The practise of holistic yoga -- like the science of acupuncture, or tai chi and qi gong, is based on prana also known as life force. A key reason you feel better after a hatha yoga class is that the practise of holistic yoga helps move your life force in a way that is balanced and complete. Using the breath through each pose, you are clearing the pathways that distribute life force. The flow of life force is a good explanation for why we feel great after a yoga workout.
