A while ago I read (maybe even here somewhere) that some people are able to generate body heat pretty much at will. Is this possible? How does it work, does the whole body heat up or just limbs? Could one warm up only hands or feet? Does it depend on season? Perhaps most important, is it a learnable skill or an inherent thing?
When it’s involuntary, it’s called shivering.
When it’s voluntary, it’s called exercise (or manual labor). metabolic activity generates heat. Want more heat? Engage in more activity. Your muscles do mechanical work, but because they are not 100% efficient, they produce some waste heat at the same time.
Instead of real exercise (like jumping jacks or jogging), it’s possible to tense up your whole body and shiver on a voluntary basis. Maybe that’s what you’re thinking of?
Buddhist monks can do this, but it’s actually a side effect of a specific type of meditation. I have read of Buddhist initiates being tested, in the high Himalaya regions, by having to dry cold wet sheets, using only their body heat, while sitting on frozen lakes meditating. It’s how monks are able to exist in high altitude caves, on a meagre diet, with only a robe to wear. And it has been studied, since it’s been so well documented.
I think what the OP is asking about is more analogous to blushing, except in parts of the body other than the face.
As I understand it, blushing can redistribute heat within the body (via redistributing blood flow), but doesn’t particularly produce any extra heat - that is, the body’s overall average temperature remains pretty much the same.
Assuming the monks can indeed generate heat on demand, this heat won’t come magically from the aether. It comes from the foods they eat. A meager diet is only going to make things worse.
Lewis Gordon Pugh is the man - he is able to trigger anticipatory thermo-genesis - the ability to raise his core temperature by 2[sup]o[/sup]C - he claims that this is a pavlovian response to many years of extremely cold swimming events. This ability has not be shown in any other individual.
Here is an excellent paper on the Buddhist practice - called tummo meditation:
Thanks, that’s the kind of heat generation I’m curious about.
Reading that article, it is clear that the primary mechanism for elevating temperature is isotonic muscle exercise in conjunction with rapid energetic breathing (Fast “Vase” breathing) - i.e. the sitting still equivalent of jumping jacks.
There may be some value in the meditative aspects for extending the period of thermogenesis. But the primary process appears to be isostatic exercise (i.e without movement).
My karate was very keen on winter training , everybody assumes isotonic muscle exercise is part of it but we just relaxed and used some visualization whilst meditating under a waterfall, I’m not sure you even need the visualization and no one every told me the secret mantra most people swear you need.
“Pull my finger.”