Can you get used to the cold?

Brown fat, heat without shivering and what Copenhagen winter swimmers taught researchers.

Turban Sauna // Journal

Many winter bathers say the cold feels different after a few weeks. Research agrees with them, and part of the answer was found here in Copenhagen.

The cold shock gets smaller

The first change comes quickly. The gasp and the racing pulse you feel in cold water grow weaker after only a handful of dips. You can read about that in What happens in your body in the cold plunge. The next change happens deeper in the body and takes longer.

Brown fat: the body’s own heater

Adults carry small amounts of brown fat, mostly around the neck, above the collarbones and along the spine. Brown fat burns sugar and fat to make heat, without any shivering. White fat stores energy. Brown fat spends it to keep you warm.

Ten days in the cold

In a Dutch study, healthy adults spent several hours a day in a cool room for ten days. Afterwards their brown fat was more active, and their bodies made more heat without shivering. The participants also felt the change: the room felt warmer to them, they were more comfortable in the cold, and they shivered less.

The winter swimmers from Copenhagen

Researchers from Rigshospitalet and the University of Copenhagen studied young, healthy men who went winter swimming two to three times a week, with sauna and cold water combined, as many Danes do. In comfortable temperatures their bodies kept a slightly lower core temperature than the comparison group, and their brown fat was at rest. When the cold came, the winter swimmers turned up their heat production more than the others.

The researchers read this as a sign that the winter swimmers had adapted to both heat and cold. Their bodies spend less energy on heat when it is warm and respond faster when it gets cold. The researchers mention a higher energy use as a possible effect. How much that matters in everyday life is still an open question.

What it means for you

Getting used to the cold comes with repetition. Start with short dips, and come back regularly. Heat and cold in turn, the way you do it at TURBAN, is the same combination the Copenhagen winter swimmers used.

If you have a heart condition or are pregnant, talk to your doctor before you start, and read our safety information.

Sources

Søberg et al. (2021): Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men

van der Lans et al. (2013): Cold acclimation recruits human brown fat and increases nonshivering thermogenesis

Barwood et al. (2023): Habituation of the cold shock response