Post-classical traditions consider Hiranyagarbha as the originator of yoga.[8][9] Pre–philosophical speculations and diverse ascetic practices of first millennium BCE were systematized into a formal philosophy in early centuries CE by the Yoga Sutras of Patanjali.[10] By the turn of the first millennium, Hatha yoga emerged as a prominent tradition of yoga distinct from Patanjali's Yoga Sutras and marks the development of asanas into the full body postures now in popular usage[11] and, along with its many modern variations, is the style that many people associate with the word yoga today.
Hindu monks, beginning with Swami Vivekananda, brought yoga to the West in the late 19th century. In the 1980s, yoga became popular as a system of physical exercises across the Western world. Many studies have tried to determine the effectiveness of yoga as a complementary intervention for cancer, schizophrenia, asthma and heart patients. In a national survey, long-term yoga practitioners in the United States reported musculo–skeletal and mental health improvements.[12]
As opposed to the traditional practice, physical focus on yoga became popular in the West beginning in the second half of the 20th century, and is often referred to simply as "Hatha Yoga" in the context of yoga as physical