| Winter
Weather Dress: Staying Warm |
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(Page 3) Sources of Body Heat Loss In colder temperatures, your body loses heat in a number of different ways. The most frequent ways include loss through convection, evaporation, radiation and conduction. I'm sure you're thinking what in the world is this guy talking about. Simply put convective heat loss occurs when cold or cool conditions cause your body heat to be removed. Standing outside on a windy day with a temperature of forty degrees will be quite different then being outside on a forty-degree day with no wind. That's because the wind has "blown" off some of your body heat causing your body temperature to change. Layering of clothes is the best strategy to prevent convection loss. Layering causes pockets of warm air to become trapped making it harder for wind conditions to blow off and lower your body's warm temperature. Evaporative heat loss is often more difficult to control since your body continues to sweat even in cooler conditions. This often occurs if you or engaged in some form of activity or exercise. I once ran a marathon in the later part of November and remember how cold I was halfway into the race. The running clothes that I wore maintained the moisture from my perspiration causing me to be wet and cold even though I had already run twenty some miles. The best approach in these situations is to wear clothing that "breathes" or "wicks" away the perspiration from your body. There are many types of clothing designed today for the sole purpose of "shedding" this moisture away from you. The third form of temperature loss is called Radiation. Radiant heat as it's called is the type of heat you feel on your skin when exposed to an open fire. Your body acts very much like a fire generating heat from several different sources. Exercise in particular can generate increased body heat as well as the digestive activities that take place after we eat. The majority of radiant heat that we lose through our bodies escapes through our head. Therefore, prevention of this heat loss is best accomplished by wearing a hat. And finally, conductive heat loss occurs whenever something that is either cold or wet touches our body. Our body can lose heat very quickly in conditions where we are wearing wet clothing. Again, the simple remedy is to get out of those wet clothes and to wear clothing that is in layers. I once visited (as a sightseer not a felon!) the prison on Alcatraz Island off the coast of California. One of the tour guides showed us the maximum-security cells that were made of steel floors. These cells were designed specifically to rob the prisoners of their body heat causing them to sleep on their knees and elbows. This was conductive heat loss at its worst and I'm sure glad I was allowed off the island! |