Perpetua: The UAH Journal of Undergraduate Research


College of Science


Biological Sciences


It has been hypothesized that sweat loss during exercise causes a disruption in calcium homeostasis leading to bone resorption and low bone mineral density. There is substantial water and electrolyte loss in sweat during hot yoga, an exercise that is becoming increasingly popular with premenopausal women. A Bikram Hot Yoga session typically consists of 26 Hatha Yoga postures that are performed in 90 minutes inside of a room that is set to 105 °F and 40 % humidity. We measured sweat and plasma, electrolyte and water balance before and after a hot yoga session in a population of premenopausal women. Sweat was collected during the final yoga asana by saturating filter paper with sweat from the participants’ thighs to estimate the total amount of electrolyte loss. There was no change in serum sodium or serum osmolarity before or after Bikram Hot Yoga. Mean calcium concentration in serum increased after the hot yoga session. The concentration of parathyroid hormone (PTH) did not change from before to after the hot yoga session; however, a substantial amount of water was lost. This implies that the amount of parathyroid hormone in circulation decreased from before to after. Calcium loss in sweat loss did not trigger an increase in PTH secretion and did not initiate bone resorption. A disruption in calcium homeostasis was not observed in a bout of excessive sweating during a 90-minute Bikram Hot Yoga session. Bikram yoga appears to be a safe practice for premenopausal women as long as fluid and electrolytes are appropriately replenished after the Bikram Hot Yoga Session.



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