Studies on changes in human heat adaptability in an era of global warming and widespread use of artificial environments

为了更好地理解热带原住民的热习服现象，我们比较了热带原住民和温带原住民在休息、被动和主动加热条件下的种族差异。实验方案包括：(1)休息条件(空气温度为28℃，相对湿度为50%)；(2)被动加热条件(28℃，相对湿度为50%；腿部浸泡在水温为42℃的热水浴缸中)；(3)主动加热条件(32℃，相对湿度为70%；自行车运动)。形态和身体上匹配的热带原住民(10名马来西亚男子，我的)和温带原住民(10名日本男子，JP)参加了所有三个试验。结果表明：与温带人相比，热带人安静时的直肠温度较高，安静时的手脚温度较低，直肠温度升高较小，四肢温升较大，被动和主动加热时的口渴感觉较低，提示热带人加热时体内温度的稳定性提高，肢体血管循环能力增强，口渴程度较低，从而有效地控制了采暖期间的体内平衡。

For the coherent understanding of heat acclimatization in tropical natives, we compared ethnic differences between tropical and temperate natives during resting, passive and active heating conditions. Experimental protocols included: (1) a resting condition (an air temperature of 28℃ with 50% RH), (2) a passive heating condition (28℃ with 50% RH; leg immersion in a hot tub at a water temperature of 42℃), and (3) an active heating condition (32℃ with 70% RH; a bicycle exercise). Morphologically and physically matched tropical natives (ten Malaysian males, MY) and temperate natives (ten Japanese males, JP) participated in all three trials. The results saw that: tropical natives had a higher resting rectal temperature and lower hand and foot temperatures at rest, smaller rise of rectal temperature and greater temperature rise in bodily extremities, and a lower sensation of thirst during passive and active heating than the matched temperate natives.It is suggested that tropical natives’ homeostasis during heating is effectively controlled with the improved stability in internal body temperature and the increased capability of vascular circulation in extremities, with a lower thirst sensation.