in the depths of winter, insulating yourself against the cold temperatures sometimes takes a little more than a thick coat and warm shoes. especially in extreme temperaturesif your mother ever told you that you should wear a hat because you lose half your body heat through your head, she wasn’t alone in that belief. in fact,
according to live science, the u.s. army also subscribed to this, claiming that we lose 40 to 45 per cent of body heat through our head. except that it’s not true.a
2008 study investigating various medical myths found that heat loss is relatively proportional to the skin that is exposed. since the head accounts for about seven per cent of the body’s surface area, it stands to reason that a person only loses seven to 10 per cent of their body heat through the head.researchers arrived at that conclusion by submerging subjects wearing only swim trunks in water, and measuring the heat loss throughout the body.but the seven to 10 per cent heat loss from the head only applies when the entire body is exposed to the elements — so when we’re outside in the winter with our parka and boots on, an exposed head would be the primary source of heat loss, much higher than seven to 10 per cent. covering your head with a hood or hat is an easy way to conserve your body heat and stay warmer.staying warm can be a challenge in extreme cold, but it’s important to reduce your exposure to the elements.according to the
government of canada, 37ºc (99ºf) is normal body temperature, but when your core body temperature drops by 1 or 2ºc (1.8 or 3.6ºf), or your body is exposed to severe cold, there could be harmful effects on your health.
when the body is exposed to extreme cold
once exposed to extreme cold, the body starts to go into self-preservation mode and the blood vessels close to the surface of the skin start to narrow to protect the core temperature. over a long period of time, the blood flow to the body’s extremities (hands, feet, nose, ears) can be extremely limited, causing frostbite.the early stage of frostbite, called frostnip, is treatable by warming the area and there are no lasting effects.
frostbite begins with cold skin that eventually goes numb. it can then turn red, white, blueish-white, grayish-yellow, purple or brown depending on the person’s skin colour and how severe the frostbite is. the skin can also appear hard or waxy.
severe frostbite needs medical attention as there can be permanent damage to the skin, muscle, and other tissue.when exposed to extreme cold, the body can also develop hypothermia — losing heat faster than it can produce it. this causes the body’s internal temperature to drop to dangerously low levels and happens in
three different stages.shivering, goosebumps. in stage one, the body’s internal temperature drops by one or two degrees, and causes shivering, goosebumps on the skin and numbness in the hands.
harder to move, blue skin. stage two starts with a warm sensation as the body’s temperature drops between two to four degrees. at this point, it becomes much harder to move and extremities may start to turn blue. there may also be some mild confusion and paleness.
difficulty thinking and walking. in stage three of hypothermia, your body temperature drops below 32 degrees and doing simple things such as walking, talking, or even thinking become difficult. any exposed skin will turn blue, your pulse will decrease, and it will become hard to move. there is also an extreme risk of dying at this stage of hypothermia.stage two or three of hypothermia, is an emergency — call 9-1-1 immediately. stage one can be treated by gradually warming the body, finding shelter and drinking warm liquids.
nick beare is a toronto-based freelance writer.
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