The origins of yoga are a matter of debate. There is no consensus on its chronology or specific origin other than that yoga developed in ancient India. Suggested origins are the Indus Valley Civilization (3300–1900 BCE) and pre-Vedic Eastern states of India, the Vedic period (1500–500 BCE), and the śramaṇa movement. According to Gavin Flood, continuities may exist between those various traditions:
^ James Mallinson, "Sāktism and Hathayoga," 28 June 2012.
^ Housman & Dorman 2005, pp. 303–04. "The linear model supported previous findings, including regular exercise, limited alcohol consumption, abstinence from smoking, sleeping 7–8 hours a night, and maintenance of a healthy weight play an important role in promoting longevity and delaying illness and death." Citing Wingard DL, Berkman LF, Brand RJ (1982). "A multivariate analysis of health-related practices: a nine-year mortality follow-up of the Alameda County Study". Am J Epidemiol. 116 (5): 765–75. doi:10.1093/oxfordjournals.aje.a113466. PMID 7148802.