Abstract
The purpose of this study was to test the validity of the Metrosonics, Inc. hs-3800 personal heat strain monitor in predicting deep-body temperature, measured with a rectal probe (Tre). Fifteen males participated in two sessions walking and arm curling at 300 Kcal/hr for up to 2 hours each in a 26°C wet bulb globe temperature environment wearing two different types of particle barrier, vapor permeable suits common to industry: a melt-blown spunbond polypropylene laminate (PPPC) and a flash-spunbond polyethylene (PEPC), subsequently compared for test-retest reliability. Eight of these subjects performed a third test while wearing an impermeable suit made from Saranex® (coated PEPC) (SAR). Correlations between the hs-3800 and Tre for PPPC were r = 0.58 and r=0.53 for SAR. In the first test of hs-3800 in PPPC, 0 true positives (TP), 10 true negatives (TN), 2 false positives (FP), and 3 false negatives (FN) were observed, yielding a specificity of the hs-3800 in PPPC of 78%. In the subsequent tests of the hs-3800 in the PEPC suit, a sensitivity and specificity of 17 and 75% were observed. The hs-3800 performed reliably in these two independent tests. A 63% sensitivity was obtained for the SAR. Based on the correlations and sensitivity measures, the hs-3800 was more effective for vapor barrier clothing, but these findings indicate that the hs-3800's sensitivity was too low for either PC.