The term prana is most commonly used to describe the vital force in its totality, but within the context of the five divisions of Pranic energy the term refers to all the ways in which we take in energy. Inhalation is by far the most important vehicle for absorbing prana, but prana is drawn from other energy sources as well. We also absorb energy from food and water, from sense impressions such as the sights, sounds, and smells we gather through the sense organs, and from ideas and impressions communicated to the mind.
According to the yoga tradition this far-reaching system of vital energy contains five major functions, called variously the five pranas, the five Vayus, or the five Prana-Vayus (the term Vayu means “wind, breath, or life-force”). Each function has a distinct role, and each is integrated into the total system of human energy. If we understand the role of each Prana-Vayu, we can grasp how the forces of prana serve the whole person, and see how disturbances among the pranas reduce our quality of life and lead to illness.