Prana is the life force — the stuff of those million, zillion stars circling and exploding. Human beings receive it directly into the body through the air. We take it in in other ways as well — through live foods such as fresh fruits and vegetables, through fresh water; through living, breathing trees and vegetation, and, if we're open, through the love of other people and creatures. We probably take it in in more mysterious ways, too, I think — through music, and the sound of inspiring words and perhaps through beautiful sights.

Stephen Cope in Kripalu Yoga by Richard Faulds