Predictions of Human Tolerance in Cold Environments
As was previously mentioned, attempts have been made to model human thermoregulatory responses in cold environments and to arrive at times for various stages of hypother to begin. The complex interaction of various environmental clothing, and physiological factors allows for the generation of such cooling curves to be extremely conservative. The physiology of the hypothermic individual varies with the degree of core cooling, which does not permit simplistic modeling. For example, individuals whose core temperature falls at a rate of 1.5°C per hour and who breathe 4% carbon dioxide lose core temperature faster than controls. However, if the rate of cooling is three Centigrade degrees per hour, the effect of carbon dioxide is not noticed. The use of various agents (eg, herbs, drugs) has not been extensively studied for effectiveness in enhancing metabolic rate or resistance to cold stress. Nevertheless, in military communities such agents are routinely rumored to be effective but without a shred of scientific data.