Average heart rate over shift.

While working in the heat is a common practice within the Australian mining industry, it can lead to adverse effects on cognitive function, productivity, and physical health. This study aimed to compare the thermal strain experienced by maintenance workers and service workers in the mining industry during summer. Psycho-physiological parameters, manual dexterity, and cognitive function were assessed in maintenance workers (n = 12) and service workers (n = 12) employed at mine site villages in north-west Australia. Maintenance workers had the freedom to self-select their work intensity and predominantly worked outdoors (33.9±4.2°C, 38±18% RH), whereas service workers had to work to a fixed schedule and worked intermittently indoors (∼64% of work shift; 29.5±3.4°C, 48±8% RH) and outdoors (∼36%; 35.4±4.6°C, 47±21% RH). All workers underwent assessment at the beginning (day 2/3), middle (day 7/8), and end of their swing (day 13/14), at various time points throughout their 11–12 h shift. Service workers completed more steps (11282±1794 vs. 7774±2821; p<0.001), experienced a higher heart rate (p = 0.049) and reported higher ratings of perceived exertion (p<0.001), thermal discomfort (p<0.001), thermal sensation (p<0.001), and fatigue (p<0.012) compared to maintenance workers. Urinary specific gravity values were higher (less hydrated) in service workers (1.024±0.007) compared to maintenance workers (1.018±0.006; p = 0.007), with USG being overall higher post- compared to pre-shift (1.022±0.008 vs. 1.020±0.006; p<0.05). Core temperature, working memory capacity, processing speed and manual dexterity did not differ between occupations. Workers in hot environments who cannot self-select their work intensity should be educated about the importance of hydration before, during, and after their work-shifts and provided with more scheduled rest breaks during their shift. Employers should closely monitor workers for symptoms of heat illness, discomfort, and fatigue to ensure the health and safety of the workers.

高温作业在澳大利亚采矿业中颇为常见，但该作业模式可能对认知功能、生产效率与身体健康造成不良影响。本研究旨在对比夏季采矿业维修工人与服务工人所承受的热应激（thermal strain）。研究对象为澳大利亚西北部矿区村落的12名维修工人与12名服务工人，对其心理生理参数、手部灵巧度（manual dexterity）与认知功能进行了评估。维修工人可自主选择工作强度，且主要在户外作业（环境温度33.9±4.2℃，相对湿度38±18%RH）；而服务工人需遵循固定排班，作业时段约64%在室内（环境温度29.5±3.4℃，相对湿度48±8%RH），剩余约36%在户外（环境温度35.4±4.6℃，相对湿度47±21%RH）。所有工人均在各自11-12小时轮班周期内的多个时间点接受评估，评估节点覆盖整个研究轮班周期的初始（第2/3天）、中期（第7/8天）及末期（第13/14天）。与维修工人相比，服务工人轮班期间行走步数更多（11282±1794 vs. 7774±2821；p<0.001），心率更高（p=0.049），且自我报告的自觉劳累程度（perceived exertion）、热不适程度、热感觉及疲劳感评分均更高（p分别<0.001、<0.001、<0.001及<0.012）。服务工人的尿比重（urinary specific gravity, USG）为1.024±0.007，高于维修工人的1.018±0.006（p=0.007）；且无论何工种，工人轮班后的尿比重均显著高于轮班前（1.022±0.008 vs. 1.020±0.006；p<0.05）。两类工人的核心体温、工作记忆容量、处理速度及手部灵巧度均无显著差异。对于无法自主选择工作强度的高温环境作业工人，应向其宣教轮班前、中、后补水的重要性，并在轮班期间安排更多计划性休息时段。雇主应密切监测工人的热相关疾病、不适及疲劳症状，以保障工人的健康与安全。