Is it possible to acclimatize to a cold weather in a short time?

Question

On some of my Himalayan treks I've seen people who wear shorts or wear single layer of clothing and shiver due to the cold weather (most of these people live in a tropical climate). When I've asked what they've been up to, the answer I've always received is that they are getting their bodies used to the cold weather. While I personally have felt this is foolishness (and I always end up wearing multiple layers), are these people really onto something? Does it help to help to expose yourself to the elements thereby help your body to get used to the cold weather in a short period of time?

If not, is there a way one can prepare beforehand to get used to the cold weather? (based on a comment, maybe take cold showers everyday?)

Answer 1

For these kinds of issues I like to look at how militaries handle it, since they are heavily invested in optimizing personnel performance in a wide range of climates and conditions. Some anecdotes from looking into that in the past, I don't have a citation for now: it is more difficult to acclimate to cold than to warm temperatures, and people adapting from warm to cold are more likely to have their immune system weakened and more health problems than people adapting from cold to warm.

Here's an OK reference: Interactive Military Training Tools & Software There are 3 main takeaways:

• Acclimation in general (for any extreme climate) is more rapid with moderate activity. However, because your body is already strained with acclimation, I think you're better off also making sure to get sufficient rest, hydration, and nutrition (maybe even better than normal) to help your body handle the added stress.
• "Hypothermia develops when the body cannot produce heat as fast as it is losing it." "During exercise in the cold, people usually produce enough heat to maintain normal body temperature. As they get fatigued, however, they slow down and their bodies produce less heat." For this reason I would not recommend exposing yourself to high heat loss in very cold environments (i.e. don't wear shorts and a T-shirt); conserve heat with smart clothing.
• "Frostbite is the freezing of body tissue. It commonly occurs in body parts located away from the core and exposed to the cold such as the nose, ears, feet, hands, and skin." "Also, people often overdress for exercise in the cold. This makes the body sweat. The sweat dampens the clothing next to the skin making it a good conductor of heat. The combination of decreased heat production and increased heat loss can cause a rapid onset of hypothermia." Again, smart clothing is important here for preventing loss of warmth in body tissue do to exposure to wind or moisture/sweat.

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Physical acclimation takes time but it can be enhanced by moderate activity and helping boost your body's ability to adapt to stress (through basics like sleep, hydration, etc.) Therefore it is probably not a good idea to spend the day underdressed as this will only add stress and increase your risk of temperature-related injury.

Psychologically myself and others do find short-term controlled exposure to stress can help acclimate us to stress itself. For example, exposing yourself to stressful temperatures with the intention of remaining calm during exposure, only for a short time (longer if you can remain exercising and not fatigued) before incurring any injury. This helps the mind acclimate to stress, but the body still needs time to physically acclimate to extreme temperatures, adjusting metabolism and other features. If you do 'stress test' yourself regularly with extreme temperatures, this may have physical effects on your ability (including time needed) to acclimate to extreme climates (a la Whim Hoff), but I'm not aware of any rigorous evidence of that. Keep in mind, in general, being more physically fit reduces the time you need to physical acclimate.

For short expeditions, psychological acclimation may be more important than physical acclimation. Still, during the expedition, it doesn't make sense to sacrifice too much physical capacity just to gain more mental capacity when you will be putting your body through a lot of physical stress already.

Answer 2

Roald Amundsen, the arctic explorer, would stand by his open window without a shirt from the time he was 11 or 12. Myth or fact?

Personal experience, living in a climate with big changes between summer and winter: The first cold days of winter seem bitter. At -10C I would have toque, mitts, polypro, windbraker. By winter's end this was mild, and I'd think nothing of going to get a sled of wood (100 m each way) in t-shirt.

Either the Swiss or the Scandinavians did some research where they paid college students to sleep on a wooden deck above a glacier in fall with just a sheet. Temps were in the single digits by morning. My recollection of the report was that no-one got much sleep the first night or two. By night 3, their metabolism had ramped up enough that they were comfortable -- well as much as you can be sleeping on a wood deck. Can't find it now.

Guys who work in the commercial winter ice fishery on Lake Winnipeg, have hands constantly wet from handling the nets and the fish. Yes they wear gloves, but that's mostly for grip, (fish are slippery) and to slow the heat loss some. But they put their hands IN the water to warm them up, and to melt the ice that forms on/in the gloves. So zero degree water is considered warm to the wind and sub freezing temps in the air.

