अपाने जुह्वति प्राणं प्राणेऽपानं तथापरे |
प्राणापानगती रुद्ध्वा प्राणायामपरायणा: || 29||
अपरे नियताहारा: प्राणान्प्राणेषु जुह्वति |
सर्वेऽप्येते यज्ञविदो यज्ञक्षपितकल्मषा: || 30||
apāne juhvati prāṇaṁ prāṇe ’pānaṁ tathāpare
prāṇāpāna-gatī ruddhvā prāṇāyāma-parāyaṇāḥ
apare niyatāhārāḥ prāṇān prāṇeṣhu juhvati
sarve ’pyete yajña-vido yajña-kṣhapita-kalmaṣhāḥ
apane juhvati pranam prane ’panam tathapare
pranapana-gati ruddhva pranayama-parayanah
apare niyataharah pranan praneshu juhvati
sarve ’pyete yajna-vido yajna-kshapita-kalmashah
BG 4.29-30: Still others offer as sacrifice the outgoing breath in the incoming breath, while some offer the incoming breath into the outgoing breath. Some arduously practice prāṇāyām and restrain the incoming and outgoing breaths, purely absorbed in the regulation of the life-energy. Yet others curtail their food intake and offer the breath into the life-energy as sacrifice. All these knowers of sacrifice are cleansed of their impurities as a result of such performances.
Some persons are drawn to the practice of prāṇāyām, which is loosely translated as “control of breath.” This involves:
Pūrak—the process of drawing the breath into the lungs.
Rechak—the process of emptying the lungs of breath.
Antar kumbhak—holding the breath in the lungs after inhalation. The outgoing breath gets suspended in the incoming breath during the period of suspension.
Bāhya kumbhak—keeping the lungs empty after exhalation. The incoming breath gets suspended in the outgoing breath during the period of suspension.
Both the kumbhaks are advanced techniques and should only be practiced under the supervision of qualified teachers, else they can cause harm. Yogis who are inclined toward the practice of prāṇāyām utilize the process of breath control to help tame the senses and bring the mind into focus. Then they offer the controlled mind in the spirit of yajña to the Supreme Lord.
Prāṇ is not exactly breath; it is a subtle life force energy that pervades the breath and varieties of animate and inanimate objects. The Vedic scriptures describe five kinds of prāṇas in the body—prāṇ, apān, vyān, samān, udān—that help regulate various physiological bodily functions. Amongst these, samān is responsible for the bodily function of digestion. Some people may also be inclined toward fasting. They curtail their eating with the knowledge that diet impacts character and behavior. Such fasting has been employed as a spiritual technique in India since ancient times and also considered here a form of yajña. When the diet is curtailed, the senses become weak and the samān, which is responsible for digestion, is made to neutralize itself. This is the nature of the sacrifice that some people perform.
People perform these various kinds of austerities for the purpose of purification. It is desire for gratification of the senses and the mind which leads to the heart becoming impure. The aim of all these austerities is to curtail the natural propensity of the senses and mind to seek pleasure in material objects. When these austerities are performed as a sacrifice to the Supreme, they result in the purification of the heart (as mentioned before, the word “heart” is often used to refer to the internal machinery of the mind and intellect).