Yoga has been seen as a "lifestyle" choice of meditation and diet but now research into the many yoga positions has shown that the body's position, stretching of the muscles, ligaments and contolled breathing all combine to make improvements in the body's functions. The breathing control ensure that the lungs are emptied of waste and stale air, improving oxygen intake, muscle function and muscle contol increases. As you breath in subtle changes take place: you control your diaphram which in turn affects the "core" muscles, as your lungs fill the chest expands, the spine is moved into a more virticle position lifting the head and relaxing the shoulders. Small equipment is used to as tools to help positioning of the body and this helps in the control. Reduced stress is well documented in people who practice yoga.