Breathing forms the most vital process of life-activity. This action keeps up till the time of death and, in the meantime, the blood is being purified and aerated through the lungs. All the organs of the body work in rhythm as long as they are kept supplied with pure blood from the heart. Moreover, few people know, and fewer still care to know that every change in the mental state is accompanied by a corresponding change in the volume, force and rhythm of respiration. Likewise, the yogis maintain that the rise and fall in the depth of respiration cause a corresponding change in the activity of the brain; and that such a continual interaction between the brain and the lung can be safely utilized for supra-physical and supra-mental achievements.

The best means for creating harmony and concentration within, therefore, is first to create harmony in breathing, and this could only be very effectively done through the various Yoga breathing methods. Therefore, Yoga takes aid of breathing essentially with a view to controlling the functions of bio-energy (prāna), and through such control, to gaining mastery over the mind. However, according to Yoga, the respiratory movements represent only a portion of the grosser activities of the life force (prāna).