The primary aim of yoga is to restore the mind to simplicity and peace, to free it from confusion and distress. This sense of calm comes from the practice of asanas (postures) and pranayama (breathing). Unlike other forms of exercise which strain muscles and bones, yoga gently rejuvenates the body. By restoring the body, yoga frees the mind from the negative feelings caused by the fast pace of modern life. The practice of yoga fills up the reservoirs of hope and optimism within you.

B.K.S. Iyengar – Light on Yoga.