Work Physiological Study on Thermal Loads Caused by Body cooling during Intermittent and Repeated cold exposure

本研究的目的是阐明在日常冷工作中观察到的间歇性和反复冷暴露引起的冷防御反应特征和相关的热负荷。为此，我们在人工气候室内进行了实验研究，并在一些寒冷的工作场所进行了调查。主要研究结果如下：1。间断性手指降温实验表明，冷痛、冷感觉等主观判断并不总是监测外周过度降温和冻伤形成风险的可靠和敏感指标。全身冷暴露实验发现，重复的冷暴露，即使加上温暖的休息，也会引起身体核心的连续冷却，心血管负荷增加，体力下降。热休息时的主观热舒适和热感觉不是监测低温状态和热负荷增加的可靠指标。这种现象可以用皮肤表面温度和身体核心温度在产生热调节效应反应时的倍增相互作用来解释。通过对冷库行业、冬季户外作业和食品行业的实地调查发现，许多工人在不自觉的情况下，存在外围部分和全身过度降温的现象。调查结果支持了我们的上述实验发现，也表明工人根据自己的判断选择的防寒服的保温性不足以满足他们的冷作业。这些结果表明，在冷作业中，根据工人的主观判断来规划作息和使用冷防护装备，容易使工人在不自觉的情况下过度散热和增加热负荷。为了预防这些健康风险，我们需要建立合理的冷作业管理制度。作为我们实现这一目标的方法之一，我们计划标准化评估CPE热防护性能的测试方法，并根据测试结果提出冷暴露极限。少

The purpose of this research was to elucidate the characteristics of cold defense response and associated thermal loads caused by such intermittent and repeated cold exposure as observed in daily cold work. To achieve this, we carried out both the experimental studies in an artificial climatic chamber and the surveys in some cold work places.The main results obtained were as follows :1. The intermittent finger cooling experiment revealed that subjective judgment such as cold pain and cold sensation is not always a reliable and sensitive index for monitoring the risk of excessive peripheral cooling and frostbite formation.2. The whole body cold exposure experiment found that repeated cold exposure, even interposed with warm rest, caused successive body core cooling, increased cardiovascular load and decreased manual performance. The subjective thermal comfort and warm sensation at each warm rest were found to be not reliable indices for monitoring hypothermic state and increased thermal … More loads at the time. This phenomenon could be explained by a multiplicative interaction between skin surface and body core temperatures in the generation of thermoregulatory effector responses.3. The field surveys in refrigerated warehouse industry, outdoor work in winter and food industry found that many workers had excessive cooling of the peripheral part and whole body without noticing them. The surveys supported our experimental finding mentioned above and also showed that thermal insulation of cold protective clothing the workers chose by their self-judgment was insufficient for their cold work.4. These results suggested that planning work-rest schedule and using cold protective equipment (CPE) at cold work based on workers' subjective judgment are liable to cause them excessive body cooling and increased thermal loads without noticing.5. To prevent these health risks, we need to establish a rational management system for cold work. As one of our approaches for achieving this, we plan to standardize a test method for evaluating thermal protective performance of CPE and to propose a cold exposure limit based on the test results. Less