In Ayurveda, the nidra (sleep) has been said to be due to Ratriswabhava Prabhava. Acharya Charaka has rightly told that the sleep caused by the nature of the night is the sleep par excellence and is called as Bhutadhatri and it nurses all the living beings.
The evolution took place when the Srusti Karta Brahma was in awakened state, and the destruction or pralaya, when he was asleep. Hence sleep of Brahma was a destructive state for living beings. But for the living beings in the world including plants, the sleep is an essential phenomenon like food and water and also it restores the energy like them.
From the Vedic and Upanishad period it self, the yogis studied about the yogic phenomenon pertaining to various stages associated with Atma. They have termed these stages as 1. Jagratavastha (Waking phase), 2. Swapnavasta (Dream phase), 3. Susuptavasta (Sleep phase) and 4. Samadhi avastha (the conscious sleep phase), having detachment from the eternal world in different degrees.
In Patanjali yogasutra the physiology and importance of nidra was described as : A state of deliberate absence of thought waves or knowledge. Dreamless sleep is an inert state of consciousness in which the sense of existence is not felt. In sleep, the senses of perception rest in the mind, the mind in the consciousness and the consciousness in the being in deep sleep. The senses of perception cease of function because their supreme, the mind is at rest. This a Abhava, a state of void or a feeling of emptiness.
Lord Krishna has explained the importance of proper sleep for adhyana yogi in Bhagavatgeeta. He also mentions to Arjuna that the excessive sleep or awaking is not good.
meaning of Word NIDRA
The prefix “Ni” is the Sanskrit root of our English word “Nether” or down as in “nether world” (under world).
While the suffix “dra” may be cognate with the English “drowsy”, to be half asleep, to be inactive or present an appearance of peaceful inactivity or isolation.
The word nidra is a feminine gender, the root “dra” means undesired and “gatau” to lead; it is a state which is hated, there for turned as “Nidra”.
The different interpretations about the phenomenon of nidra may be classified under four groups.
- Upanishad Concept.
- Ayurvedic Concept.
- Yogic Concept. Upanishad Concept
The ancient theories discussed here are based on the available Indian literature and Ayurvedic literature at present. The discussion about the sleep is one of the important topics of the Upanishad.
a. The fatigue theory of sleep is just in the pattern of the modern physiology; concept of sleep has been explained with an example of a bird. A Falcon or any other bird. A falcon or any other bird after having flown in the sky when gets tired returns in the nest by folding wings.
b. According to some others, sleep is caused by the sense of being absorbed in the highest sensation or the mind, just similar as the rays of sun become collected in the bright disc at the time of sunset. So do all senses become collected in the mind. This is the reason why man is not able to hear, to see or to smell in deep sleep.
c. This statement can be further exemplified according the reason of sleep is that the mind is merged into the ocean of light, when he is overpowered by light, then does the soul see no dreams and at that time great happiness arises in the body.
d. Another theory says that sleep is caused by the soul getting lodgment in the arteries. When a man is fast asleep, being happy, come across no dreams as the soul has moved in the arteries during that state.
e. The sleep is found to be explained in other ways also. According to the sages, the sleep occurs in the mind is merged in prana.
f. Nidra occurs when the soul goes to rest in the space inside the heart (Brihadaranyaka Upanishad).
More elaborate description regarding the sleep, its role in the maintenance of health is found in Ayurvedic classics and the later literature of Upanishads, Charaka and Vagbhata have considered the nidra as one of the Upasthambha.
Acharya Kashyapa also highlighted the importance of nidra as; the timely implemented sleep is an indicator of good health as it brings the normalcy in body tissues and relaxes the person.
Yogaratnakara says that a person who is enjoying sleep does not easily become a victim of diseases. His life will be with health, vigor and longevity.
Sushruta states that if one remains in a locality that is contributed to the aggravated dosha, the person need not fear, provided his diet, sleep and regimen are of such nature as are necessary for the pacification of doshas concerned.
As such in Ayurveda the nidra has been said to be due to Ratnswabhava Prabhava. Acharya Charaka has rightly told that the sleep caused by the nature of the night is the sleep par excellence and is called as Bhutadhatri and it nurses all the living beings. Though the role and importance of sleep are very widely accepted, if the sleep is not appropriately implemented in quantum and time, it may have adverse effects on the body.
Four theories for explaining mechanism of sleep
- Tamoguna Theory.
- Kapha Dosha Theory.
- Depression Theory
- Svabhava Theory Tamoguna Theory
This is the darshanika theory of sleep. In darshanas, Tamas has been held responsible for ignorance, less of consciousness, inattention and sleep. The theory concept that, at night since the Tamas being powerful, the higher psychic centers gets overpowered by it and sleep manifests. The Hridaya is the seat of consciousness when that is covered by Tamas, the person goes to sleep. Tamas is hence cause for sleep and the satva for consciousness.
Kapha Dosha Theory
This is the ancient medical theory of sleep, in fact it is a modification of the Tamoguna Theory. Kapha is supposed to be composed mostly of Tamas. Therefore, the increased kapha has been related with more or less the qualities of kapha.
According to this, whenever chetna is overpowered by the accumulation of Tamas, the sensory channels of the body gets blocked or checked by the Kapha. When this shleshma is oversaturated with tamasika qualities then the living being gets sleep.
Charaka propagated this theory, when mind and the organs of sense become so tired that they cannot be stimulated to activity, the person goes to sleep.
Due to natural process or due to exhaustion etc. when the mind becomes inactive along with sensory and motor organs then the person goes to sleep.
