Introduction
This is a state of nature which causes encapsulation to the consciousness of a person.
Definition
The definitions given in ancient texts are as follows-
- The mental process of sleep is knowledge devoid of cognition. Sleep is a state of unconsciousness, although consciousness about one's own unconsciousness endures, according to Acharya Vyas.[1]
- The "Mandukya Upanishad" states that "Alma" experiences Nidra, or the state of not having any dreams or desires, and that condition is known as "Susupti."[2]
- Acharya Charak confirmed that a person experiences sleep when their sensory and motor organs become inactive, their mind (as well as their soul) becomes weary, or both, etc.[3]
- Acharya Susruta taught that sleep happens when Tamas covers the Hridaya, the Chetana's seat. Nidra is the state of combination of mind.[4]
- According to Acharya Dalhana, the Susruta commentator states, that Nidra is the state of combination of mind and intellectual in which the person feels happy.[5]
- According to Astanga Sangraha commentary, stated that, the Manovaha Srotas become accumulated with Sleshma and mind is devoid of sense organs because of fatigue, when individual fell asleep.[6]
Materials and Methods
Materials related to Nidra and Sleep physiology have been collected from different journals, Ayurvedic text books, authentic websites (Pub Med etc.), Reputed Magazines, Authentic literatures, Manuscripts, Sanskrit Dictionary etc,
Significance of sleep
The three primary pyramids of life - Ahara, Nidra, and Brahmacharya -are essential to maintaining human health. Three components; Ahara, Nidra, and Brahmacharya, are compared with triangles in Ayurvedic literature and are referred to as the three Upastambh as or Tripods.
The worth of Nidra is established by its inclusion in the three Upastambha.[7] When discussing Nidra, Acharyas explained that sleep determines happiness and sadness, development and wasting, strength & weakness, virility & impotence, & termination.[8]
Physiology of sleep
Sleep happens when the mind is tired. Sleep is caused by cerebral ischaemia. Ayurvedic mental activities are correlated with higher brain centres such as the associated area, pine and post central gyrus, and so on, which are located in the cerebral cortex. Thus, as a result of the decreased cerebral blood flow, the mind becomes quiet, which leads to sleep.[9] Sleep patterns are controlled While awake, the brain's two main nerve cell systems interact to keep the animal in a state of alertness. The upper brain creates acetylcholine, which the animal uses as a neurotransmitter (NT), while the brain's midbrain receives inputs to activate the thalamus. Consequently, it stimulates the prefrontal brain and produces an awake EEG pattern. But while engaging in Random Eye Movement, the cholinergic nerve cells, thalamus & the cortex are in s condition, similar to wakefulness but the brain is in random Eye Movement (REM) sleep. The difference is supplied by three sets of serve cells in the upper part of the brain stem. The nerve cells that contain the neurotransmitter. Two subsets of hypothalamic nerve cells regulate the brain stem cell groups responsible for arousal. Neurotransmitters called inhibitory NT and GABA are present in one subset of nerve cells located in the ventrolateral pre-optic nucleus. The suprachiasmatic nucleus, which regulates the body's circadian rhythm, has a profound impact on the sleep cycle. Clock genes are present in these hypothalamic nerve cells. wherein sleep, hormones, and other physiological processes go through a biochemical cycle that lasts nearly exactly 24 hours.[10]
Functions of sleep
A good night's sleep promotes the Dhatu Samya (balance of body elements), alertness, clear vision, a healthy complexion, and strong digestion. According to Acharya Susurut, people who get enough sleep at the right times won't get sick of any kind, have a cool, collected mind, gain strength and attractive features, have good virility, have a beautiful body, aren't weak or obese, and have long, healthy lives.[11]
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