Yoga is probably the world's most perfect form of exercise. It cultivates cardiovascular health, and musculoskeletal strength and flexibility, without the painful and damaging side effects of high-impact aerobics. It tunes up every organ system — respiratory, digestive, reproductive, endocrine, lymphatic, and nervous. It cultivates the body's capacity to relax and dramatically reduces the negative effects of stress. With regular yoga practice, we breathe better. We sleep better. We digest our food better. We feel better. We may even begin to recover from chronic illness. And, for many Americans, the best part is that none of these amazing outcomes requires long years of training and apprenticeship. The benefits of practice are immediate. We are, by and large, a very practical people. And yoga is a very practical endeavor.
— Stephen Cope, Yoga and the Quest for the True Self