Prāṇāyāma

Prāṇāyāma ('extension or restraint of prāṇa') is the fourth limb of Patañjali's yoga, defined in Yoga Sūtra 2.49 as the regulation of the movement of inhalation and exhalation once āsana is established. The Haṭhayoga Pradīpikā describes eight kumbhakas (breath-retentions). This reference describes these practices as they appear in the texts.