Big chunks of the eastern and central United States lie blanketed in a mass of Canadian Arctic air that has driven temperatures way below freezing and caused the deaths of at least four people in the Midwest. Experts say that cold can kill, even in moderate weather, and is especially lethal for the elderly, young children or people compromised by alcohol or drugs. While the human body does a pretty good job keeping itself warm, prolonged cold can lead to hypothermia, which occurs when the body's core temperature drops below 95 F.
When the body loses more heat than it can generate, things go wrong. In fact, one of the first things to go haywire is judgment. In the first stages of hypothermia, victims may lose the ability to think or move - both are necessary for survival outdoors - and may not even know they need help. Frostbite to the fingers and toes follows as the body shunts warm blood from the extremities to the core to protect its organs.
Symptoms of hypothermia include drowsiness, confusion, weakness ("I think I'll sit down here and rest a minute") as well as pale skin and uncontrolled shivering, according to the National Institutes of Health. If you don't get treatment, your body slows, heart rate diminishes and it isn't long before your entire body shuts down and eventually goes into cardiac arrest. The good news is that hypothermia is preventable with proper clothing (non-cotton layers, hat and gloves) and staying inside during extreme weather.
PHOTOS: On Earth's Cold Edge
Experts say booze and cold weather don't mix. Drinking can actually speed hypotheria because it takes blood away from the organs and sends it to the skin. That cools the heart, brain and internal organs even quicker. Smoking also interferes with circulation. For more tips on what not to do, check out Jack London's harrowing 1908 short story "To Build a Fire" about a Yukon traveler lost in the snowy wilderness.
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