and sleep, even though modern lifestyles keep us awake for long periods of time, late into the night. Also, for many, the working hours are now erratic, with nighttime work schedules, which disrupt the body clock and have repercussions on the body.
To understand why sleep is so important, it is first necessary to learn about sleep and its phases.
Sleep and its phases
Sleep has a lot of health benefits, but those are only felt if the body rests peacefully and it reaches the deep phase of sleep.
The phases of sleep are categorized as-
- Non-Rapid Eye Movement or NREM
- Rapid Eye Movement or REM
These two phases repeat each other in a cyclic pattern after every 90 minutes. Approximately, 75 percent of the sleep is NREM where it progresses from light sleep where one can easily be awakened to slightly deep sleep and further deep sleep where the body is completely relaxed and fast asleep. Replenishing of energy and hormones, increase in oxygen supply and blood supply to the muscles and repair of the body takes place in this third stage of NREM.
Post this stage the sleep becomes little lighter where rapid eye movement is observed, termed as REM sleep. In this stage, the brain is completely active, heart rate goes up, blood pressure and body temperature increases and the body experience most dreams at this stage.
Importance of the sleep phases
NREM sleep allows bodily repair and relaxation to take place.
REM sleep is, however, equally vital as it affects the brain functioning and the ability to learn, moods and retain memory. Sleep deprivation leads to fewer hours of REM sleep thus causing issues with learning and retaining memory of what is taught or what you did. The central nervous system gets affected by lower REM sleep.
Ideally, adults need 2 hours of REM sleep, the duration of which lessens with age. The combination of deep sleep stage of NREM and REM sleep is absolutely necessary for the body to function well and stay fit else it experiences problems, such as blood pressure, diabetes, heart disease, stroke, kidney failure as well as affecting the memory and learning skills.
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