The Yoga Sutras are also influenced by the Sramana traditions of Buddhism and Jainism, and may represent a further Brahmanical attempt to adopt yoga from the Sramana traditions. As noted by Larson, there are numerous parallels in the concepts in ancient Samkhya, Yoga and Abhidharma Buddhist schools of thought, particularly from 2nd century BCE to 1st century AD. Patanjali's Yoga Sutras is a synthesis of these three traditions. From Samkhya, the Yoga Sutras adopt the "reflective discernment" (adhyavasaya) of prakrti and purusa (dualism), its metaphysical rationalism, as well its three epistemic methods of gaining reliable knowledge. From Abhidharma Buddhism's idea of nirodhasamadhi, suggests Larson, Yoga Sutras adopt the pursuit of altered state of awareness, but unlike Buddhism's concept of no self nor soul, Yoga is physicalist and realist like Samkhya in believing that each individual has a self and soul. The third concept Yoga Sutras synthesize into its philosophy is the ancient ascetic traditions of meditation and introspection, as well as the yoga ideas from middle Upanishads such as Katha, Shvetashvatara and Maitri.
The first Hindu teacher to actively advocate and disseminate aspects of yoga, not including asanas, to a western audience, Swami Vivekananda, toured Europe and the United States in the 1890s. The reception which Swami Vivekananda received built on the active interest of intellectuals, in particular the New England Transcendentalists, among them Ralph Waldo Emerson (1803–1882), who drew on German Romanticism and philosophers and scholars like G. W. F. Hegel (1770–1831), the brothers August Wilhelm Schlegel (1767–1845) and Karl Wilhelm Friedrich Schlegel (1772–1829), Max Mueller (1823–1900), Arthur Schopenhauer (1788–1860), and others who had (to varying degrees) interests in things Indian.
The Maitrayaniya Upanishad, likely composed in a later century than Katha and Shvetashvatara Upanishads but before Patanjali's Yoga Sutra, mentions sixfold yoga method – breath control (pranayama), introspective withdrawal of senses (pratyahara), meditation (dhyana), mind concentration (dharana), philosophical inquiry/creative reasoning (tarka), and absorption/intense spiritual union (samadhi).
Personal health depends partially on the active, passive, and assisted cues people observe and adopt about their own health. These include personal actions for preventing or minimizing the effects of a disease, usually a chronic condition, through integrative care. They also include personal hygiene practices to prevent infection and illness, such as bathing and washing hands with soap; brushing and flossing teeth; storing, preparing and handling food safely; and many others. The information gleaned from personal observations of daily living – such as about sleep patterns, exercise behavior, nutritional intake and environmental features – may be used to inform personal decisions and actions (e.g., "I feel tired in the morning so I am going to try sleeping on a different pillow"), as well as clinical decisions and treatment plans (e.g., a patient who notices his or her shoes are tighter than usual may be having exacerbation of left-sided heart failure, and may require diuretic medication to reduce fluid overload).
Pre-philosophical speculations of yoga begin to emerge in the texts of c. 500 – c. 200 BCE. Between 200 BCE and 500 CE, philosophical schools of Hinduism, Buddhism, and Jainism were taking form and a coherent philosophical system of yoga began to emerge. The Middle Ages saw the development of many satellite traditions of yoga. Yoga came to the attention of an educated western public in the mid 19th century along with other topics of Indian philosophy.
The Yoga Yajnavalkya is a classical treatise on yoga attributed to the Vedic sage Yajnavalkya. It takes the form of a dialogue between Yajnavalkya and Gargi, a renowned philosopher. The text contains 12 chapters and its origin has been traced to the period between the second century BCE and fourth century CE. Many yoga texts like the Hatha Yoga Pradipika, the Yoga Kundalini and the Yoga Tattva Upanishads have borrowed verses from or make frequent references to the Yoga Yajnavalkya. The Yoga Yajnavalkya discusses eight yoga Asanas – Swastika, Gomukha, Padma, Vira, Simha, Bhadra, Mukta and Mayura, numerous breathing exercises for body cleansing, and meditation.
Yoga gurus from India later introduced yoga to the West, following the success of Swami Vivekananda in the late 19th and early 20th century with his adaptation of yoga tradition, excluding asanas. Outside India, it has developed into a posture-based physical fitness, stress-relief and relaxation technique. Yoga in Indian traditions, however, is more than physical exercise; it has a meditative and spiritual core. One of the six major orthodox schools of Hinduism is also called Yoga, which has its own epistemology and metaphysics, and is closely related to Hindu Samkhya philosophy.