PUBLISHED 01/09/2004
Freezing Conditions
When the mercury sinks below 32, do you immediately pull on your parka? Not so fast. The first rule of cold-weather running is to dress "comfortably cool," says Kate O'Brien, a researcher with the Thermal and Mountain Medicine Division of the U.S. Army's Research Institute of Environmental Medicine in Natick, Massachusetts. Once you start running, your core temperature will rise and stay elevated. Wear too much, and you'll overheat. If you're warm once you're out the door, shed a layer before you start running.
Which brings us to the second rule: layering. Start with a thin, breathable base layer, which pulls, or wicks, moisture away from your body. If the temperature is above freezing and the wind is calm, a base layer may be enough to keep you warm. Below freezing, add a mid-layer of lightweight fleece to keep the moisture moving away from your skin as well as to provide insulation. Your last layer is a shell, which protects you from wind but still allows moisture to escape your layering system. Today's tightly woven soft shells are made of high-tech fabrics--such as the stretch nylon of the Isis Sophia jacket and the "interface Bw fabric" of the Helly Hansen Rapide jacket--that breathe almost as well as your base layer. The other advantage of layers is you can ditch one or more if you've ignored rule No. 1 and gone out overdressed. Still not sure how much to wear? Check out our What Should I Wear? tool.
