The sleeping bag (at least as I've understood it) works in that way, that it uses the heat the body creates to create a layer of heat air between the body and the sleeping bag's border, therefore providing pleasurable feeling of warmth.

But after watching some videos about people such as Wim Hof and scientific research on their body's behaviour, I've found that something quite opposite is taking place there. Their skin is getting very cold, while the body core remains hot. So, there's no pleasurable feeling of warmth, there's no warm air layer, the skin is feeling trembling cold, and the body protects itself from cold isolating the skin from the body core, therefore using skin as isolating layer.

So, when using sleeping bag, the body is not trained to develop such mechanism, because the skin has always contact with warm air, am I getting it right? So, actually, isn't using sleeping bags stopping the body from real accommodation to cold conditions?

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    Adapting to the cold (or the heat) is a long process. I think of it as something I need to try to do in little ways every day. But when I go backpacking/camping I bring the warmest things I can, for temperature. Just IMO. Aug 13, 2013 at 15:51

1 Answer 1


When we get cold vasoconstriction occurs. This prevents the blood at the extremities being subject to heat conduction away from the body. This is not an adaption, this is a reaction.

The body emits heat all the time because the body working and but wants to remain at constant temperature. If the ambient temperature is such that we can lose this heat, we won't get hotter. If it's such that we lose more because it's cold, we will get colder.

Sleeping bags keep us warm by insulating us from the outside world. We would not want to be totally insulated or we'd just get hotter and hotter. Rather, we need the level of insulation to be such that the rate at which we are losing heat is the same as the rate at which it is being conducted and convected away.

This is why we have higher insulation in the winter where rate of heat loss to the environment is higher.

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