According to yogic theory, breath retention is an important part of yogic sadhana. There is one retention which is known as kevala kumbhaka. This kevala kumbhaka is said to be the aim one has to attain with the practice of pranayama. Most of the yogic literatures, whether it be Patanjali’s Yoga Sutra or pre-Patanjali yogic scriptures, speak of kevala kumbhaka as the final attainment of pranayama.
Prana is associated with breath yet prana is also separate from breath. An example is of Swami Nadabhramananda who was my guru uncle and guru brother of Sri Swamiji. He had mastered kumbhaka. He was the only one in the world who could hold and retain the kumbhaka for one hour. He could hold the breath for one hour whether he held it in or he held it out, it made no difference to him for he had mastered the subject of pranayama. A lot of research was done on him too. A famous research was done at the Meninger Foundation in the United States. In this research the sannyasi was put in an airtight chamber, his whole body covered with wax. All the orifices were plugged, and for one hour he was asked to play tabla in this airtight chamber, without breathing. Up to that point it is acceptable, yet the research further showed that when a microphone was put on different parts of his body, the scientists used to hear a sound vibration like the last part of Om, mmmmmm. If they placed the microphone on the thigh, the sound would be recorded by the tape recorder, on the back the sound would be recorded, on the head the sound would be recorded. Place the microphone on any part of the body and that humming sound would be recorded.
The sannyasi explained that even without breathing, if the pranas are active they take over the physical autonomic functions of the body. That happens only in kevala kumbhaka.
External retention is the most difficultretention to hold. Internal retention you can hold for longer periods but external you cannot hold for long, for the body craves oxygen, the body craves the air intake. In this condition if you are able to hold your breath out, then you are perfecting kevala kumbhaka. Through kevala kumbhaka the pranas begin to be activated. Pranas are not activated in internal or external kumbhaka.
That is training the lungs and breath, however, pranas are activated only when there is kevala kumbhaka, effortless or spontaneous kumbhaka, even of the outer retention.
In the Yoga Sutras (2:50) Patanjali has played a clever game.
He has mentioned three types of pranayama. He calls inhaling one pranayama, exhaling one pranayama and retention one pranayama. Patanjali does not give any practice of asana, pranayama or even pratyahara. He has not given a single practice in the entire book, yet he has given descriptions of many stages of samadhi. We cannot deal with the basic mind and we are going to deal with eight stages of samadhi?
In the pre-Patanjali scriptures of yoga you discover that the aim of pranayama is to reach external retention. Inhalation, exhalation and internal retention train the body. They train and facilitate the absorption of oxygen from the body. However, the movement of prana, the awakening of prana and the utilization of prana happens when kevala kumbhaka has been mastered, and this comes after mastering external retention.
If you can master external retention without pranayama just by holding your breath out during the day, then that will also facilitate the experience of pranayama.
—31 March 2019, Ganga Darshan, Munger