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January 2012 How To Survive!

Posted in Features on January 1, 2012
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Plenty of time is spent every season talking about winterizing a vehicle, but what about winterizing you? After all, blackened limbs from frostbite, hypothermia, freezing one’s arse off—those aren’t really issues a Jeep has to worry about. This month, we spoke with Douglas Freer, M.D., D.P.M., M.P.H. and medical director of Raytheon Polar Services/the U.S. Antarctic Program of the National Science Foundation, for the lowdown on how to survive all things cold. Because: Antarctica. The guy knows cold.

• First off, Doc, why do we get cold? “Body temperature is a balance of heat production and heat loss. Heat production is by cellular metabolism, while heat loss is primarily via the lungs and skin by the process of evaporation, radiation, conduction, and convection.” This is going to be on the test, isn’t it? Dr. Freer added that exposure to cold triggers a reflex constriction of skin blood vessels and sends a signal by way of the nervous system to produce and conserve heat, which translates into such gems as shivering, increased heart rate, hormonal changes (no, not hair suddenly on your chest), and even behavior responses, like when you put on a jacket or head indoors.

• We’re betting there’s a body part that’s a troublemaker and loses heat most quickly and it’s—skin! “This ability to dilate in heat and constrict in cold is most profound in the fingers, toes, and nose.” But how much trouble you can get into depends on not only the type of cold, humidity, altitude, and exposed tissue, but how long you’re exposed to it. And an even bigger issue is the wind chill index. What are you trying to avoid here? Hypothermia.

• More for the test: “Hypothermia is a central body or core temperature below 95 degrees Fahrenheit. Although most often associated with cold environments, it can occur in almost any climate.” There are two types, actually: primary and secondary. Primary is also known as accidental or environmental, while secondary refers to some underlying medical condition that predisposes you to the development of hypothermia (like trauma, medications, or hypoglycemia). Severity of hypothermia is defined by the core body temp, which is broken down as mild, moderate, and severe. Or in layman’s terms, rut-roh, oh boy, and poo-hitting-fan.

• For mild/rut-roh hypothermia, your breath rate might increase and you may shiver, slur your speech, and have impaired judgment. “The classic description is the ‘stumbles, mumbles, and grumbles’ with intense shivering,” explained Dr. Freer. With moderate/oh boy, things go the other way, by slowing down—decreased breathing rates, lack of reflexes, and an abnormal heart rhythm. With severe/poo-hitting-fan, you are comatose, have no reflexes, and do not respond to painful stimuli. “The lowest recorded survival from environmental hypothermia in an adult is 60.8 degrees Fahrenheit.”

• So, what now? It may seem obvious, but you want to stop the heat loss. No matter what level of hypothermia, try to get the person into shelter. Also, “There’s a myth that you take someone who is cold and wet and remove all their clothing and throw them into a warm sleeping bag and then put a seminude person in with them, thinking this will warm them up. All of us have had fantastic fantasies.” Well, we’re warm now. Go on: “But the more recent data is that for people who are mildly hypothermic, their best physiologic response is to create heat from shivering, and the second body may inhibit the shivering response; when you put a warm body next to a cold body, they sort of come to the same temperature and you end up with two people who are cooler than they should be instead of warming up the cold one.” So if someone isn’t in the moderate/severe state, it’s better to skip the secondary body and instead make him drink warm, sugar-containing fluids. For the latter two categories, you’ll want to try and prevent further heat loss and handle the person gently to avoid cardiac dysrhythmia. The rewarming should really be done at the hospital because of complications that could take place, so make getting there the priority.

• Another thing: “All exposed individuals become dehydrated. When you’re exposed to a cold environment, the blood vessels in your arms, legs, and other exposed areas constrict and reduce blood flow to the extremities in order to conserve heat. The constriction redistributes this blood back into the central circulation.” Your body in turn thinks it’s a sort of volume overload to the central core and starts reacting, such as “you start peeing like a bandit.” (That’s called cold diuresis, for the test.) “Even if you’re dehydrated out in the desert or even in the office, your kidneys sense that and they will try to retain fluid so you don’t urinate as frequently. But that doesn’t seem to happen in cold, so you’re still peeing like crazy.” You also lose water by way of evaporation from breathing and exertion; trying to winch/shovel out a stuck Jeep will cause you to sweat, so there will be fluid loss.

• Don’t eat snow to rehydrate. “The ice will actually draw fluid out of your tissues. It’s better to defrost it,” Dr. Freer said. A tip he shared: To melt ice quicker, fill your open container with snow, put a rock on it, and set it in the sun; it will melt faster with that pressure from the heating rock. To prevent your bottle of water from freezing at night, put it in your sleeping bag with you. And if it is partly frozen, moving water is warmer than letting the bottle just sit there, so you can put it in a stream. You know, if you don’t have a stove or campfire.

• What about when you’re cold while doing nothing, like in your sleeping bag? If your feet are cold, put a cap on, because you can lose as much as 70 percent of your body heat through exposed areas like your head.

• But technically wasn’t all the above a bit of a spoiler alert? How can you avoid getting to the point of hyperthermia? Let’s start with clothing. A commonly recognized acronym is COLD: keep clothing clean, avoid overheating, wear loose clothing/layers, and keep clothing dry. Loose clothing will help trap air near the body; your goal is to create a sort of microclimate next to the skin to allow for warm-air trapping and wicking. And wicking fabrics that are dirty or oily begin to lose their capabilities.

• If you’re stuck in the cold, staying in Motel Jeep will protect you from the elements, and the seat will be a lot more comfortable than the ground. But if you must resort to outdoor shelter, a debris hut is the simplest to build, so use things like fallen timber. Look for where there is protection by trees. If there’s snow and you’ve spotted a slope, you might be able to build a snow cave. Keep in mind the possibility and likelihood of an avalanche where you’re eyeballing shelter, and avoid setting up under tree branches encrusted with snow, because when that falls off, it’ll leave a mark. Natural caves are good for shelter, as are hollow trees, but check for vermin and insects. Now, if you’re in, oh, Antarctica, where there are no trees and a flat plateau, “You have only two things you can do: Dig down to make a snow cave or mound snow over a bunch of gear, then pull out the gear for what is known as a quincy shelter,” said Dr. Freer. For the record, igloos “are a bitch to build.”

• To warm yourself by fire, there are a few tricks courtesy of Dr. Freer. Carry cotton balls, which will spark quickly when they meet gasoline and match or flint stick. “Another thing that works well is very fine steel wool. And unlike if a cotton ball gets wet, you can remove the moisture. Lint from the dryer is another good fire-starter, but only if you have lint from cotton clothes. Lint from synthetic and nylon stuff doesn’t spark very well.” And use a soft wood, like pine or spruces, or “squaw wood”—wood that’s already on the ground and is old and dried out. Denser woods such as oak or manzanita will take forever to burn, and also avoid wet, green, fresh wood, because it will smoke like crazy.

• If you must venture out in the snow on foot, insulation is key. Consider this if things are bad: “Take foam from the seat cushion and duct tape it around your shoe for a cheap Mukluk boot to help keep your feet dry. You can also stuff it in your clothing, especially around your body core.”

Sources

United States Antarctic Program
http://www.usap.gov

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