From: Andy Soos, ENN
Published January 8, 2010 10:24 AM

How Cold Is It?

It is very cold in most of the US this winter. It brings to mind is it so cold that you can freeze to death as well as what happened to global warming? Cooling as well as warming trends have happened before and will happen again. Back in the 1970's for example winters turned significantly colder for awhile.


Meteorologists are quick to point out that reliable U.S. weather data goes back only to the late 1800s, so it's normal for records of various types to be broken every year, somewhere, when dealing with such a relatively brief data set. Any given day or year may set set a record.  For global warming it is the long term trend that is important.

When cold air hits your body, blood will move away from your skin, fingers and toes and towards the inner core.  This process is called vasoconstriction, and it helps limit the amount of heat you lose to the environment.  The opposite effect is called vascodilation where blood goes to the skin and heat is lost to the cold air (though you feel warm).  This is what happens when one drinks too much alcohol.

Shivering also occurs when you get cold.  Major shivering also occurs when your body core temperature drops very low.  This is called hypothermia.  This normally will not happen excedt under severe and prolonged exposure.

If you're wet and cold, your body loses heat up to 25 times faster.  So being in wet clothing may cause more damage than just being in cold weather.  Even sweat may do this. 

The wind will also cool a person.  In summer it a a cool refreshing breeze.  In winter it is called wind chill.

Normal core body temperature is 98.6 degrees Fahrenheit (F). Mild hypothermia sets in at about 95 degrees F. Below 70 degrees F, you are said to have profound hypothermia and death can occur.  A person in hypothermia may be unconscious and may appear dopey or intoxicated.

The record for the lowest body temperature at which an adult has been known to survive is 56.7 degrees F, which occurred after the person was submersed in cold, icy water, according to Castellani of the U.S. Army Research Institute of Environmental Medicine.

Frostbite, an injury caused by freezing, is more common in everyday scenarios.  This is because fingers and toes are more easily isolated from the body higher temperatures.Since frostbite is brought on by freezing, you can't get frostbite if the air temperature is above 32 degrees F. "It takes a wind chill temperature of around minus 15 degrees [F] where you start to see an increase in the incident of frostbite," Castellani said.

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