The right respiration is called the solar respiration, from its heating nature; while the left respiration is termed the lunar respiration, from its cooling character. The susumna respiration is called the shambhu-nadi. During the intermediate respiration the human mind should be engaged in the contemplation of the supreme soul.
The breath takes its origin from the "indiscreet" or unreflecting form, and the mind from the breath. The organs of sense and action are under the control of the mind. The Yogis restrain their mind by the suspension of breath. Breath is the origin of all speech. The word soham is pronounced by a deep inspiration followed by expiration carried on by the nostrils…. This word means, "God is in us." There is another word called hangsha. This is pronounced by a deep expiration followed by inspiration. Its meaning is "I am in God."
The inspiration is sakti, or strength. The expiration is siva, or death. The internal or Kumbhaka is a promoter of longevity. When the expiration is not followed by inspiration death ensues. A forcible expiration is always the sure and certain sign of approaching dissolution or death. Both these words soham and hanysha cause the waste of the animal economy, as they permit the oxygen of the inspired air to enter the lungs where the pulmonary changes of the blood occur.
According to Lavoissier, an adult Frenchman inhales daily 15,661 grains of oxygen from the atmosphere, at the rate of 10.87 grains nearly per minute.
The word Om is pronounced by the inspiration of air through the mouth and the expiration of the same by the nostrils.
When a man inspires through the mouth and expires through the nostrils, the oxygen of the inspired air does not enter the lungs where the pulmonary changes of the blood take place. The monosyllable Om thus acts as a substitute for the suspension of the breath.
The waste of the body is proportionate to the quantity of oxygen taken into the system by the respiration. The waste of a man who breathes quickly is greater than that of one who breathes slowly. While tranquillity of mind produces slow breathing, and causes the retardation of the bodily waste, the tranquil respiration has a tendency to produce calmness of mind. The Yogis attain to Nirvana by suspending or holding the breath. The Vedantists obtain moksha, or emancipation of the soul, by holding the mind (mental abstraction). Thus Om is the process of separating the soul from the body. It is the product of the gasping breath which precedes the dissolution of our body. The ancient Hindus utilized the gasping breath of the dying man by discovering the syllable Om.
The syllable Om protects man from premature decay and death, preserves him from worldly temptations, and saves him from re-birth. It causes the union of the human soul to the supreme soul. Om has the property of shortening the length of respiration.
Siva is made to say in a work on "Sharodaya" (an excellent treatise on respiration) that the normal length of the expiration is 9 inches. During meals and speaking the length of the expiration becomes 13.5 inches. In ordinary walking the expiration is lengthened to 18 inches. Running lengthens the expiration to 25.5 inches.
In sexual intercourse the extent of respiration becomes 48.75 inches. During sleep the respiration becomes 75 inches long. As sleep causes a great waste of the body and invites disease, premature decay and death, the Yogi tries to abstain from it. He lives upon the following dietary:—rice, 6 ounces troy; milk, 12 ounces troy. He consumes daily: carbon, 156.2 grains; nitrogen, 63.8 grains.