Influence of a new vapor protective clothing layer on physical work tolerance times at 40 degrees C

The purpose of the present study was to examine the influence of a new vapor protective clothing on physical work performance in a hot environment (40 degrees C and 25% relative humidity). Eleven unacclimatized males (28 +/- 6 years, 79 +/- 8 kg, 1.76 +/- 0.06 m) were assigned to exercise at either a light intermittent (L) (N = 6), or heavy continuous (H) (N = 5) metabolic rate. Group L alternated between 15 min of walking on a treadmill at 1.11 m.s-1 with a 0% grade and 15 min of rest. Group H walked continuously at 1.33 m.s-1 with a 3% grade. Subjects were tested wearing three clothing configurations: full nuclear, biological and chemical (NBC) protection (TOPP High) with the combat clothing worn under the NBC garment (TH + CC); full NBC protection without combat clothing (TH - CC); the new vapor protective clothing together with the NBC gloves, boots, and respirator (NPC). WTT was the time-period until rectal temperature (Tre) reached 39.3 degrees C, heart rate reached 95% maximum, dizziness or nausea precluded further exercise, or 3 h had elapsed. For group L, WTT was similar for TH + CC (113 +/- 12 min) and TH - CC (139 +/- 18 min). WTT was significantly increased for NPC where all subjects completed the 3 h in the climatic chamber. The rate of increase for Tre was significantly reduced for NPC (0.3 +/- 0.1 degree C.h-1) compared with both TH + CC (0.9 +/- 0.1 degree C.h-1) and TH - CC (0.8 +/- 0.2 degree C.h-1).(ABSTRACT TRUNCATED AT 250 WORDS)