With the modern life-style, an average educated person working almost entirely with his brain is scarcely aware of his own body. He is, no doubt, quite familiar with the stresses he is forced to face, and the resulting fatigue as well as the mental tension. But his knowledge about its process is meagre. Even when one does experience tension, he is unable to pin point exactly where the tension lies. Indeed he has not an inking that his body possesses an innate protective mechanism which, when triggered, can counteract the effects of the overstress. If, therefore, one desires to improve his physical and mental health, he has to re-establish contact with his body.
The process of sarira-preksa is centripetal, i.e. from outside to inside, thus reversing one's usual direction of the flow of consciousness which is from inside to outside. Commencing with the outermost layers of consciousness, one has to penetrate more and more deeply.
The sarira-preksa changes one's perception so that the sensation-signals of pain are experienced without suffering. Same is the case with the signals of the sensation of pleasure.
As stated above, the Sarira-preksa is a centripetal process. Now, the extension of the psyche is on par with that of the body and the spiritual self is on par with the psyche, each and every one of the billions of cells which constitute the body is permeated by the spiritual self, and that is why each cell is sensitive and capable of carrying out metabolic function through bio-chemical and bio-electrical action. In other words, in short, a totally impartial perception of the mass of sensations within the body is 'direct perception' of the psyche and the spiritual self.
It is obvious that sarira-preksa is the only means of complete body-awareness, which, as explained above, is really self-awareness. On the physical level, it helps each cell to revitalize itself; it helps digestion, improves quality and circulation of blood and increases the efficiency of the nervous system and bioelectric activities. On mental level, it is a methodology for training the mind to concentrate on internal phenomena instead of wandering about externally. On the spiritual level, impartial perception of ever-changing biological functions of the body is a means of experiencing the substratum of consciousness through its modes and attributes.