Five vital airs are Prana, Apana, Vyana, Udana and Samana.
Prana vayu is the solar or fire energy, It is the flame that flows upward and out. It can specifically be placed in the upper part of the body in the thoracic region. It is responsible for the processes of respiration. It governs speech and the vocal apparatus as well as the respiratory system and the muscles associated with it. This air current gives us the capabilities to absorb sensations, feelings, emotions, and controls manas, the common mind and emotions. The other vayus, even apana derive their energy from this Prana.
Apana vayu is the lunar cool energy, which protects the body from the outside. Associated with gravity, it is linked to cool water that flows downward. However it can be specifically located operating in the lower abdominal region, below the navel and is responsible for elimination through the reproductive and excretory organs, such as the kidneys, colon, rectum, bladder and genitals.
Vyana vayu pervades the whole body and is the power of movement. Vyana governs the relaxation and contraction of all muscles, voluntary and involuntary, as well as the movement of the joints and structures around them in the physical body. That is the reason Ayurveda tells that the joint pain is due to Vayu. Most of us have experienced that the sprain and the pain is reduced by deep breathing several times.
Udana vayu rules the region of the body above the larynx and governs the use of our special inner sense of intuition and is associated with the upward movement of the kundalini or ascending air in the subtle body.Buddhi, or reason, is controlled by this vayu. Udana can be found functioning in the sushumna. It is udana which dissolves prana and apana, stopping their outer and inner flow, in order to bring them together in the middle current, the sushumna, resulting in either samadhi or death.
Samana Vayu is located in the middle region of the body; it facilitates the assimilation of prana and food and has balancing and equalizing effect on prana and apana. It aids in digestion and balance on all levels, physical, mental and emotional. On the physical level, it dwells in the navel, but within the subtle body in the manipura chakra. It is vital energy of the navel where our energy is centered. It increases the digestive fire. The navel is often said to be the main pranic center in which all the pranas are linked together.