What is a Sleep?
A healthy sleep is when the nervous system is inactive, eyes are closed, postural muscles relaxed and consciousness nearly suspended. It is known as the Sustained Quiescence State that is accompanied by reduced responsiveness to external stimuli, quick reversibility to the wakeful condition, characteristic EEG (electroencephalogram- electrical activity in the brain) changes in different stages end spontaneous occurrence with endogenous periodicity (Circadian Rhythm].
Know about the Sleep Stage:
While sleeping, we pass through four stages of sleep namely- Non-REM 1 to 3 (Rapid Eye movement) sleep. All these stages begin from stage 1 and ends with REM sleep, and again moves onto to Stage 1.
1. You must be surprised to know that we spend approximately 50% of the total sleep time in Stage 2 and around 10% in REM sleep. While, infants spend more than 50% of their sleep time in REM sleep.
Stage 1- This is a "Light Sleep" stage; where we can easily be awakened. It is possible that people who experience this tend to remember vague visual images. Often people will be also have a sensation of falling, where there will be a sudden startling movement.
Stage 2 - In this stage, there is deceased movement of eyes end brain fluctuations become slow, leading to frequent bursts of sleep.
Stage 3- This stage is characterized by slow brain movement coinciding with faster waves. It is impossible to wake someone in these stages as together they are called as Deep Sleep. The eye movement end muscles activities are NIL usually. If a person is awakened during this sleep, he tends to feel irritated and heavy for few hours. And there could be situations when children can experience bedwetting, and sleep walking.
How much sleep is required?
Dr. Amitaabh Varma, Senior Director – Neurology, Max Super Speciality Hospital, Shalimar Bagh says, Neurologically, it is difficult to determine the number of hours that are required for a healthy sleep. Same people are active with only 3-5 hours of sleep per night, while some need at least 8 hours of sleep or more to perform effectively. Please understand your sleep requirement and take adequate amount of sleep. Do not consider daytime sleep as complimentary of nocturnal sleep deprivation. Afternoon nap only relaxes you physically for prolong sleep deprivation but it will not be useful for complete physiological functions of sleep. Usually average adults would require 7-8 hours of sleep. A Sleep less than 4 hours or more than 9 hours is harmful.
Why we sleep?
Sleeping is not a passive process end as it is associated with several active functions like healing, memory consolidation, and hormonal balance end growth. Internal Repair, end pain, pathway maintenance are some of the other functions of sleep while pain defensive pathway is activated only with good quality of sleep. You must know that sleep is not putting mental and physical activities on hold but a second state where mental and physical activities ere complex.
It has been observed that lack of sleep can cause damage to arteries and lead to heart problems. People who are not getting enough sleep risk getting obese due to decrease Levels of Leptin, a hormone that is a mealtime signal, indicating that your body is full. People who are sleeping less, snoring more, tossing and turning eyeing the clock, praying in dawn- are more fatigued and go to sleep before time. Below mentioned are few disorders caused due to lack of sleep:
- Sleep Walking