The popular belief that hot yoga offers more health benefits than yoga practiced at room temperature does may be a stretch, a new study led by researchers from Texas State University and UT-Austin suggests.
Bikram yoga is a popular form of yoga that is often practiced in hot and humid conditions, usually at temperatures around 100 degrees Fahrenheit. Bikram yoga enthusiasts say that it provides metabolic and cardiovascular benefits.
“People use the word ‘detoxing,’” said Stacy Hunter, a professor of exercise and sports science at Texas State University. “There is some belief that (hot yoga) does detoxify the body, and that sweating and exposing the body to heat is somehow healthy or beneficial.”
Researchers recruited participants between 40 and 60 years old, who are at higher risk of vascular disease and dysfunction. One group of participants completed the standard 90-minute bikram yoga classes at 100 degrees Fahrenheit, while another group completed the same classes at room temperature.
To evaluate the effects of bikram yoga on heart and vascular health, the researchers assessed endothelium-dependent vasodilation. Endothelium-dependent vasodilation is the widening of blood vessels that occurs due to changes in the endothelium, or the layer of cells that lines the inner surface of blood vessels. Greater vasodilation results in more relaxed blood vessels and lower blood pressure, which means that vasodilation can serve as a marker of cardiovascular health.
Hirofumi Tanaka, a UT-Austin professor of kinesiology and health education, said endothelium-dependent vasodilation is also a useful marker to study because researchers can quickly observe changes in it.
“If you’re looking at cardiovascular disease as an outcome, it’s a long-term process,” Tanaka said. “You have to follow them for years to see (the effect). But vascular function, and specifically the vascular response we were looking at, is very quick. So you can actually show the benefits if there are any in a short period.”
While both the groups that performed bikram yoga showed improved vasodilation from baseline, the researchers found no difference in vascular health between the two groups. In other words, practicing bikram yoga in a heated environment didn’t give significantly more vascular benefits than practicing bikram yoga at room temperature did.
“The primary message is that you don’t have to do that kind of exercise in that hot, humid environment,” Tanaka said. “If you do it at room temperature, you can get similar benefits.”
Hunter said the added heat during exercise can also pose a health threat to certain groups that are at risk for heat illness or stroke. Doing bikram yoga at room temperature may be safer and offer the same health benefits.
Hunter, however, cautioned against generalizing the effectiveness of the added heat to all forms of yoga.
“There would have to be more studies to examine the same phenomenon with other styles of yoga outside of bikram,” Hunter said. “Bikram isn’t the only style that’s practiced in heat.”