Trendy hot yoga is no more effective at improving heart health than practicing at room temperature, a new study revealed.
Hot, or Bikram, yoga is increasingly popular around the world and involves 26 poses performed in a room heated to 40°C (104F).
But until now little was known about the health benefits of Bikram yoga, particularly at the stuffy temperature
The study by Texas State University and the University of Texas at Austin was the first to isolate the effects of the heat in Bikram yoga.
It found the heated environment did not play a role in causing improvements in vascular health.
Bikram yoga can reduce changes in the lining of blood vessels that are involved in the development and progression of heart disease.
It also found that it can possibly delay the progression of atherosclerosis, which is a disease in which plaque builds up inside arteries and can cause heart attack or stroke.
However, crucially, it found that it is not necessary for the yoga to be performed at a hot temperature with the effects also being seen at room temperature.
The study involved 80 volunteers who did either hot yoga, "normal" yoga or acted as a control.
The intervention lasted for 12 weeks and participants were asked to attend three Bikram yoga classes per week.
Assistant Professor Stacy Hunter, in the Department of Health and Human Performance at Texas State University said: "The new finding from this investigation was that the heated practice environment did not seem to play a role in eliciting improvements in vascular health with Bikram yoga.
"This is the first publication to date to show a beneficial effect of the practice in the absence of the heat."
The study was published in the journal Experimental Physiology.