Freezing is one of our bodies’ oldest existential threats

Sunday, January 9th, 2022

I recently listened to the audiobook version of The Worst Journey in the World, Apsley Cherry-Garrard’s memoir of the 1910–1913 British Antarctic expedition led by Robert Falcon Scott. It didn’t go well. That said, they seemed to find blizzard conditions in Antarctica perfectly survivable, if they could just wait out the storm in their tents, with fuel to burn and other warm bodies around them.

I was thinking off this as I read a Wired article asking, could being cold actually be good for you?

The human body is simply lousy at facing the cold. “I’ve done studies where people were exposed to 7 degrees Celsius [44.6 Fahrenheit], which is not even extreme. It’s not that cold. Few people could sustain it for 24 hours,” he says. (Those subjects were even fully dressed: “Mitts, a hat, boots, and socks. And they still couldn’t sustain it.”)


Before industrialization, says Haman, “these extremes were actually part of life.” Bodies dealt with cold in the winter and heat in the summer. “You kept on going back and forth, and back and forth. And this probably contributed to metabolic health,” he says.

Researchers know that your body reacts when it’s cold. New fat appears, muscles change, and your level of comfort rises 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 — are still open questions. One vein of research is trying to understand how cold-induced changes in fat or muscle can help stave off metabolic disease, such as diabetes. Another suggests it’s easier than you might think to get comfortable in the cold — without blasting the heat.

To Haman, these are useful scientific questions because freezing is one of our bodies’ oldest existential threats. “Cold, to me, is [one of] the most fascinating stimuli because cold is probably the biggest challenge that humans can have,” he says. “Even though heat is challenging, as long as I have access to water, and to shade, I will survive fairly well. The cold is completely the opposite.”

“If you’re not able to work together,” he continues, “if you don’t have the right equipment, if you don’t have the right knowledge–you’re not going to survive. It’s as simple as that.”


Haman has since shown that braving the cold can teach your body to stockpile more of it. In 2013, he asked his subjects to wear “cold suits” circulating water at 10 degrees Celsius (about 50 Fahrenheit) two hours a day, five days a week, for four weeks. It was cold and uncomfortable, but this “low intensity, long duration” acclimation caused people to double their amount of brown fat, which appeared around the spinal column, adrenal glands, and pelvic muscles.

Once it appears, brown fat doesn’t just sit around: Its activity replaces shivering as the body’s go-to heat factory. “Everything is being compensated by nonshivering thermogenesis,” says Haman. For the participants in the study, wearing the cold suit also tripled how active that fat was, or how much it burned. Shivering decreased about 10 to 20 percent after acclimating, according to his study. In other words, he concluded that the subjects acclimated to the cold by producing more brown fat, which in turn made them more comfortable at lower temperatures, without needing to shiver.

Then, in 2019, Haman aimed higher. Or perhaps lower. He recruited seven men to undergo seven days of intense cold acclimation. Each day, they sat in 58-degree-Fahrenheit water, submerged up to their clavicles, for up to one hour, until their core temperatures dropped to 95 degrees. They were then dried and slowly warmed back up. “It’s basically an hour of, uh … not having fun,” Haman says. “But after seven days, you’re basically a totally different person.” Participants could go an hour longer before shivering than they could before the trials. And they would shiver 36 percent less intensely, on average.


After the brown fat discoveries in 2009, Joris Hoeks, a diabetes researcher at Maastricht University in the Netherlands, was curious about its role in controlling blood sugar. His team recruited people with type 2 diabetes for a cold acclimation study. An important hallmark of type 2 diabetes is insulin resistance, in which organs take up less sugar from the blood. Participants endured six hours of cold, right on the edge of shivering, for 10 days. Their sensitivity to insulin, a key hormone in controlling blood glucose, improved by 43 percent on average — a boost comparable to the effect of a 12-week workout program.


Muscle cells change in the cold. Proteins responsible for transporting glucose fuel into muscle cells appear to migrate toward the outside of the cell. Hoeks thinks that change may help the body process more glucose, either because of mild or unnoticeable shivering contractions, or some other muscle process altogether.


  1. Adar says:

    U.S. Army officers during their career are normally expected to complete either jump school [parachuting] or as alternative winter warfare training. Such schools act as a filter mechanism to separate weak from strong. Winter warfare may seem a poor alternative to parachuting but perhaps not so.

  2. Bruce Purcell says:

    In one of Alexis Gilliland’s Rosinante trilogy books, a doctor implants brown fat in a woman and cures her chronic backaches.

  3. Nels says:

    See Wim Hof and his trip up Mt Everest.

    Yes, you can train for the cold.

  4. Mike in Boston says:

    See also the Scandinavian moms who bundle their babies up, put them in a baby carriage, and park them outside to acclimate to the winter cold while keeping watch through a window.

  5. Lucklucky says:

    It is known that in the Falklands War the injured survival rate was higher due to cold weather.

  6. ETat says:

    Mike in Boston, I’m not Scandinavian, but I did the same for my 6-month-old son in our Ural-region city. I bundled him up, put him in a baby carriage, and wheeled him out to the balcony at –15°C. I read about it in a book on early-childhood immune training.

    He would fall asleep immediately, and then I’d roll him back in in an hour (progressing up to two hours). He was warm inside but breathed fresh frosty air. HE did not sneeze once that whole first year of his life.

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