Prana (प्राण, IAST: prāṇa) is a Sanskrit wor that refers to a vital, life-sustaining force of living beings and vital energy in natural processes of the universe. Prana is a central concept in Ayurveda and Yoga where it is believed to flow through a network of fine subtle channels called nadis. The three main channels are: the ida, the pingala, and the sushumna. Ida relates to the left side of the body terminating at the left nostril and pingala to the right side of the body terminating at the right nostril. In some practices, alternate nostril breathing balances the prana that flows within the body. When prana enters a period of uplifted, intensified activity, the Yogic tradition refers to it as Pranotthana.