Breath is life we can live for days with out food or water, but deprive us of breath and we die in minutes .in view of this , it is astonishing how little attention we pay in normal life to the importance of breathing correctly. To a yogi there are two main functions of proper breathing to bring more oxygen to the blood and thus to the brain and to control prana or vital energy leading to control of the mind Pranayama the science of breath control consist of exercises especially intended to meet these needs and keep the body in vibrant health.
The nadis are nerve channels or tubes to the astral body through which prana flows Asanas and Pranayama are designed to purify nadis for when they are blocked prana cannot flow freely and poor health results. Yogic breathing or Pranayama revitalizes the body steadies the emotions and creates great clarity of mind. Before practicing the exercises, you should be sure that you understand how to breathe correctly
Making full use of the diaphragm. In order to facilitate the flow of prana and ensure that there is space for expansion of the lungs. Careful breath control with emphasis on exhaling helps use to relax under any kind of tension or stress, most of us are only half breathers. In the strain circumstances of modern life automatic breathing is not sufficient for our needs.