Bhagavad Gita Chapter 4 Verse 29
भगवद् गीता अध्याय 4 श्लोक 29

अपाने जुह्वति प्राण प्राणेऽपानं तथाऽपरे।
प्राणापानगती रुद्ध्वा प्राणायामपरायणाः।।4.29।।



English Translation - Swami Sivananda
4.29 Others offer as sacrifice the outgoing breath in the incoming, and the incoming in the outgoing, restraining the course of the outgoing and the incoming breaths, solely absorbed in the restraint of the breath.


English Translation of Sanskrit Commentary By Sri Shankaracharya's
4.29 Pranayama-parayanah, constantly practising control of the vital forces-i.e. they practise a form of pranayama called Kumbhaka (stopping the breath either inside or outside) [Three sorts of motion of Pranayama (control of the vital forces) are, one by which we draw the breath in, another by which we throw it out, and the third action is when the breath is held in the lungs or stopped from entering the lungs.-C.W., Vol.I, 1962, p. 267. 
Thus, there are two kinds of Kumbhaka-internal and external.]-; prana-apana-gati ruddhva, by stopping the movements of the outgoing and the incoming breaths-the outgoing of breath (exhalation) through the mouth and the nostrils is the movement of the Prana; as opposed to that, the movement of Apana is the going down (of breath) (inhalation); these constitute the prana-apana-gati, movements of Prana and Apana; by stopping these; some juhvati, offer as a sacrifice; pranam, the outgoing breath, which is the function of Prana; apane, in the incoming breath, which is the function of Apana-i.e. they practised a form of pranayama called Puraka (filling in); while tatha apare, still others; offer apanam, the incoming breath; prane, in the outgoing breath, i.e. they practise a form of pranayama called Recaka (emptying out). [Constantly practising control of the vital, forces, they perform Kumbhaka after Recaka and Puraka.]


Transliteration Bhagavad Gita 4.29Apaane juhwati praanam praane’paanam tathaa’pare;
Praanaapaana gatee ruddhwaa praanaayaamaparaayanaah.


Word Meanings Bhagavad Gita 4.29apāne—the incoming breath; juhvati—offer; prāṇam—the outgoing breath; prāṇe—in the outgoing breath; apānam—incoming breath; tathā—also; apare—others; prāṇa—of the outgoing breath; apāna—and the incoming breath; gatī—movement; ruddhvā—blocking; prāṇa-āyāma—control of breath; parāyaṇāḥ—wholly devoted; apare—others; niyata—having controlled; āhārāḥ—food intake; prāṇān—life-breaths; prāṇeṣhu—life-energy; juhvati—sacrifice; sarve—all; api—also; ete—these; yajña-vidaḥ—knowers of sacrifices; yajña-kṣhapita—being cleansed by performances of sacrifices; kalmaṣhāḥ—of impurities