New findings: What is the central question of this study? Does the heated practice environment enhance the effects of Bikram yoga on endothelium-dependent vasodilatation in healthy, middle-aged adults? What is the main finding and its importance? The primary finding from this investigation is that the hatha yoga postures in the Bikram yoga series produce similar enhancements in endothelium-dependent vasodilatation in healthy, middle-aged adults regardless of environmental temperature. These findings highlight the efficacy of yoga postures in producing improvements in vascular health and downplay the necessity of the heated practice environment in inducing vascular adaptations.
Abstract: We have previously documented improvements in endothelium-dependent vasodilatation with a Bikram (hot) yoga intervention in middle-aged adults. At present, the effect of environmental temperature in hot yoga on endothelial function is unknown. The purpose of this investigation was to determine the effects of Bikram yoga interventions performed in heated or thermoneutral conditions on endothelium-dependent vasodilatation. Fifty-two sedentary but apparently healthy adults aged 40-60 years were randomly assigned to one of three groups: Bikram yoga practised at 40.5°C (n = 19), Bikram yoga practised at 23°C (n = 14) or sedentary time control (n = 19). The yoga interventions consisted of 90 min Bikram yoga classes three times a week for 12 weeks. Endothelium-dependent vasodilatation was measured non-invasively using brachial artery flow-mediated dilatation (FMD). Body fat percentage determined via dual-energy X-ray absorptiometry was significantly lower in the hot yoga group after the intervention than in the thermoneutral yoga and control conditions. Brachial artery FMD increased (P < 0.05) in the thermoneutral yoga group and tended to increase in the hot yoga group (P = 0.056). No changes occurred in the control group. There were no significant differences in FMD change scores between groups. We conclude that Bikram yoga practised in thermoneutral conditions improved endothelium-dependent vasodilatation in healthy, middle-aged adults. These new findings highlight the effectiveness of hatha yoga postures alone, in the absence of a heated practice environment, in improving vascular health and are of clinical significance given the increased propensity for heat intolerance in ageing adults.
Keywords: exercise; hot yoga; thermal therapy; vascular function.
© 2018 The Authors. Experimental Physiology © 2018 The Physiological Society.