Effects of Heated versus Thermoneutral Bikram Yoga Interventions on Endothelial Function and Arterial Stiffness

Abstract

Bikram (hot) yoga is a style of hatha yoga practiced at 40.5° C with 40–60% relative humidity. We have previously documented improvements in endothelium‐dependent vasodilation but not arterial stiffness in healthy, middle‐aged adults with an 8‐week Bikram yoga intervention. Currently, it is unknown whether the effect of hot yoga on endothelial function might be attributed to the hatha yoga asanas or the high temperature/humidity. It is also unknown whether a longer intervention might produce significant alterations in arterial stiffness.PURPOSEThe purpose of this investigation was to determine the effects of a 12‐week Bikram yoga intervention performed in standard heated conditions and in a thermoneutral environment on endothelium‐dependent vasodilation and arterial stiffness.METHODSFifty‐two sedentary but apparently healthy adults aged 40–60 years were randomly assigned to one of three groups: Bikram yoga practiced at 40.5°C (n=19); Bikram yoga practiced at 23°C (n=14); or sedentary time‐control (n=19). The 12‐week yoga intervention consisted of 3 weekly 90‐minute Bikram yoga classes. The time control group was instructed to maintain current lifestyle patterns for the study duration. Body composition was determined via dual energy x‐ray absorptiometry (DXA). Endothelium‐dependent vasodilation was measured noninvasively using brachial artery flow‐mediated dilation (FMD) after 5 minutes of blood flow occlusion. Arterial stiffness was measured via brachial‐ankle pulse wave velocity (PWV).RESULTSAge, anthropometric variables, plasma lipid, glucose, and triglyceride concentrations, brachial artery FMD and brachial‐ankle PWV were not different among the three groups at baseline. Body fat percentage declined (p<0.01) and total‐ (p=0.051) and LDL‐cholesterol (p =0.09) concentrations tended to decline only in the hot (40.5°C) yoga group. Brachial artery FMD increased (P<0.05) in both yoga groups but brachial‐ankle PWV was not significantly altered in any group. There were no changes in any outcome variables in the time control group.CONCLUSIONSBikram yoga practiced in hot/humid and thermoneutral conditions produced similar improvements in endothelium‐dependent vasodilation in healthy, middle‐aged adults. The addition of the heat led to reductions in body fat percentage. Bikram yoga does not appear to modulate arterial stiffness in middle‐aged adults.Support or Funding InformationThis study was funded by Pure Action, Inc. Austin, TX, USAThis abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.