Bikram yoga is no more effective at improving heart health than yoga practised at room temperature, new research suggests.
The scientists arrived at the conclusion after studying 80 healthy middle-aged adults who practised yoga over a 12-week period.
The Bikram yoga is a style of practice that is performed in a heated environment, where temperatures are around 40C.
The research team based in Texas found that while Bikram yoga can lower the risk of atherosclerosis, which is a build-up of fatty material inside arteries that causes most heart attacks and strokes, the same effect was also seen among those who practised yoga at room temperature.
Study leader Dr Stacy D Hunter, an assistant professor at Texas State University, said: “Previous studies have shown that sauna therapy and various forms of heat therapy can improve vascular function.
“We decided to do a follow-up study to attempt to isolate the effects of heat and find out whether the heated practice environment was doing anything.”
The participants, aged between 40-60 years, were divided into three study groups: those who practised yoga at 40C, those who practised yoga at room temperature (23C), and those who didn’t perform the exercise at all.
The yoga test subjects took part in 90-minute classes three times a week, while the control group remained sedentary during the same time period.
To see whether both styles of yoga had any effect on the cardiovascular system, the researchers measured the amount of vasodilation (widening) caused by blood flow of a major blood vessel of the upper arm known as the brachial artery, after every yoga session.
Dr Hunter said: “Increases in blood flow causes arterial vasodilation and stimulates nitric oxide production, which has anti-inflammatory properties and can delay the progression of cardiovascular disease, atherosclerosis specifically.
“The amount of vasodilation is indicative of the person’s ability to reduce inflammation and delay heart disease.”
According to Dr Hunter, the team noted similar levels of improvement in the amount of vasodilation in both heated and non-heated yoga practices.
The researchers wrote in the journal Experimental Physiology: “The seminal finding from this investigation was that yoga practised in both heated and thermoneutral environments produced significant improvements in endothelium-dependent vasodilation in middle-aged adults and that there were no differences in the magnitude of the increases between the two environmental conditions.
“These results indicate that the set sequence of 26 postures and two breathing exercises may be the key ingredient in producing favourable changes in endothelial function with yoga.”