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.