BG 4.29
प्राणापानगती रुद्ध्वा प्राणायामपरायणाः ॥
prāṇāpāna-gatī ruddhvā prāṇāyāma-parāyaṇāḥ
Word-for-word meanings
apare — others; parāyaṇāḥ — who are devoted; prāṇāyāma — [to] the regulation of the vital force; ruddhvā — while restraining; gatī — the movement; prāṇa — [of] the ascending vital current; apāna — [and of] the descending vital current; juhvati — offer; prāṇam — the ascending vital current; apāne — into the descending vital force; tathā — and; apānam — the descending vital current; prāṇe — into the ascending vital force.
Translation
Others, who are devoted to the regulation of the vital force (prāṇāyama*), while restraining the movements of the ascending and descending vital currents, offer the ascending current into the descending force and the descending current into the ascending force.
Notes
* Prāṇāyāma means the regulation or expansion of the vital force (prāṇa) in the body. This is accomplished by regulation of the breath, which is the prime carrier of the vital force. The one indivisible prāṇa functions in five capacities within the body, and hence it is understood to be of five types, namely, prāṇa, apāna, samāna, udāna, and vyāna.