The case of Anna Bågenholm [1] is similarly fascinating. She was in cold meltwater for 80 minutes before being pulled out, and made a ~full recovery. Her core temperature was around 56 degrees when they began resuscitation. It is truly amazing how effective hypothermia is at preserving bodily function!
and to my point, perhaps younger people have better ability to not suffer the ill effects of such temperatures? I am sure many can remember being in snow or sweltering hot weather where adults all went indoors or such. Is it ignorance or something physical?
Ignorance is an interesting question. Does it not bother them because they haven't been conditioned that it bothers them? It makes me think of pain. The anxiety of anticipating pain and of what experiencing the pain will be like is often as or more significant than the pain itself and can cause significant impact on the sufferer's life irrespective of the pain itself. Dogs, on the other hand, do not anticipate the pain, so, even when they hurt, it doesn't have the same impact on their lives.
That's a long way around to get to this: maybe it's not the discomfort of the cold itself that is highly uncomfortable, but the anxiety of the anticipation of what the cold will be like, and that is not something kids have the experience to, well, experience.
I have similar thoughts when playing music, whenever I get a nice sound, I don't feel pain or exhaustion, but every time I fail it suddenly become tiresome.
The brain as an amplifier ?
Maybe I had bad shoes though.
13 c is however an insane body temperature.
After 80 minutes, though, how much difference is there? Still some, I'm sure, but water is really good at conducting heat.