The construction of the Upanishad canon
Many of the Upanishads are clusters of text fragments compiled over generations, if not centuries. Numerous teachers generated them often at the centre of small communities gathering around the philosopher to learn. Some of the teachers were named in the Upanishads, but none of them reached the fame of the two contemporary Kshatriyas Buddha and Mahavira (the last being the founder of Jainism). Soon after the intellectual originator died, many of the teachings and there were hundreds of them (first oral traditions, then later written down) – would have either totally vanished, or only been continued in a very fragmented form. Other teachings would have been picked up by later generations and incorporated in new revised teachings and so on173. Thus there was no comprehensive Upanishad teaching but an arena or discourse of fragmented and contradictory philosophies.
An important point is that many of the Upanishad teachings often just comprising very short essays or tiny collections of verses, were strongly rejected by the majority of the Brahmins. Conservative Brahmins argued that Brahmins were professional ritualists, and should stay away from the abstract speculations and their teaching (Collins 1998). So how does it happen that the Upanishads are seen today as part of original Brahmin teaching? The answer is that, maybe, they were originally not!
Collectively, they suggest that yoga may reduce many IRS- Virabhadrasana III Yoga Pose related [insulin resistance syndrome] risk factors for CVD, may improve clinical outcomes, and Virabhadrasana III Yoga Pose may aid in the management of CVD and other IRS-related conditions. The reported benefits included improved glucose tolerance and insulin sensitivity, lipid profile, blood pressure, oxidative stress, coagulation profiles, sympathetic activation, and cardiovagal function Innes, Bourguignon, & Taylor, 2005. The positive effects of yoga on cardiovascular risk factors probably occur through downregulation of the sympathoadrenal system and the hypothalamic-pituitary-adrenal axis HPA and via stimulation of the vagus nerve leading to increased parasympathetic activity see Chapter 3.
Some of the physical consequences of these changes include decreased heart rate and blood pressure as well as increased heart rate variability HRV and baroreflex sensitivity Brown & Gerbarg, 2005a. Psychological effects include reduction in stress reactivity, perceived stress, anxiety, sleep, and depression. Both the physical and psychological shifts would potentially have positive impact on glucose tolerance, insulin sensitivity, lipid profile, visceral adipose tissue, oxidative stress, coagulation factors, and endothelial function. The net result of any combination of these physiological mechanisms would be reduced risk for cardiovascular disease Innes et al., 2005.