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^ James Mallinson, "Sāktism and Hathayoga," 28 June 2012. Archived 16 June 2013 at the Wayback Machine [accessed 19 September 2013] pgs. 2 "The earliest references to hathayoga are scattered mentions in Buddhist canonical works and their exegesis dating from the eighth century onwards, in which it is the soteriological method of last resort."
^ James Mallinson, "Sāktism and Hathayoga," 28 June 2012. Archived 16 June 2013 at the Wayback Machine [accessed 19 September 2013] pgs. 2 "In its earliest definition, in Pundarīka's eleventh-century Vimalaprabhā commentary on the Kālacakratantra, hathayoga is said to bring about the "unchanging moment" (aksaraksana) "through the practice of nāda by forcefully making the breath enter the central channel and through restraining the bindu of the bodhicitta in the vajra of the lotus of wisdom". While the means employed are not specified, the ends, in particular restraining bindu, semen, and making the breath enter the central channel, are similar to those mentioned in the earliest descriptions of the practices of hathayoga, to which I now turn."
The important role of nutrition in building muscle and losing fat means bodybuilders may consume a wide variety of dietary supplements.[42] Various products are used in an attempt to augment muscle size, increase the rate of fat loss, improve joint health, increase natural testosterone production, enhance training performance and prevent potential nutrient deficiencies.

According to Tattvarthasutra, 2nd century CE Jain text, yoga is the sum of all the activities of mind, speech and body.[6] Umasvati calls yoga the cause of "asrava" or karmic influx[172] as well as one of the essentials—samyak caritra—in the path to liberation.[172] In his Niyamasara, Acarya Kundakunda, describes yoga bhakti—devotion to the path to liberation—as the highest form of devotion.[173] Acarya Haribhadra and Acarya Hemacandra mention the five major vows of ascetics and 12 minor vows of laity under yoga. This has led certain Indologists like Prof. Robert J. Zydenbos to call Jainism, essentially, a system of yogic thinking that grew into a full-fledged religion.[174] The five yamas or the constraints of the Yoga Sutras of Patanjali bear a resemblance to the five major vows of Jainism, indicating a history of strong cross-fertilization between these traditions.[174][note 16]

Yoga may have pre-Vedic elements.[44][45] Some state yoga originated in the Indus Valley Civilization.[50] Marshall,[51] Eliade[9] and other scholars note that the Pashupati seal discovered in an Indus Valley Civilization site depicts a figure in a position resembling an asana used for meditation, Mulabandhasana. This interpretation is considered speculative and uncertain by more recent analysis of Srinivasan[9] and may be a case of projecting "later practices into archeological findings".[52]
If you have high blood pressure, diabetes, or heart problems, ask your doctor what you can do. You may need to avoid certain postures, like those in which you're upside down or that demand more balance than you have right now. A very gentle program of yoga, coupled with a light aerobic activity like walking or swimming, may be the best way to start.