Sweating the details: Sauna's potential health benefits draw scientists' interest

Sauna scientists Dr. Hans Hägglund (from left), Earric Lee and Ashley Mason take a steam in the Japanese sauna at The Well in Oslo, Norway. They are part of a group of international researchers studying the potential health benefits of sauna and other heat therapies. Siv Dolmen for NPR hide caption

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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.