James R, Dukes-Dobos F, Smith R
Am Ind Hyg Assoc J. 1984 Jun;45(6):399-404. doi: 10.1080/15298668491400016.
Physiological responses and perceived strain of five unacclimatized male subjects were studied. The subjects were exposed to heat during an exercise task and were evaluated while wearing half and full facepiece, cartridge-type, air-purifying respirators, and without a respirator. The exercise consisted of walking on a treadmill for a period of 1 hour in a controlled environmental chamber at each of two different energy expenditure levels (200 and 400 Kcal/hr) (approximately equal to 58 and 116 Watts) and two different heat exposures (air temperatures of 25 degrees C and 43.3 degrees C). The results indicated that wearing a full facepiece respirator imposed significant physiological strain added to that caused by the heat and workloads used in the study. Five of the six physiological measures show this increased physiological strain: heart rate; minute ventilation; oxygen consumption; energy expenditure; and oral temperature. There was no detectable effect on sweat rate. Although subjective ratings indicated more discomfort with increasing physiological strain, the observed correlations between such measures were low (Tb less than .60). The net consequence of the significant effects indicates that workers' tolerance to moderate or higher levels of work under hot conditions while wearing a respirator is reduced. The reduction is more pronounced when wearing a full mask than when wearing a half mask. Changes in respirator design which minimize respiratory dead space are suggested to alleviate this problem. Otherwise, prevention of excessive physiological strain from respirator use when working at moderate or higher levels at hot job sites could necessitate more rest breaks or limiting work time under such conditions.
对五名未适应环境的男性受试者的生理反应和感知到的压力进行了研究。受试者在一项运动任务中暴露于高温环境下，并在佩戴半面罩和全面罩、滤毒罐式空气净化呼吸器以及不佩戴呼吸器的情况下接受评估。运动包括在控制环境舱内的跑步机上行走1小时，在两种不同的能量消耗水平（200和400千卡/小时）（约等于58和116瓦）以及两种不同的热暴露条件（空气温度为25摄氏度和43.3摄氏度）下进行。结果表明，佩戴全面罩呼吸器会给研究中使用的高温和工作量所导致的生理压力增加显著负担。六项生理指标中的五项显示出这种生理压力的增加：心率、分钟通气量、耗氧量、能量消耗和口腔温度。对出汗率没有可检测到的影响。尽管主观评分表明随着生理压力增加不适感更强，但这些指标之间观察到的相关性较低（相关系数小于0.60）。显著影响的最终结果表明，工人在高温条件下佩戴呼吸器时对中等或更高水平工作的耐受性降低。佩戴全面罩时这种降低比佩戴半面罩时更明显。建议改变呼吸器设计以最小化呼吸死腔来缓解这个问题。否则，在高温工作场所从事中等或更高水平工作时，为防止因使用呼吸器而产生过度的生理压力，可能需要增加休息时间或限制在这种条件下的工作时间。
