BG 4.29

4.29 अपाने in the outgoing breath? जुह्वति sacrifice? प्राणम् incoming breath? प्राणे in the incoming breath? अपानम् outgoing breath? तथा thus? अपरे others? प्राणापानगती courses of the outgoing and incoming breaths? रुद्ध्वा restraining? प्राणायामपरायणाः solely absorbed in the restraint of breath.Commentary Some Yogis practise Puraka (inhalation)? some Yogis practise Rechaka (exhalation)?,and some Yogis practise Kumbhaka (retention of breath).The five subPranas and the other Pranas are merged in the chief Prana (MukhyaPrana) by the practice of Pranayama. When the Prana is controlled? the mind also stops its wanderings and becomes steady the senses are also thinned out and merged in the Prana. It is through the vibration of Prana that the activities of the mind and the senses are kept up. If the Prana is controlled? the mind? the intellect and the senses cease to function.

— vedicscriptures · exposition · source ↗

This system of yoga for controlling the breathing process is called prāṇāyāma, and in the beginning it is practiced in the haṭha-yoga system through different sitting postures. All of these processes are recommended for controlling the senses and for advancement in spiritual realization. This practice involves controlling the airs within the body so as to reverse the directions of their passage. The apāna air goes downward, and the prāṇa air goes up. The prāṇāyāma-yogī practices breathing the opposite way until the currents are neutralized into pūraka, equilibrium. Offering the exhaled breath into the inhaled breath is called recaka. When both air currents are completely stopped, one is said to be in kumbhaka-yoga. By practice of kumbhaka-yoga, one can increase the duration of life for perfection in spiritual realization. The intelligent yogī is interested in attaining perfection in one life, without waiting for the next. For by practicing kumbhaka-yoga, the yogīs increase the duration of life by many, many years. A Kṛṣṇa conscious person, however, being always situated in the transcendental loving service of the Lord, automatically becomes the controller of the senses. His senses, being always engaged in the service of Kṛṣṇa, have no chance of becoming otherwise engaged. So at the end of life, he is naturally transferred to the transcendental plane of Lord Kṛṣṇa; consequently he makes no attempt to increase his longevity. He is at once raised to the platform of liberation, as stated in Bhagavad-gītā (14.26) : māṁ ca yo ’vyabhicāreṇa bhakti-yogena sevate sa guṇān samatītyaitān brahma-bhūyāya kalpate “One who engages in unalloyed devotional service to the Lord transcends the modes of material nature and is immediately elevated to the spiritual platform.” A Kṛṣṇa conscious person begins from the transcendental stage, and he is constantly in that consciousness. Therefore, there is no falling down, and ultimately he enters into the abode of the Lord without delay. The practice of reduced eating is automatically done when one eats only kṛṣṇa-prasādam, or food which is offered first to the Lord. Reducing the eating process is very helpful in the matter of sense control. And without sense control there is no possibility of getting out of the material entanglement.

— vedicscriptures · exposition · source ↗