Pran is the life force of the universe coursing through the nerves of our physical body and the nadis (pathways or prana in the system).  Ayurveda and Yoga uses the breath to manage thoughts and emotions, through the practice of pranayama (controlled breath).  It is a powerful healing mechanism affecting the digestion of breath, the digestion of emotions and impressions and the digestion of food along with quieting the mind.

Different types of pranayama have different effects on our health.  The right choice of pranayama depends on many factors such as body constitution, season, purpose (to treat a disease or for meditation) and so on.