The weather outside is frightful…

Tuesday, December 23, 2008

It’s game time at Soldier’s Field in Chicago as the Bears host the Packers for Monday Night Football. The players are greeted with frigid temperatures as they run onto the field. It’s barely above zero with a light wind from the southwest and a calculated wind-chill is 10 below, but the Chicago players are oblivious to cold as their bare arms are exposed to the cold. They must be oblivious because a rational person would dress for the bitter cold.

As winter storms hit much of the country, it’s important to remember that cold kills. Hypothermia or low body temperature affects how the body works, decreasing function and causing all sorts of physiologic breakdowns. The brain function slows and affects judgment. The heart muscle can become irritable as the electrical conduction system fails and skin loses its ability to shield the body form the environment. Actually, the body sacrifices the skin and pother organs to protect the vital core organs that it needs for survival: heart, lung, kidney and brain.

The body responds to cold by constricting arteries in the areas that are cold, shunting blood away from the skin to preserve heat. Shivering is turned on to generate heat but shivering is a short term fix. If cold exposure continues beyond the ability of the body to compensate, damage can occur. Ice crystals can form in the spaces between the cells damaging the integrity of cell walls and they can leak fluid and chemicals that make the process worse. Attempts by the body to restore blood flow can fail if the blood vessels themselves have been damaged by the cold and are unable to dilate and allow blood to return to the affected area. It’s usually the end of the line for blood flow that can be damaged including fingers, toes, cheeks, ears and noses. But any exposed skin area is at risk.

Wind-chill measures how cold air feels on human skin. It’s a combination of temperature and wind without sunshine and is a measure the frostbite threshold value, how long skin can be exposed until frostbite will occur. It would have taken 30 minutes for one of the Bear players to develop frostbite on that cold night in Chicago.

Frostbite can be classified by degree like a burn. Frostnip or first degree frostbite is like a sun burn. The skin turns red, make swell and there is a fair amount of pain especially with rewarming. Second degree frostbite causes deeper skin damage with blistering and numbness. Third degree frostbite affects the full thickness of the skin. It can present with bloody blisters leading to skin death and because it affects the layer of skin that contains nerves and blood vessels, there is often little pain, aching or sensation. Forth degree frostbite affects not only skin, but freezes underlying muscle and bone.

Like many injuries, frostbite is preventable by good planning. Dressing for conditions in layered clothing and wearing a hat may be all that is needed. Cold and water are a bad combination since clothes and skin both lose their insulating properties when they get wet. Cold and wind also don’t go so well together.

Avoiding the cold may not be an option for the many people who have to live in a northern climate and there are many who enjoy winter sports and being outdoors. But a pro football player probably should know better than to pit bare skin against the elements. And while we often ask that athletes act as role models, perhaps this is one time when their actions should be ignored.

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