On winter days, during a stay outdoors, cold feet are often the reason to return to the heated space and stop winter adventures. The reasons for this phenomenon are related to the physiology of the feet as well as to the shoes and socks that are on the feet. Geographically speaking, the feet are the Antarctica of the human body, very far from the source of heat — the heart, that is, the entire chest and abdominal cavity. The feet have about 250,000 sweat glands, per unit area more than any part of the body (the soles about 600, and the upper part of the foot about 250 glands per cm2). Feet can produce up to half a glass of sweat per day. The glands constantly produce sweat, not only during high temperatures or physical exercise. Most footwear acts as a moisture barrier, preventing evaporation and drying of socks. Considering that water is a much better conductor of heat than air — even 25 times, the heat from the feet will be lost much faster in such conditions.
As Paul S. Auerbach claims in the book Auerbach’s Wilderness Medicine;
“Nonfreezing cold-induced injuries were observed more frequently when the temperature hovered around the freezing point — when the ground was
muddy rather than frozen. Standing or sitting for a long period, wearing constrictive footwear, malnutrition, fatigue, or the blunt trauma of marching on cold, wet feet all added to the severity of the injury.”
