SATURDAY, March 1, 2003 (HealthDayNews) -- Anyone who's been outside on a windy, winter day knows it's a lot more difficult to stay warm than on a calm day with the same temperature.
That's because of the wind chill, a combined effect of low temperature and wind, says an Environment Canada fact sheet.
On a calm winter day, our bodies warm up a thin layer of air close to our skin -- called the boundary layer -- and that helps to insulate us from the cold air. However, when the wind starts to blow, it strips away this boundary layer and our skin is more exposed to the cold air.
Our bodies try to warm up a new boundary layer, but it keeps getting blown away by the wind. Our skin temperature starts to drop, and we start to feel colder.
There's another way that wind can make you feel colder. It evaporates any moisture that's on your skin and that draws more heat away from your body. Research shows that when your skin is wet, it loses heat much faster than when your skin is dry.
Because wind chill speeds up the rate at which your body loses heat, it can be dangerous. Each year in Canada, more than 80 people die from overexposure to the cold.
You can guard against wind chill by wearing clothing with high insulation properties to trap air and create a thicker boundary layer around your body. Change out of wet clothing or footwear as soon as possible because it loses its insulation value and results in body heat loss almost equal to that of exposed skin.
Even your body type is a factor in how you're affected by wind chill. Tall, slim people get colder faster than shorter, heavier people. Age and physical condition also influence your susceptibility. Older people and children have less muscle mass and therefore generate less body heat.
If you do start to get cold, you can generate more warmth through physical activity such as walking. Even soaking in the sun can make you feel much warmer. Taking shelter from the wind is another way to reduce the effects of wind chill.
Pay attention to wind chill warnings and avoid going outside when the wind chill factor is severe.
More information
The U.S. National Weather Service has more information about wind chill, including a wind chill chart.
