Prana

The Sanskrit prāṇa joins the prefix pra-, "forth," with the root an, "to breathe" — literally "breathing forth" or "that which moves forward continually." In its earliest usage it names the breath itself, yet the word soon widened to mean the vital force believed to animate every living thing.

Beyond breath, prāṇa is understood as the animating energy pervading body and cosmos alike. Classical yoga subdivides it into five vāyus, or "winds" — prāṇa, apāna, samāna, udāna and vyāna — each governing a region and function, from intake and downward elimination to assimilation, upward movement and circulation throughout the whole.

The Haṭha Yoga Pradīpikā and Gheraṇḍa Saṃhitā treat prāṇa as the very material yoga works upon, taming it through prāṇāyāma so the restless mind grows still. The Praśna Upaniṣad devotes an early inquiry to prāṇa and its distribution. Where a verse number is uncertain, none is offered here rather than guessed.

In practice you meet prāṇa through the breath. Slow, even breathing, gentle retention and the bandhas are said to gather and steer it along the subtle channels. Many practitioners simply notice how sustained attention to the breath shifts mood, steadiness and energy — a felt, first-person acquaintance rather than any measurement.

Prāṇa belongs to a contemplative and traditional model of the body, not to physiology; it is not oxygen, nerve signal, or any measurable substance, and claims otherwise misread it. Treat the descriptions of vāyus and channels as an experiential map that supports practice, not as a statement of anatomical or medical fact.