Health, as defined by the World Health Organization (WHO), is "a state of complete physical, mental and social well-being and not merely the absence of disease or infirmity." This definition has been subject to controversy, as it may have limited value for implementation. Health may be defined as the ability to adapt and manage physical, mental and social challenges throughout life.
^ On the dates of the Pali canon, Gregory Schopen writes, "We know, and have known for some time, that the Pali canon as we have it — and it is generally conceded to be our oldest source — cannot be taken back further than the last quarter of the first century BCE, the date of the Alu-vihara redaction, the earliest redaction we can have some knowledge of, and that — for a critical history — it can serve, at the very most, only as a source for the Buddhism of this period. But we also know that even this is problematic... In fact, it is not until the time of the commentaries of Buddhaghosa, Dhammapala, and others — that is to say, the fifth to sixth centuries CE — that we can know anything definite about the actual contents of [the Pali] canon."
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.