Saturday, March 21, 2009

A Chilling Account

I should probably wait and post this at the beginning of Winter but in some ways it's an even better read now that Spring is upon us.

A few choice excerpts from a well written article on Outside Online about what it's like to experience hypothermia...
  • Were you a Norwegian fisherman or Inuit hunter, both of whom frequently work gloveless in the cold, your chilled hands would open their surface capillaries periodically to allow surges of warm blood to pass into them and maintain their flexibility. This phenomenon, known as the hunter's response, can elevate a 35-degree skin temperature to 50 degrees within seven or eight minutes. Other human adaptations to the cold are more mysterious. Tibetan Buddhist monks can raise the skin temperature of their hands and feet by 15 degrees through meditation. Australian aborigines, who once slept on the ground, unclothed, on near-freezing nights, would slip into a light hypothermic state, suppressing shivering until the rising sun rewarmed them.
  • As you sink back into the snow, shaken, your heat begins to drain away at an alarming rate, your head alone accounting for 50 percent of the loss.
  • In the minus-35-degree air, your core temperature falls about one degree every 30 to 40 minutes, your body heat leaching out into the soft, enveloping snow. Apathy at 91 degrees. Stupor at 90.
  • By the time your core temperature has fallen to 88 degrees, your body has abandoned the urge to warm itself by shivering. Your blood is thickening like crankcase oil in a cold engine.
  • At 85 degrees, those freezing to death, in a strange, anguished paroxysm, often rip off their clothes. This phenomenon, known as paradoxical undressing, is common enough that urban hypothermia victims are sometimes initially diagnosed as victims of sexual assault. Though researchers are uncertain of the cause, the most logical explanation is that shortly before loss of consciousness, the constricted blood vessels near the body's surface suddenly dilate and produce a sensation of extreme heat against the skin.
  • In fact, many hypothermia victims die each year in the process of being rescued. In "rewarming shock," the constricted capillaries reopen almost all at once, causing a sudden drop in blood pressure. The slightest movement can send a victim's heart muscle into wild spasms of ventricular fibrillation. In 1980, 16 shipwrecked Danish fishermen were hauled to safety after an hour and a half in the frigid North Sea. They then walked across the deck of the rescue ship, stepped below for a hot drink, and dropped dead, all 16 of them.

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