Five primary forms
Indian tradition distinguishes five regional modes of prāṇa in the body: prāṇa proper (the upward motion in the chest, governing inhalation), apāna (the downward motion in the abdomen, governing elimination and birth), samāna (the equalising motion at the navel, governing digestion), udāna (the ascending motion in the throat, governing speech and rising consciousness), and vyāna (the diffuse motion through the body, governing circulation). Yogic and ayurvedic interventions are often pitched specifically at one of these.
Cognate concepts
Qi (Chinese), ki (Japanese), pneuma (Greek), ruach (Hebrew, breath/spirit) and mana (Polynesian) are all close cousins of prāṇa. Each tradition has its own technical taxonomy and practical interventions, but the underlying intuition — that something flows in the body and conditions both physiology and consciousness — is unusually consistent across cultures that did not share an origin. Modern medicine treats this as folk psychophysiology; the contemplative traditions treat it as direct observation.
Practice
Prāṇāyāma is the formal yogic discipline of regulating prāṇa through specific breath patterns — extended exhale, alternate-nostril, retention, and so on. The practical claim is that prāṇa and attention are coupled tightly enough that working on the breath directly conditions consciousness. The serious literature is unusually consistent on which practices produce which effects, and modern physiology has begun to confirm the broad outlines via the vagus-nerve and HRV literatures.
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