when it’s too cold

Monday, December 9, 2013

It’s expected that the frozen tundra that is Lambeau Field would host cold weather NFL games in the middle of December, but that scenario was also true in Philadelphia, Denver, Pittsburgh and Chicago where snow, ice and single temperatures welcomed not only the players but tens of thousands of fans. The decision to play in frigid weather might be a variant of “the show must go on”, but for fans to choose the cold of an outdoor stadium, instead of watching the game on television in a warm house seems somewhat questionable.  Is hypothermia and frostbite worth the collective game experience?

The body functions quite poorly as it chills, and for that reason, there are a variety of mechanisms built in to maintain body heat. Normally, body temperature is regulated by the hypothalamus in the brain and heat is generated by cell metabolism, mostly in the liver and heart. When the body starts to chill, the brain tells the body to ramp up heat production by muscle shivering (up to 5 times more than baseline). But in cold environments, shivering may not be enough to keep the body warm. It take significant energy for all that muscle work and glycogen stores within muscle cells can be depleted, a process no different than running out of energy after exercising. The brain can put the body into survival mode and starts to shunt blood from the skin, where it can be cooled by exposure to the cold environment, and pushes is toward the body’s core, trying to keep vital organs like the heart, lung, intestines and brain warm.

Unfortunately, the shunting of blood away from the skin, especially to the far reaches of the body in the fingers, toes, nose and ears, increases the potential that frostbite will occur. Ice crystals can form in the interstitial spaces between cells. Cell damage can occur either from these ice crystals, directly from the cold and from sludging of blood in the small blood vessels. When skin temperature drops to 60F, blood flow drops to 10% of normal. When it gets to freezing (32F), blood flow stops. In between, blood occasionally pulses to try to maintain some semblance of circulation but may or may not be successful.

For those who have lived in a northern climate, the symptoms of frostbite are well recognized; cold, stinging and throbbing is followed by intense pain when the area is rewarmed. With increasing severity of frostbite, there is numbness followed by complete loss of sensation and difficulty with dexterity and function. Frostbite is classified similarly to thermal burns depending the appearance of the skin and it may take time to appreciate the amount and depth of frostbite injury. White skin with surrounding redness signals a first degree injury. Over time, if skin starts to blister, it may be a sign of deeper second degree injury. Third degree frostbite may take a couple of weeks to become apparent with full thickness skin injury and gangrene formation.

While frostbite is not good, hypothermia is even worse. As the body loses its ability to compensate for the increased heat loss in a cold environment, organs begin to slow down. Electrical activity also is affected and victims can become lethargic and confused. Interestingly, patients develop paradoxical undressing, where clothes are shed even in the coldest weather.  Heart electrical conduction can be affected and as the body cools, the regular rate and rhythm may degenerate into unstable patterns like ventricular fibrillation that cannot sustain life.

The body is able to adapt to the cold but not as well as it can adapt to heat. Fortunately by wearing layers of clothes, staying active and keeping dry, heat loss can be minimized. Unfortunately, alcohol and drugs can affected the body’s ability to conserve heat. Most often, the best treatment for preventing hypothermia and frostbite is prevention. The players had reason for being outside in the bitter cold doing their job, but we can only presume that the fans were in the stands because of their love for the game, not for the sanity of their decision.

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