Baker S J, Grice J, Roby L, Matthews C
School of Sport Health and Exercise Sciences, University of Wales-Bangor, UK.
Ergonomics. 2000 Sep;43(9):1350-8. doi: 10.1080/001401300421798.
The cardiorespiratory and thermal responses of two intensities of treadmill exercise were compared for brief periods (12 min) in fire ensemble (FE) but without self contained breathing apparatus, and sports ensemble (SE), in a temperature environment. A further experiment explored the responses of subjects exercising in FE over a prolonged period (60 min). Eighteen male fire-fighters wearing either FE or SE walked on a level treadmill for 6 min at 5 km x h(-1) increasing to 7 km x h(-1) for 6 min. Following a recovery interval of 1 h, the exercise protocol was repeated in the second ensemble; the order of ensemble was balanced. Heart rate (HR), rectal temperature (Tre), VO2 max and rating of perceived exertion (RPE) were monitored continuously under both ensembles. At 7 km x h(-1), VO2 was significantly higher (p<0.05) in FE (36.1 and 39.9 ml x kg(-1) x min(-1)) than in SE and represented 74% VO2 max. There were no changes Tre. In experiment 2, following a rest interval of at least 36 h, eight subjects in FE walked on the treadmill at 6 km x h (gradient 10%) for 60 min also in temperate conditions, where HR, Tre and RPE were recorded at 10-min intervals. During the 60-min exercise in FE, HR reached 161 beats x min(-1) and Tre increased to 38.3 degrees C. Despite considerable subject discomfort, Tre remained below dangerous levels (38.4 degrees C). When RPE were compared with a physiological strain index (PSI) calculated from Tre and HR data over 60 min, there was no significant difference (p<0.05) with a correlation coefficient (r) of 0.98. The results suggest that RPE and PSI are closely related when exercise is sufficiently prolonged or intense to elevate Tre and HR in fire-fighters wearing FE in temperate conditions. If further investigation confirms this relationship for hot humid conditions in which fire-fighters operate, then with training, it may provide individuals with a valid measure of dangerous levels of perceived heat strain.
在温度环境中，对两组消防员在不佩戴自给式呼吸器的情况下，进行两种强度的跑步机运动（持续12分钟）时的心肺和热反应进行了比较，一组为消防装备组（FE），另一组为运动装备组（SE）。另一项实验探究了消防装备组的受试者在较长时间（60分钟）运动时的反应。18名穿着FE或SE的男性消防员在水平跑步机上以5 km/h的速度行走6分钟，然后增加到7 km/h再走6分钟。经过1小时的恢复间隔后，在另一组装备中重复该运动方案；装备顺序是平衡的。在两种装备情况下，持续监测心率（HR）、直肠温度（Tre）、最大摄氧量（VO2 max）和主观用力程度分级（RPE）。在7 km/h时，FE组的VO2显著更高（p<0.05）（分别为36.1和39.9 ml/kg/min），高于SE组，且代表74%的VO2 max。Tre没有变化。在实验2中，经过至少36小时的休息间隔后，8名FE组的受试者在温带条件下，以6 km/h（坡度10%）的速度在跑步机上行走60分钟，每隔10分钟记录HR、Tre和RPE。在FE组60分钟的运动过程中，HR达到161次/分钟，Tre升高到38.3℃。尽管受试者有相当大的不适感，但Tre仍低于危险水平（38.4℃）。当将RPE与根据60分钟内的Tre和HR数据计算出的生理应变指数（PSI）进行比较时，相关系数（r）为0.98，两者无显著差异（p<0.05）。结果表明，在温带条件下，当穿着FE的消防员进行足够长时间或强度的运动，使Tre和HR升高时，RPE和PSI密切相关。如果进一步的研究证实了这种关系在消防员工作的炎热潮湿条件下也成立，那么通过训练，它可能为个人提供一种有效的感知热应激危险水平的测量方法。
