Moran D S, Shitzer A, Pandolf K B
United States Army Research Institute of Environmental Medicine, Natick, Massachusetts 01760-5007, USA.
Am J Physiol. 1998 Jul;275(1):R129-34. doi: 10.1152/ajpregu.1998.275.1.R129.
A physiological strain index (PSI), based on rectal temperature (Tre) and heart rate (HR), capable of indicating heat strain online and analyzing existing databases, has been developed. The index rates the physiological strain on a universal scale of 0-10. It was assumed that the maximal Tre and HR rise during exposure to exercise heat stress from normothermia to hyperthermia was 3 degrees C (36.5-39.5 degrees C) and 120 beats/min (60-180 beats/min), respectively. Tre and HR were assigned the same weight functions as follows: PSI = 5(Tret - Tre0) . (39.5 - Tre0)-1 + 5(HRt - HR0) . (180 - HR0)-1, where Tret and HRt are simultaneous measurements taken at any time during the exposure and Tre0 and HR0 are the initial measurements. PSI was applied to data obtained from 100 men performing exercise in the heat (40 degrees C, 40% relative humidity; 1.34 m/s at a 2% grade) for 120 min. A separate database representing seven men wearing protective clothing and exercising in hot-dry and hot-wet environmental conditions was applied to test the validity of the present index. PSI differentiated significantly (P < 0.05) between the two climates. This index has the potential to be widely accepted and to serve universally after extending its validity to women and other age groups.
一种基于直肠温度（Tre）和心率（HR）的生理应变指数（PSI）已被开发出来，它能够在线指示热应激并分析现有数据库。该指数在0 - 10的通用尺度上对生理应变进行评级。假定在从正常体温到高热的运动热应激暴露期间，Tre和HR的最大上升分别为3摄氏度（36.5 - 39.5摄氏度）和120次/分钟（60 - 180次/分钟）。Tre和HR被赋予相同的权重函数，如下所示：PSI = 5(Tret - Tre0)·(39.5 - Tre0)-1 + 5(HRt - HR0)·(180 - HR0)-1，其中Tret和HRt是暴露期间任何时间同时进行的测量值，Tre0和HR0是初始测量值。PSI被应用于从100名男性在高温环境（40摄氏度，相对湿度40%；坡度2%，风速1.34米/秒）中进行120分钟运动所获得的数据。一个单独的数据库，代表七名穿着防护服并在干热和湿热环境条件下运动的男性，被用于测试本指数的有效性。PSI在两种气候之间有显著差异（P < 0.05）。该指数在将其有效性扩展到女性和其他年龄组后，有可能被广泛接受并普遍适用。
