Pranayama (Breath Control)
Pranayama is the measuring, control, and directing of the breath. Pranayama controls the energy (prana) within the organism. Helping promote relaxation and consious direction of energy.
Pranayama is very important in yoga. It goes hand in hand with the asana or pose. In the Yoga Sutra, the practices of pranayama and asana are considered to be the highest form of purification and self discipline for the mind and the body, respectively. The practices produce the actual physical sensation of heat, called tapas, or the inner fire of purification.
As the yogi follows the proper rhythmic patterns of slow deep breathing "the patterns strengthen the respiratory system, soothe the nervous system and reduce craving. As desires and cravings diminish, the mind is set free and becomes a fit vehicle for concentration."