The feet are one of the most important places on the body to keep warm, and one of the most challenging! But if you know the difficulties in advance, you can avoid troubles before they arise, both on winter hiking trips and in an emergency.
Threats
The body loses heat in five ways: respiration, evaporation, conduction, convection and radiation. Different precautions are necessary to stop each of these heat-stealers.
- Perspiration: Heat loss by evaporation is caused by perspiration. To prevent it, wear layers.
- Conduction: Conduction occurs when the body is close to a cold, wet object. Stop it with insulation.
- Convection: To avert loss by convection, keep your feet and other body parts out of the wind.
- Radiation: Heat loss by radiation is a killer. Prevent it by keeping your body covered, especially your head, hands and feet.
- Respiration: To prevent heat loss by respiration, cover your mouth and nose with a warm, but breathable fabric.
Play close attention to all of these except respiration to safeguard your feet. Maintaining warm feet is particularly challenging because body weight squeezes air out of socks and other insulating material under the feet. Also, the movement of the feet while walking prevents air from remaining still around feet and warming from body temperature. Perspiration causes moisture to collect inside boots, sometimes in the form of frost.
Precautions
One way to protect your feet is with insoles. They can help stop heat loss by both convection and perspiration by preventing cold from coming up from the ground and turning perspiration into frost. Alternate between two pairs of insoles to insure that one pair is always dry.
Also, wear layers of medium weight socks instead of one pair of thick socks. With layers, moisture is isolated, and the air in between the socks provides extra warmth. When wearing multiple pairs of socks keep the thickest sock to the outside to avoid foot cramps and restricted circulation. Change damp socks frequently.
And cover your head! A large amount of body heat is lost out of the head so a hat will raise the temperature of your whole body, including your feet.