In the classical understanding of Pranayama from the Patanjali Yoga Sutras, it is taught that Prana is the Life Force while Yama is the practice to control. Therefore, Pranayama can be understood as ‘to control the life force’. The various techniques of breath excercises and regulatory methods performed by the Yogi can allow access to deep levels of healing, psychic expansions and vital energy which can both support the overall yogic practice (sadhana) as well as health and strength of the practitioner.
During the practice of Pranayama the stimulation of the system of Nadis in the body are activated, in time giving through experience perception realms beyond the physical such as, the emotional, the pain, the pranic and the bliss bodies. Eventually this leads the practitioners into a process both of self healingand spiritual advancement.
Several interpretations and understandings of what Pranayama is and does has been stated by advanced and realized Yogis as well as has been written in sacred texts of India. Some prominent examples of this come from the well known spiritual teacher Shankaracharya who expressed in his profound teachings on spiritual thought that the practice of pranayama is to retain nothing but the experience, thought and perception of Brahman (pure consciousness).
While in the sacred scripture The Gita, it has been written that there are two aspects to the breath which are; the outgoing (apana) and the incoming (prana). In this manner when these two parts merge together there is the experience of pure Brahman (pure consciousness). In this state of Brahman, it is beyond the mind, the ego, and duality.
In deeper states of Pranayama practice we have purified the mind, body and the nadis to such a degree that true meditation is accessed.