The physical practice of yoga is to strengthen the body and make it pain and disease free so the mind is not distracted from meditation. In my experience yoga does a fantastic job of strengthening the organs and improving vital functions. Coupled with pranayama (proper breathing) yoga removes toxins and purifies our blood. Most of all it prepares our body to be still and enter into deeper meditation.
In fact I believe yoga is a lifestyle choice and a serious student of yoga should also incorporate yogic diet and compassionate living. Walk in your truth and live an authentic life.