Excerpts-Lessons by Swami Paramahamasa Sivananda of Divine Life Society Hrikesh
Stage 1: Basic Lessons-Practical Lessons in Yoga
Prana means breath and Ayama means control. By Pranayama is meant the control of Prana and the vital forces of the body.
Pranayama begins with the regulation of breath and ends in establishing full and perfect control over the life-currents or inner vital forces. In other words, Pranayama is the perfect control of the life-currents through regulation of breath.
Breath like electricity is gross Prana. By establishing control over the gross Prana, you can easily gain control over the subtle Prana inside.
The process by which such control is established is called Pranayama. Pranayama is the fourth limb of Ashtanga Yoga.
Prana is the oldest for, it starts functioning from the very moment the child is conceived. On the contrary, the organs of the body such as hearing, and so forth, begin to function only when their special abodes viz., the ears, etc., are formed.