So this verse describes in the manner of yogic practice. The yogic practice means controlling five kinds of air within the body: prāṇa, apāna, vyāna, like that. That is breathing exercise, yoga practice.
So it appears that Mahārāja Yudhiṣṭhira knew how to practice the yoga. Not only Mahārāja Yudhiṣṭhira, practically any high-class man, especially the brāhmaṇas and the kṣatriyas, every one of them knew this practice, yoga practice. So at the time of death they could utilize, how to give up this body. That is perfection of yoga. The yogis, they can give up the life or give this, relinquish this body, according to his own desire, not compelled by the material condition. That is yoga system.