Even after the description of role of Tamas in sleep Sushruta told that it is the natural instinct, which forms the most powerful cause for sleep. So, he also counted it as svabhavika by nature and the, night serves as causative factor for sleep (Ch.Su. 21/ 58).
There are four natural instincts for the human beings like
- Desire to take the food.
- Desire to take the water.
- Desire to have sleep.
- Desire for sexual pleasure.
Sleep According to Astanga Hridayakara – Four Types.
- Akale sevitha – Mithyayaogaroopa -taken in wrong manner.
- Atiprasghath sevitha – Atiyogaroopa – excessively taken.
- Na cha sevitha – heenayogaroopa – nadequate sleep
- Nishevatha – Niyathativenitha setitha – properly taken
According to Sushruta – Three Types
- Vaikariki Yogic Theory
The yogic philosophers of India also gave explanation regarding sleep and also explained the Samadhi state which resembles the sleep but entirely opposite to that.
Bhagavan Sn Krishna while discussing Dhyana yoga or yoga of meditation said that the yogi should be regulated in sleep and wakefulness, and he also told that, the sleeping (swapna), smelling etc, are the functions of five organs and breathing points to function of five vital airs and the sleeping denotes the function of inner sense or mind.
Patanjali mentioned sleep as a state in which all activities of thought and feeling comes to an end. In sleep the senses of perception rest in the mind. In deep sleep, the senses of perception cease to function because the mind is at rest. After awakening, the consciousness or mind will be aware about its consciousness.
Yoga Nidra – A Yogic sleep process
The Indian philosophy teaches the existence of four levels of consciousness as
- 1. Waking consciousness (Jagrutavasta)
- 2. Dreaming consciousness (swapna)
- 3. Dreamless sleep (Sushuptha)
- 4. Conscious dreamless sleep (turiya)
Nidra and Prakriti
According to the individual’s prakriti and vayo-avastha the sleep requirement vanes. The sleep according to prakriti may be divided into two types.
a. The sleep according to Deha prakriti.
b. The sleep according to Manasa prakriti.
Sleep is produced by tamoguna and slesma, hence the quality of sleep varies according to the prakriti of the person. So an individual of kapha prakriti gets more sleep which is sound also. Similarly, the sleep also depends on age; in balyavasta kapha is predominant so sleep is comparatively more in this age than the yuvavastha. In vrudhavastha vata is predominant so the old aged gets very less sleep. Apart from deha prakriti some naturally gets less sleep.
Sleep according to Manasa prakriti
Mind is always flickering and it is governed by the pranavayu. The Tamas and Rajas principally maintain mood of a person. Hence the person of the tamasika type can sleep at any hour of the day. Those with rajasika type of person sleep either daytime or night time and their sleep is light and disturbed.
Nidra and Kala
Manu, the great lawmaker has described the division of time, and then has remarked that the thirty muhurtha period (24 hrs) is divided by sun into day and night, he described that day for activities and the night for rest.
Naturally, the night is described as a proper sleeping time. The person should not awake at night and should not sleep in day time because both cause dosha prakopa.
Shayya and Nidra
Sleeping on a cot is tndosha shamaka and is a promoter of good health. Sleeping on a bed on the ground neutralizes vata and kapha, sleeping on the ground results in obesity, increases virility, increases vata and dryness in the body and neutralizes rakta pitta. Sleeping on a plank of wood increases vata. Sleeping on a comfortable bed in general increases happiness, sexual desire and virility and helps in getting rid of excess of vata and exhaustion.
After taking the dinner when a person goes to sleep first he should lie down in recumbent posture taking 8 times breath. He should change the posture to right lateral till taking 16 times breath and there after to left lateral till taking 32 times breath and then he can sleep at any posture according to his wish (Y.R. 192).
But it is always advised to sleep in the left lateral position because agni lies in the left side of the body above the nabhi, which is responsible for the proper digestion (Y.R. 193).
Relationship between Nidra and Dosha dhatu malas
As nidra is said to be kapha dominant process it also maintains the equilibrium between three doshas. In classics, it is mentioned that in kaphaja vikaras nidra and tandra are commonly seen and in vataja vikaras nidranasa (Loss of sleep) occurs and in pittaja vikaras alpanidra (Less sleep) manifest. By means of proper sleep the dhatusamya, nourishment of the body, increase of strength and the stability of Ayu are achieved.
By proper sleep the digestive power is properly maintained and the agni functions remains in normal condition. Evacuation of the bowel and emptying of urinary bladder take place properly if a person sleeps well.
Bad habits like ratri-jagarana (waking up during night) and diva-swapana (sleeping in the day) have been stated to provoke all the three doshas.
Karmukata of Nidra at different Dhatu Level.
- Rasa Pusti and varnaprada
- Rakta Varna, agni deepti
- Manisa Pusti and Bala
- Meda Attractiveness
- Asthi Bala
- Majja Vrana, Utsha
- Sukra Utsaha Ojus Jivnana Manas Sukha , Gnana Conclusion
Ancient description of Ayruveda and Yoga have given importance to sleep and described different patterns of sleep with their significance in the maintenance of positive health.
It has been observed that all the living beings enjoy sleep to keep their body and mind energetic.
Research news articles about sleep :
Lack of sleep ‘linked to early death’
Getting less than six hours sleep a night can lead to an early grave, UK and Italian researchers have warned.
They said people regularly having such little sleep were 12% more likely to die over a 25-year period than those who got an “ideal” six to eight hours.
They also found an association between sleeping for more than nine hours and early death, although that much sleep may merely be a marker of ill health.
Sleep journal reports the findings, based on 1.5m people in 16 studies.
(Read more about this at : http://news.bbc.co.uk/2/hi/health/8660373.stm )