Exploring the science behind the power of heat as saunas grow in popularity across Ireland

As sauna culture continues to grow across Ireland, Gemma Fullam meets journalist Bill Gifford, whose new book uncovers the science behind the power of heat

“Sweating is magical. Sweating helped us go from the middle of the food chain to the top,” Gifford says, explaining that the evolution of humans’ ability to regulate body heat through sweat helped us segue from prey to predator, enabling us to thrive as a species.

It was a bitterly cold winter in Salt Lake City, Utah, when Bill Gifford first began using the “crap” sauna in his gym. The journalist and writer had been going through a tough time and craved “15 minutes a day of peace and comfort”, which the sauna’s warm, dark, quiet interior provided.

“It felt like an embrace,” says Gifford, who “felt like a new man” after the daily quarter-hour of heat, followed by a 15-second blast under the cold shower. That mood boost set him on a deep dive into the health benefits of heat, which he’s documented in Hotwired: How the Hidden Power of Heat Makes Us Stronger.