Cold acclimation/adaptation – good or bad?

[Elliott Wolin]

Some friends used to wear summer clothing way into the fall and even winter, supposedly to toughen themselves up for mountaineering trips. I've always wondered if this was a good idea.

Some definitions for discussion below (note…I have no credentials concerning this topic, which is why I'm bringing it up). They concern feeling the cold and actual rate of heat loss:

1) Psychological acclimation – no change in rate of heat loss, you just learn to grin and bear it.

2) Physiological acclimation – no change in rate of heat loss, instead your nervous system becomes less sensitive to the cold so you don't feel it as much.

3) Physiological adaptation – body changes regulation strategy in response to cold and thus lowers heat loss, i.e. the hypothermic response (skin and vascular contractions limit blood flow to extremities, etc.)

4) Anti-hypothermic response -Wim Hof and others apparently can inhibit their hypothermic response and cause their body to generate lots of heat in response to cold. I'll ignore this below since hardly anyone can do it.

Items 1-3 likely operate to varying extents in everyone. My question is whether 1) and 2) are good things to nurture. I.e. wouldn't it be better to be acutely aware of your rate of heat loss rather than suppressing this feeling or knowledge? If you get into the habit of ignoring or not feeling heat loss, convincing yourself everything is fine, then you might find yourself not turning back when you should, or with precious little reserves when you need it.

Or are there other factors at work here I'm ignoring?

[Mitchell Ebbott]

Your concerns with #1 assume that our cold/heat responses are fairly accurate and reasonable to begin with, and acclimation sets our "warning trigger" to a dangerously low level. Another possibility to consider is that access to central heat and A/C has narrowed our range of comfortable temperatures to the point where we might be perfectly safe, yet still feel too hot or too cold.

I have some anecdotal evidence for this. Since moving to Los Angeles, my temperature tolerance range has slid upward by a good 5-10ºF. When I first moved here, 90º heat was stifling and I could barely breathe when it hit 100º. Three years later, I can handle the heat much better but I find myself throwing on a light jacket when it drops below 70º. I'm not just "acutely aware" of my rate of heat loss, I'm over-aware… and I suspect that this is the case, to some degree, for most of us, even those who live in cooler climates.

[Jerry Adams]

similar to previous thread http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=96251

pretty clearly yes, you can acclimitize, require less clothing to prevent hypothermia

[Alpo Kuusisto]

Since this is BackpackingLight, note that if you boost metabolism to do fine with less clothing you need more food. And food is waaay heavier than down. But living outside is sure more comfortable when your body thermoregulates better.

[Jerry Adams]

before your trip, sleep in a cold room with minimal covers, take cold showers,…

then, when you do trip, you'll need less insulation – for comfort or to prevent hypothermia

[Bob Moulder]

After learning to dress properly and — even more importantly — learning to manage clothing to avoid overheating and sweating, the best way to get used to cold is to go out and expose yourself to it as much as possible.

When the first 20-degree days arrived in early winter it felt so cold, even though much exposure to it in the past reassured me that I would get used to it.

So after many winter trips this year it was no surprise that when it got down to 0°F on a recent trip it didn't seem all that cold, and 12°F the next morning felt positively balmy.

In my estimation, it's whole bunch of 1, a good dose of 3, a fair amount of 2 and a little 4 (on a subconscious level) as the season wears on.

[Dan H.]

I'm interested in this matter… is there any scientific data that long term cold adaptation even exists?
The psychological aspect clearly has a huge impact, but I don't believe a physiological (long-term) adaptation happens at all (unless proven wrong).

[Jerry Adams]

there were some links in that other thread, for example

http://www.coolantarctica.com/Antarctica%20fact%20file/science/cold_acclimation_human.php

or

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19890013690.pdf

they're pretty scientific : )

as I remember there was some uncertainty

lots of anecdotal reports

[Dan H.]

thanks, I'll look into that, esp. the first link has sources on the end of the text.

[Anonymous]

Wim Hof

[Author]

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