Proponents claim the hot, humid workout, which puts sweaty participants through a series of 26 poses, burns more calories than yoga performed at room temperature, and is better at flushing out toxins.
Others have pointed to potential dangers such as dehydration and heat stroke.
A study published in the journal Experimental Physiology found that yoga was beneficial regardless of whether it was done in a hot room or at ambient temperature.
Both forms reduced changes in the lining of blood vessels that can lead to heart disease, and appeared to delay the progression of plaque build-up in arteries that can cause heart attacks or stroke.
The findings highlight yoga’s effectiveness “in the absence of a heated practice environment, in improving vascular health,” the study authors wrote.
The findings were important, they added, “given the increased propensity toward heat intolerance in ageing adults.”
The team enrolled 52 “sedentary but apparently healthy” adults aged 40-60 for the trial.
They were divided into three groups, two of which did yoga three times a week for 12 weeks, and a third “control” group which did none.
One of the yoga groups exercised in a room heated to 40.5 C, the other at 23 C.
“The heated practice environment did not seem to play a role in eliciting improvements in vascular health with bikram yoga,” said study co-author Stacy Hunter of Texas State University.
