Winter-swimming Scandinavian men can teach us how the body adapts to extreme heat and cold:
"Our data underscore that BAT in adult humans is part of the collective body temperature regulation system in collaboration with skeletal muscle and blood flow," says senior study author Camilla Scheel of the University of Copenhagen. "Regular winter swimming combining cold dips with hot sauna might be a strategy to increase energy expenditure, which could result in weight loss if compensatory increase in food intake can be avoided."
In the Denmark-based study, Scheele and her collaborators examined whether the Scandinavian practice of winter swimming is associated with changes in body temperature, resulting in acclimation to both cold and hot challenges. They also looked for differences in brown fat tissue, given its role in producing heat in response to exposure to cold environments.
To explore these ideas, first author Susanna Søberg of the University of Copenhagen recruited eight young male winter swimmers who had alternated several swims or dips in cold water with hot sauna sessions every week for at least two years. For the purposes of this study, winter swimming was loosely defined as swimming or sitting in open water and wearing only swim trunks or nothing. By contrast, the eight control participants did not use any cold or heat therapies during the study and had no history of winter swimming.
"We expected winter swimmers to have more brown fat than the control subjects, but it turned out that they instead had better thermoregulation," Søberg says. In preliminary tests, the participants submerged one hand in cold water for three minutes. While both groups responded to the cold exposure, the swimmers displayed signs of cold tolerance, with a lower increase in pulse and blood pressure. They also had higher skin temperature, pointing to greater heat loss as a potential adaptation to frequent sauna exposure. In another preliminary test, the researchers used an adjustable system consisting of two water-perfused blankets to control and lower the participants' body temperature. Here, the swimmers also showed a higher increase in skin temperature in response to cooling.
Journal Reference:
Susanna Søberg, et al. Altered brown fat thermoregulation and enhanced cold-induced thermogenesis in young, healthy, winter-swimming men Cell Reports Medicine, 2021 (DOI: 10.1016/j.xcrm.2021.100408)
(Score: 0) by Anonymous Coward on Tuesday October 12 2021, @11:06AM (2 children)
"The study's small sample size, the absence of female participants, and the inability to draw causal conclusions about the direct effect of winter swimming on temperature regulation or brown fat tissue are all potential limitations to the findings."
How about do this study with Finnish people. Plenty of real saunas and female winter swimmers here, but we are not Scandinavian.
(Score: 2) by looorg on Tuesday October 12 2021, @12:50PM
It's the look we find something interesting study that can't be used to draw any useful conclusions what so ever.
That said as you note it's hard to say something about this really. While the article doesn't go into any great detail about the 8 participants I assume it was 8 young danish males, or that is the impression I get from the article.
With that in mind it's not hard to find other issues with the study.
Firstly Denmark isn't exactly known for it's cold/winter culture. Danish Sauna culture isn't really a thing as far as I know. It's going to be some fairly weak steam saunas at best. I really don't know how common it is in Denmark. But I have serious doubt it's on the level compared to say Finland or even northern Sweden.
The other factor here might be if it's the "winter swimming" or it's the Sauna before and after that does the trick. I don't know a lot of people, or anyone for that matter, that just does cold swimming and then goes home. There is always Sauna after, and usually also before. Also you normally do it several times going in and out.
Then the type of Sauna might also matter, dry or steam, cause they are quite different. High steam Sauna becomes intolerable quite fast. It's more or less flash boiling.
https://en.wikipedia.org/wiki/World_Sauna_Championships [wikipedia.org]
The link to the actual paper goes nowhere or can't be found as I write this so this is all just based on the article.
(Score: 0) by Anonymous Coward on Tuesday October 12 2021, @05:47PM
>> How about do this study with Finnish people.
The high alcohol levels would be a confounding factor, and even if they controlled for it a significant proportion of the test subjects would kill themselves before winter was over.
(Score: 4, Interesting) by Runaway1956 on Tuesday October 12 2021, @11:49AM (2 children)
OK, obviously, dive suits are out. But does it matter if I'm nekkid, wearing a swim trunk, or wearing T-shirt and shorts, or even a cotton shirt and blue jeans? What about sneakers? Virtually all daily wear clothing is water permeable, and is saturated within a second or two of immersion. Even heavier winter clothes are mostly saturated within 5 to 10 seconds. Go ahead and disqualify some synthetics, such as holofil, and disqualify down filled clothing if you like. Disqualify wool, because wool has unique insulation qualities, compared to other commonly worn textiles.
But that nekkid and/or swim trunks is really unnecessary. You're going to get the same results if you're wearing a business suit when you get dunked into the fjord.
From first hand experience, arctic water rolling across the deck made you feel naked, even in foul weather gear. There aren't enough clothes in the world to keep you warm once you are drenched.
(Score: 3, Insightful) by looorg on Tuesday October 12 2021, @12:56PM
If this is the normal kind, unless they do it differently in Denmark, it's going to require you be naked. No normal person wear clothing for this, or sauna.
I guess you could wear some kind of dry suit but that would probably defeat part of the purpose. But any other suit or piece of clothing might actually be worse if you do wear it as it will retain the water and cling to your skin as you exit the water and walk back to the indoors.
(Score: 2) by EvilSS on Tuesday October 12 2021, @01:44PM
(Score: 0) by Anonymous Coward on Tuesday October 12 2021, @01:08PM (2 children)
Too high might not be such a great thing if you have to spend a long time in the cold. You might want it warm enough so you survive and don't get frostbite but you don't want to be burning more calories than necessary.
(Score: 2) by deimtee on Tuesday October 12 2021, @03:11PM (1 child)
As a survival mechanism, sure. But they are aiming at weight loss. Burning calories unnecessarily is exactly what they want.
If you cough while drinking cheap red wine it really cleans out your sinuses.
(Score: 1, Interesting) by Anonymous Coward on Tuesday October 12 2021, @03:42PM
Maybe they should work on a phone etc charger that works off blood glucose.
There's like 4 grams of glucose in the blood of a 70kg person. About 64000 joules. Take away about 50 joules every second and that's 50 watts, and also an extra 1000 kcal/day.
(Score: 1) by shrewdsheep on Tuesday October 12 2021, @04:08PM (1 child)
A couple of years back, I started to take cold showers. I can confirm that this increases calorie expenditure as I lost weight initially. Apart from being refreshing it makes one more resistant to colds and more tolerant of cold temperatures (it does not feel cold anymore to go outside at minus degrees (Celsius) in a shirt). I still have one cold per year but this used to be two or more. It seems that indeed physiological changes take place (brown fat, mucous immunity).
The following is, however, naive:
A lot of things can be a strategy for weight loss, this being one of the worse ones. If you increase your base load, your intake will automatically increase unless you explicitly control your calorie intake. This OTOH you could have done regardless.
(Score: 0) by Anonymous Coward on Tuesday October 12 2021, @06:54PM
(Score: 0) by Anonymous Coward on Tuesday October 12 2021, @04:46PM
So, how do they compare to the Ukranian twins that the Nazi's swam to death?