For more on the science of healthy living, try NPR's Health newsletter.Scientists have long marveled at how the human body tolerates extreme heat — and what that means for our health.In the late 1700s, British scientists ran bold experiments on thermoregulation, subjecting themselves (and a dog) to a piping hot room and observing that — unlike the steak and eggs accompanying them — their own bodies did not cook.The acute physiological response to heat is now well understood.Faced with extreme temperatures, our blood vessels dilate, heart rate speeds up and blood is pushed to the skin where it's cooled down as we sweat.Our body releases hormones and activates heat shock proteins that protect our cells.This understanding of our physiology has shaped medical care, for example, with heat-related illness.
However, the other side of the equation — the potential therapeutic benefits of heat exposure — have received considerably less attention from modern medical science.Meanwhile, age-old practices, such as sauna, built around stressing the body with heat are enjoying newfound popularity.From social sauna meetups to the broader wellness and optimization movement, the level of public interest has surprised even long-time devotees like Dr.Hans Hägglund, a hematologist and stem-cell researcher at the Karolinska University Hospital in Stockholm."It's really booming," says Hägglund, dubbed the "sauna doctor" in his home country thanks to a popular book he authored on the subject.
"Unfortunately, there is still not very much evidence out there."At least, not the caliber of studies that Hägglund and other scientists can point to if they want medical societies and government agencies to view sauna and other forms of heat therapy as a bonafide intervention — a lifestyle approach that can be recommended for preventing and treating chronic health conditions.But Hägglund and a small group of international scientists are pushing to make this happen — and organize wh...