Prāṇa accesses both the physical and the mental levels: in the physical plane it appears as breathing, and in the mental as psychic activity.
Through prāṇāyāma, the yogi consciously redirects and channels the life force, allowing it to flow freely through the system of nāḍīs,or “energy conductors”, which are similar to the veins, but in the astral body. During the practice we can watch the powerful flow of this life force within ourselves and attentively expand it, until harmonizing it with the pulsation of the cosmic force.
This method has been presented to the Western public as a group of proper breathing techniques. This definition erroneously directs our attention to a partial and external aspect of prāṇāyāma.
For example, a state of rage causes accelerated breathing, whereas in mental tranquility, the breath is serene, and in a state of great concentration, respiratory activity decreases considerably.
The breathing rhythm varies significantly in different mental and emotional states such as fear, attachment, depression, envy or pride. We sigh upon relief and in moments of suspense we hold the breath; when we face beauty our breathing stops, and the experience of pain causes heavy breathing. Negative mental states can be overcome and replaced by positive ones through techniques of prāṇāyāma that influence the rhythm of breathing.