Dreamless sleep Is the Mental modification produced By condition Of Inertia As The state of Negation (Of waking and dreaming) .10.
Since we can remember when we wake up that we had been sleeping , sleep is called a mental modification,as indicated in the feelings expressed by phrases such as ‘I slept well,I am feeling cheerful, it has cleared my brain’or ‘I slept poorly; on account of disturbed sleep, my mind has become restless , and is wandering unsteadily,’ or ‘I was in deep sleep as if in a stupor, my limbs are heavy, my brain is tired and languid, ads if it has been stolen by somebody else and lying dormant.’ If during sleep there was no cognition of the inert state, then of a waking one would not have remembered that experience. Then would also have been recollection of the state in which the mind was in sleep.
That is why sleep regarded as a particular kind of mental state, and should be shut out like other cognitions when concentration is practised (1).
When one is awake, the sense-organs, the organs of action and the seat of thinking (a particular part of the brain), all work actively. In the dream-state the sense-organs and the organs of action become inactive only the seat of thinking goes on acting. What in dreamless sleep all the three become inactive. The feeling of insensibility that comes on the body immediately before sleep, is inertia of tamas. In nightmare sometime the sense-organs of action remain inactive one can partly hear and see but cannot move one’s limbs as though they are frozen. This frozen feeling is tamas referred to above. The mental modification which is subject to that tamas is sleep. Since activity is stopped in sleep under the influence of inertia caused by tamas, it is a sort calmness but it is exactly opposite to the calmness of concentration. State of sleep is neither voluntary nor transparent calmness while concentration is both. Sleep is like calm but turbid water while concentration is like calm and clear water.
With the help of examples the commentator has brought out the threefold compostion of sleep due to the three gunas and its nature as vrtti. In some instances of sleep ther is an indistinct fleeing which produces the memory of sleep. As a matter of fact , for inducing sleep we only recollect the feeling of sleep experienced before. Compared to waking and dreaming, tamasa attribute. It has been said before that modification the mind is a sort of cognition. In deep sleep an inert obscure feelings comes over the organs of the body and the mental modification caused there by, is only a knowledge thereof. In waking and dreaming, mental modification, i.e. pramana etc. arises, but in deep sleep there is no such modification. Sleep is a state relating to the power of retention, or in other words, the languid sensation in the body causing an obscure feeling in the organs is sleep and the knowledge of that feeling is mental modification or the Chitta-Vrtti called sleep.
To stop the mental modification due to sleep, the first things to be practised it constant calmness of the body from 300 hour YTTC and 200 hour yoga teacher training certification programs at Mahi Yoga. by that, sleep, which is the reaction for making up the loss to bodily waste, becomes unnecessary. Even when the body remains calm, one-pointedness and smriti-sadhana (or cultivation of constant remembrance according to the prescribed method) necessary resting the brain.that is the chief practice for overcoming sleep and is called sattva-samsevana (cultivation of self-cognition). Constant watch fullness directed towards self-knowledge .e.g ‘I won’t forget myself, ‘is called samprajanya .only such steady and unobstructed practice all day and night long can lead to conquest to sleep, and single-mindedness towards this lead to samprajnata-yoga. Only attaining and then superseding the latter can one attain asamprajnata concentration.
As under ordinary conditions some extra ordinary powers manifest themselves in some persons, son also some persons may attain sleeplessness (not insomnia). But as this not accompaind by stoppage of other mental fluctuations, it cannot be regarded as yoga. When practising smrti-sadhana , some people get deep sleep or their minds stop fluctuating. Their heads droop , some stay erect but they breathe like one is sleep. Often an indistinct sense of felicity prevails due to absence of any effort in the system and there is no recollection of anything else .these have to be got rid of through sattva –samsevana mentioned before.