Sri Paramahansa Yogananda, C 27, Autobiography of a Yogi.

 Realizing that man's body is like an electric battery, I reasoned that it could be recharged with energy through the direct agency of the human will. As no action of any kind is possible without willing, man may avail himself of the prime mover, will, to renew his strength without burdensome apparatus or mechanical exercises. By the simple Yogoda techniques, one may consciously and instantly recharge his life force ( centered in the medulla oblongata ) from the unlimited supply of cosmic energy.