No one likes one frozen butt. So when François Haman tried to recruit subjects into his study of the health benefits of uncomfortable temperatures, he got a lot, well… cold shoulders. And he doesn’t blame them. “You’re not going to attract too many people,” says Haman, who studies heat physiology at the University of Ottawa in Canada.
The human body is simply lousy in the face of cold. “I have done studies where people are exposed to a temperature of 7 degrees Celsius [44.6 Fahrenheit], which is not even extreme. It’s not that cold. Very few people can sustain it for 24 hours,” he said. (Those subjects were even fully clothed: “Mitts, hat, boots and socks. And they still can’t maintain it.”)
People try to keep a space cozy or cool — without shivering and without sweating — by smoothing out temperature variations in indoor spaces. It’s easy to reach for a space heater or scream “Alexa, warm my ass!” when you feel uncomfortable. But you probably shouldn’t tinker with the thermostat too much. There are clearly several reasons for the reduction in heat: About 47 percent American housing burn natural gas for heat, and 36% use electricity, which in the US is still mainly derived from fossil fuels. And there may be other reasons to embrace the cold—health factors that physiologists like Haman have begun to uncover.
Before industrialization, “these extremes were really part of life,” Haman said. Organs deal with cold in winter and heat in summer. “You just keep going back and forth, and back. And this can contribute to metabolic health,” he says.
Researchers know that your body reacts when it’s cold. New fat appears, muscles change, and your comfort level increases with prolonged exposure to cold. But what all this means for modern human health – and whether we can harness the effects of cold to improve it – remain open questions. A series of studies are trying to understand how cold-induced changes in fat or muscle can help prevent metabolic disease, such as diabetes. Another hint is that getting comfortable in the cold is easier than you think — without increasing the heat.
For Haman, these are useful scientific questions because freezing is one of the oldest existing threats to our bodies. “Cold, to me, is [one of] the most compelling stimuli because cold is probably the biggest challenge humans can face,” he said. “Although the heat is challenging, as long as I have water and shade, I will survive quite well. In the cold, the opposite is true.
“If you can’t work together,” he continued, “if you don’t have the right equipment, if you don’t have the right knowledge — you’re not going to survive. Just simple as that. “Finding out how our bodies change in response to such a formidable and ancient adversary provides clues to how they work and how they might work better.
Haman starts everything day with a cold bath or shower. It’s a rush because the cold triggers the body to release hormones called catecholamines, which are involved in the fight-or-flight response. “I really have that feeling about Oh my god, I’m feeling so strong and I’m sober,” he said. “This is my coffee.”