That said: People who spent the first two years of their lives in hot climates tend to develop more sweat glands than do people in chilly climates. Sweat glands never completely shut down, so to some degree they never adapt as well. For reverse reasons, polar folk don't do well in humid tropical climates. I'm appalled at even the thought of a Toronto summer.

So, yes I think being shivering cold does adapt you to a colder regime.

In passing: At near freezing temperatures humidity has a big effect. Fog seems much colder than clear air, which feels somewhat colder than dry air.

Wind is critical. Even a light breeze has a very large effect. Wind chill calculations don't do justice to that first 5 kph. A good wind parka is more significant in my experience than a good fleece in staying comfortable, expecially if you are engaged in aerobic activity. E.g. A wind parka over polypro underwear is sufficient, where two fleeces is not when snowshoeing across rolling hills in central Alberta at -20 C

Sun is critical. The presence/absence of sun is equivalent to about 10 C in terms of how I dress for working outside.

Answer 3

This will depend a lot on the individual.

Some people may be able to acclimatize quickly, others will not. In parts of Western Canada the temperature is regularly +30°C in the Summer and -30°C in the winter, so the people here have to adapt to both extremes every year.

How effectively you adapt to the climate often depends on your upbringing. Your body learns to adapt to its environment pretty well while it's developing, so kids raised in an environment will have a much easier time adapting to that environment than an adult who moves from one environment to another.

It may be possible for some people to train their bodies to adapt to a colder environment at a quicker rate, but in my opinion freezing your butt off in shorts to adapt to the cold quicker is less about adaptation and more about relativity. A classic example is the kid who complains about the house being cold. Their tough-love daddy sends them outside in the freezing cold for a few minutes, then when they come inside the house suddenly feels a lot warmer than it did before they went outside. Your friend might think he's adapting to the cold, but really he's just freezing himself to the point that when he puts his good layers on they feel way warmer than he remembers.

One way to help control your body temperature is to watch the number of calories you consume. Food is like fuel on the fire, if you're cold, eat more, if you're too hot, don't eat as much; your body will allocate the calories appropriately. I eat way more in the winter than I do in the summer. There's lots of times in the summer where I won't eat at all because it's too hot, but this may be because my body has adapted to converting a lot of calories into body heat in the winter times.

As a cold climate dweller, and an ice climber, I don't try to fight the cold, I defend against it, if I'm cold, I dress up or eat something and move around to warm up. No one I know indulges in any kind of "exposure" or "temperature" training foolishness.

Answer 4

Research has established that humans adapt well to heat.

Adaption to cold is a more controversial topic, but according to this literature survey any benefit from cold training is small and unreliable, varying from individual to individual.

So I wouldn't bother making the attempt - focus on developing an effective clothing system instead.

Answer 5

About 12 years ago, I moved from Britain to Finland, just in time for one of the coldest Februaries on record for Helsinki. Most days were -20°C, with some at -25°C, once the moderating influence of the nearby Baltic Sea was removed by it freezing over (which it does most years). Finnish offices and homes are fantastically well insulated and heated, but I still had to go outside to travel between them, to shop, and to explore the city.

I had, however, planned ahead sufficiently to bring appropriate winter clothing - not quite of Arctic standard, but much warmer than you'd normally wear in Britain (unless hiking in the Highlands during winter, perhaps). That meant a fleece jacket under a weatherproof one, long-johns under my trousers, double socks and gloves, and a turtleneck scarf which overlapped a woolly hat over my ears. I already habitually wore soft, waterproof hiking boots, and continued to do so.

Conversely, my employer entertained visitors from a customer - who also happened to be from Britain - that month, and they were much less well prepared. They wore standard urban winter clothing for the southern half of England, which has a considerably milder climate than Helsinki. That meant a weatherproof jacket, a woolly hat, and a pair of gloves - that's all.

My employer ended up having to guide them to a local clothing shop to supplement their equipment, since they were absolutely miserable every time we went outside, despite their hotel being only a few hundred yards away. Meanwhile, I was entirely comfortable in my slightly-overkill choice of clothing, even though it was fully 15-20 degrees colder than weather I'd previously considered "wintry", and I'd had less than a month to acclimatise.

By contrast, on the few occasions when I've visited a warm country, I've found myself overheating very easily, despite wearing as little as I felt was compatible with modesty and avoiding sunburn. For that reason among others, I don't go south for my holidays.

So my advice is: it's easier to adapt to a cold climate than a hot one. If you feel cold, just put on more clothes!