Prana is the vital air, or breath, of the human body, as visualized in Hinduism. Also interpreted as the vital, life-sustaining force of both the individual body and the universe. Its first expounding came in the Upanishads, where it is part of the worldly, physical realm, sustaining the body and reliant on the mind. Prana suffuses all living form but is not itself the Atma or individual soul.

In practical terms, prana can be explained in various ways. Feelings of hunger, thirst, hot, cold, etc. in the body are pranic manifestations. All physical feelings or energies that arise or flow within the body are evidence that prana is at work. Prana is the life force, or vital energy. The presence of prana is what distinguishes a living body from a dead one. When a person (or any other living being such as an animal) dies, the prana, or life force, leaves the body through one of several orifices.

Prana is said to circulate in the body through a system of channels, called nadis (nadi in the singular), which are to prana as veins are to blood.

Prana is a general term which can be further classified into subcategories, referred to as pranas. These are the vital principles of basic energy and subtle faculties of an individual that sustain physiological processes. There are five 'Pranas' or vital currents: Prana, Apana, Vyana, Udana and Samana.

In yoga, pranayama techniques are used to control the movement of these vital energies within the body, leading to an increase in vitality in the practitioner. If Prana enters a period of uplifted, intensified activity, the Yogic tradition refers to this stage of Prana as Pranotthana.

The pranas constitute the second sheath (kosa) of a human being (who is essentially the Atman or the Self). The kosas are listed below

1. Annamaya Kosa (Gross Body)
2. Pranamaya Kosa (Vital Air Sheath)
3. Manomaya Kosa (Mental Sheath)
4. Vigyanamaya Kosa (Intellectual Sheath)
5. Karanamaya Kosa or Anandmaya Kosa (Causal Sheath)

See also

• Upanishads
• Hinduism
• Yoga
• Yoga Sutras