LeBlanc J
Department of Physiology, Faculty of Medicine, Laval University, Quebec City, Canada.
Int J Sports Med. 1992 Oct;13 Suppl 1:S169-72. doi: 10.1055/s-2007-1024629.
The animal model used the most frequently for understanding the mechanisms of adaptation to cold in humans has been the rat. It has been established that rats kept in the cold for a few weeks stop shivering while preserving a normal internal temperature because of an enhanced thermogenic capacity of the brown adipose tissue (BAT) mediated by the sympathetic nervous system. Studies on groups of humans exposed to cold have shown that shivering is also attenuated but without compensatory increased in heat production possibly because of non-significant contribution of the BAT. However when humans and laboratory animals are exposed repeatedly to short severe cold evidence for adaptation has been described. This adaptation is not metabolic; instead it is related to the phenomenon of habituation. When exposed to a novel stress such as cold, the alarm reaction is initiated as evidenced by the activation of the sympathetic nervous system which opposes the stressing situation. However with time, when it is realized that the normal functioning of the body is not endangered the responses are attenuated and enhanced tolerance is observed. This type of adaptation was observed in Eskimos, fishermen, outdoor workers, etc.
在用于理解人类对寒冷适应机制的动物模型中，使用最为频繁的是大鼠。已经证实，将大鼠置于寒冷环境中数周后，它们会停止颤抖，同时由于交感神经系统介导的棕色脂肪组织（BAT）产热能力增强，体温仍能保持正常。对暴露于寒冷环境中的人类群体的研究表明，颤抖也会减弱，但产热可能不会有代偿性增加，这可能是因为BAT的贡献不显著。然而，当人类和实验动物反复暴露于短暂的严寒时，已有适应的证据被描述。这种适应不是代谢性的；相反，它与习惯化现象有关。当暴露于诸如寒冷这样的新应激时，交感神经系统的激活会引发警觉反应，以对抗应激情况。然而，随着时间的推移，当人们意识到身体的正常功能没有受到威胁时，反应就会减弱，耐受性也会增强。这种适应类型在爱斯基摩人、渔民、户外工作者等人群中都有观察到。
