2.) Also notably, neither study nor wiki claim that both brothers had equal resistance to cold.
3.) Lastly, Wim Hof claim is not so much that "gradually increasing exposure" makes him better at cold, his claim is that he found breathing techniques and has batter control over body functions. That may or may not be bullshit, but again, study is not disproving that.
Here I am going to quote exact same study:
> Core temperature decreased in both subjects with a smaller decrease (−0.18°C) in subject A compared to subject B (−0.40°C). As the accuracy of the measurement is ±0.1°C and due to the small range within core temperature is held, we interpreted the difference of −0.22°C as physiologically different. There was a clear difference in cold sensation and comfort between both subjects. [...] Furthermore, subject A reported that he was comfortable with these temperatures during the entire experiment, whereas subject B felt between uncomfortable and very uncomfortable. Cold exposure slightly increased heart rate in subject A (baseline: 46 beats/min versus cold: 52 beats/min), whereas it slightly decreased in subject B (baseline: 51 beats/min versus cold: 47 beats/min).
tldr; some physiological responses were different and one brother felt uncomfortable while the other felt ok.
Edit: here is direct link to study quoted on wikipedia: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4094425/
However I should note that I randomly ended up in one of his workshops years back and he actually did claim that gradually increasing exposure does make you better at cold. It wasn’t the main thing but he did claim it.
> However I should note that I randomly ended up in one of his workshops years back and he actually did claim that gradually increasing exposure does make you better at cold. It wasn’t the main thing but he did claim it.
Ah, ok. I personally find that part uncontroversial, winter swimming clubs are pretty much thing where I live and they claim same thing. The thing I perceived as controversial/disbelieved were breathing techniques, superior body control and wild health benefits. Again, winter swimming clubs here claim health benefits too, but you are supposed to become less vulnerable to common cold and such rather then curing diabetes or cancer.
This claim is true in the broad sense, but not just from gradual exposure. In the Marine Corps, I went through quite a bit of training in dealing with cold conditions. There are specific training requirements for cold exposure, and a tried and true methodology for increasing a person's capacity for dealing with the cold.
Biologically, your body will naturally adjust to a climate over time. This occurs when living in warmer or cooler conditions for a period of time. The main controls are metabolism speed, sweat threshold, and activity level.
One of the key ways to quickly adjust to a new climate is by a forced activity level in it. When we'd train in a new climate, we'd always start by doing forced marches during the peak condition (hottest or coldest time of day, depending on which condition we were unused to) for a day or two, then move on to runs, then to actual mission based training. On the first day or two, we'd all be shivering, miserable, joints swollen, etc... By day 3 or 4, that would all go away. You're still uncomfortable, but your body has adjusted.
Once you leave that climate, your resistance to the extreme temperature slowly fades (as you're adjusting to a new climate), but it seems to me that I still carry a bit of resistance to the extreme.
We'd do refreshers whenever we got the chance, taking people on "polar bear runs" in the middle of the night in the desert, in shorts and t-shirts, and that would help sustain the resistance to the cold.
I really think you don't know what you are babbling about.
The only thing this test might be interpreted as is that the assumption that brown fat correlates with physical cold resistance capabilities might be wrong.