With England becoming colder than Greenland, perhaps we could take a few tips from the Inuit people, who have been coping with freezing temperatures for thousands of years. How do they do it, and could science do any better? Len Fisher looks at the science of traditional ways of coping with the cold.
Adapting Your Body
EskimoWhen your body starts to feel the cold, its first response is to protect the “core” i.e. the brain and internal organs, which need to stay at a temperature of 37ºC for optimum functioning. The way that your body handles this problem is by shrinking the blood vessels near the skin to reduce superficial blood flow by up to ten-fold, so that the loss of heat to the outside is minimized. This protects the core, but at the expense of the skin and surface tissues, which rapidly become blue as they lose the pinkness associated with normal blood flow. The extremities of your body (your toes, fingertips and nose) are the worst affected, and it is these that are in the most danger. If the situation is allowed to continue, chilblains will follow, and even frostbite.
Inuit people overcome the effects of the cold on their extremities by a remarkable genetic adaptation in which their bodies cycle the level of vasoconstriction (i.e. the shrinkage of the blood vessels) so as to keep their fingers and toes safe from cold damage while not losing too much heat. A physicist’s solution would be to take a warm drink every so often, heating up the core sufficiently for it to send a message to restore full circulation to the surface blood vessels. If that’s not sufficient, one can at least slow down the loss of heat from the extremities by wearing gloves and warm socks.
Mind Your Head
The most sensitive place for loss of heat is the head, with its massive blood circulation. Even a decrease of half a degree in brain temperature can produce warning signals. With some 30% of our total heat loss coming from our heads, it’s obvious that this is a particularly critical area.
The simple answer is to wear a hat; the warmer and woollier, the better. The Inuit make them from seal, walrus or caribou skin. If you have to make one yourself when unavoidably exposed to extreme cold, any insulating material will do. Bubble wrap is a good alternative to seal skin, and a layer of aluminium foil on the outside will make it even more effective by reflecting any transmitted heat back to the head. You may look like a spaceman, but that’s better than being completely spaced out.
Use Your Refrigerator to Keep Warm
The environment in an Inuit igloo is rather colder than that inside a domestic refrigerator. Igloos are “warmed up” by an oil lamp to around 0ºC, whereas the temperature inside a typical domestic refrigerator is around 4ºC. I am not suggesting, though, that you crawl inside your refrigerator to get warm. There is a better way to use it, which is simply to stay in the kitchen with the doors closed (including the door of the refrigerator). The point is that a refrigerator is a heat pump, extracting heat from the food inside and pumping it out the back. It’s quite an efficient heater when used in this way, and a kitchen is usually a small enough room to be warmed significantly by its output.
Choose Your Body
People such as myself, who fit the euphemistic description “short and stocky”, are better off than those who are tall and thin when it comes to coping with the cold. The reason is that our surface areas are relatively small compared to our volumes, so that we lose less heat in proportion to our size. “Short and stocky” also implies the presence of an insulating layer of subcutaneous fat. Contrary to the popular image, however, many Inuit people are not short and stocky, and most possess only a “moderate” amount of subcutaneous fat (except those who have been living in close contact with Western culture!). What Inuit people do have is an unusual distribution of subcutaneous fat, which is distributed all over their bodies, including the fingers. This lets them operate in an icy environment with bare hands, which is something that we can only do if we use insulating gloves that perform the same thermal function as the fat.
Wear Your Clothes in Layers
The Inuit design their clothing in a manner whose efficiency scientists have only recently begun to understand. Inuit hunters wear annuraaqs (the forerunner of our anoraks) made from two layers of Caribou skin, with the hairs on the inner layer facing towards the body and the hairs on the outer layer on the outside of the garment.
The hairs on the inside aren’t just there to make the hunter feel itchy and keep him awake. They serve a dual purpose of trapping a thin layer of air next to the skin (stagnant air is a very efficient insulator) and of “wicking” perspiration away from the skin. The latter action is especially important. Water conducts heat away from the body 25 times as efficiently as air, so it is very important to keep the skin dry.
The caribou skins themselves act as a “middle” layer, with both the two layers of leather and the still layer of air in between acting as insulators. It is the hairs on the outside, though, that provide the real surprise. They are not there only to insulate, but to provide an outer “windbreak” that breaks up the flow of wind so that it can’t get at the insulating layers below to carry heat away.
Modern cold-weather clothing is designed along similar principles to that of the Inuit. If you don’t have any such clothing, you should at least adopt the “three-layer” principle in choosing your clothing for freezing conditions. Wear a “wicking” material (such as cotton) on the inside, with a fluffy, air-trapping material like wool next to that. Over the top, wear something that will stop the wind and water from reaching the wool (such as a plastic mac), but wear it loosely, so that your perspiration has a chance to evaporate. If the inner layers of insulation get wet, whether with moisture from the outside or from the inside, all of that good work will be undone.
Drink Plenty of Liquid
Most people realise that they are likely to become dehydrated in hot weather, but few realise the dangers of dehydration in cold weather. The reason in both cases is moisture loss. In hot weather we lose it through the skin as we perspire to keep cool. In cold weather the air is very dry, and we lose moisture from our lungs every time that we breathe out. Sometimes we can even see the lost moisture as a cloud in the air in front of our face. It needs replacing – so replace it. The Inuit use snow, which they melt inside the warm body of a recently killed caribou, sucking the liquid out through a straw. My own preference is for hot tea. It doesn’t matter, so long as the drink is a warm one to keep that core temperature up.
Use Alcohol on Your Car, Not Yourself
The temptation to have a hot toddy on a freezing cold day is substantial, but it is a temptation that should be avoided if you are going to venture out in the cold. Alcohol dehydrates the body (this is one of the major effects in hangovers), so that even more water needs to be replaced.
Use the alcohol on your frozen car lock instead. Alcohol lowers the freezing point of water, and so a small splash of gin or vodka will melt the ice and free the lock.
Put Your Car to Bed
Even the Inuit now use electric block heaters to stop the engines of their snowmobiles from freezing overnight. In the absence of a block heater, your best bet is to use the engine’s own heat to protect it at the end of the day by putting an old blanket over it (and under the bonnet) so that some of the warmth will still be retained the next morning. Just don’t forget to remove the blanket before setting off!
After the sunniest year on record, Nature is hitting back with a cold snap which may see another record broken – the coldest recorded daytime temperature in England, a chilling -11.3ºC, set at Newport in Shropshire on January 11th, 1982. We may not be able to avoid the extreme cold, but by copying ancient Inuit techniques we should at least be able to cope with it.
and a final word…
Look After Your Vulnerable Neighbours
- If you believe that someone is suffering from hypothermia, the professional advice is to:
- Remove wet clothing that promotes hypothermia.
- Get to a warm place as soon as possible. Use several layers of blankets, heated in your home dryer if possible.
- If the person is alert, give warm beverages. Never give alcoholic beverages.
- Seek immediate medical attention.
(This advice is taken from http://www.princeton.edu/~oa/safety/hypocold.shtml, which also provides other excellent recommendations for hypothermic emergencies).
© This article is copyright Len Fisher. Please email Len Fisher to seek permission to reproduce part or all of the above article.