Tackling Cold Stress

Accidental hypothermia in human subjects can occur almost anywhere in the world, even in those areas with the hottest climates, for example, because of industrial accidents. However, on a day-to-day basis the potential risk of being subjected to accidental hypothermia is greatest for those living and working at high latitudes, with cold water immersion representing the most extreme challenge. Although most of the effort concerned with protection against cold exposure has involved finding ways of decreasing heat loss by improving insulation, some attempts have been made at finding ways of improving cold tolerance by modifying the thermoregulatory response to cold. The main strategies that have been used are thermal acclimation, physical exercise, dietary enhancement of thermogenesis, pharmacological enhancement of thermogenesis, and manipulation of thermoregulatory set point. This chapter briefly reviews the success of these strategies. Although none of the strategies examined has resulted in concrete methods that are routinely used to improve cold tolerance, it is concluded that the pharmacological enhancement of cold thermogenesis using ephedrine in combination with methylxanthine represents the most promising method for delaying the onset of hypothermia in humans.