Prana is a term that we use to describe the vital vital energy that flows within the body. In Yoga we are working with the body and mind to regulate and balance the flow of prana throughout the body. When there are imbalances, it results in illness.
When the flow of energy is regulated and balanced we experience a state of wellbeing both because we have more energy and because the quality of this energy creates a more relaxed and happy state which is more effective at getting things done.
Prana is the life-force that flows through every living thing. It produces movement and work. It allows us to go about our day to day life with sufficient energy. It is the thing that powers life and it flows continuously through our body but also between living creatures and the natural environment.
When prana flows through us, uninhibited by our tensions and attachments, it causes healing for us on a physical, mental and energetic level. By doing dynamic asana (physical postures) we are freeing up the flow of energy within the body.