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Effects of different ambient conditions on thermo-physiological responses to wearing CBRN ensemble.

Authors
Powell-JB; Kim-J-H; Coca-A; Roberge-R
Source
Med Sci Sports Exerc 2013 May; 45(5S)(Suppl 1):347
NIOSHTIC No.
20043830
Abstract
PURPOSE: This study was conducted to determine the effect of different ambient conditions on thermo-physiological responses of CBRN ensemble wearers performing work in order to provide information regarding exposure limits and rest schedules. METHODS: Eight healthy males (VO2max >/= 50ml/kg/min) completed two trials of a heat stress test (4.8 km/h, 3% grade) while wearing a CBRN ensemble in neutral (22C, 50%RH) and hot/humid (35C, 65% RH) ambient conditions. The study variables included body core (Tre) and skin temperatures (Tsk), heart rate (HR), respiratory parameters (VO2, VE), and microclimate temperature/humidity (Tmicro, RHmicro). Two-way repeated measures ANOVA (Conditions Time) was carried out for statistical analysis. RESULTS: The study results indicated there was a significant main effect for ambient conditions and time in all thermoregulatory and respiratory variables (p<0.001). A pairwise comparison showed significant final measurement values in Tre (38.16+/-0.29 VS. 39.73+/-0.30 C), Tsk (36.42+/-0.30 VS. 39.12+/-0.37 C), HR (152.9+/-18.2 vs. 187.1+/-2.1 beats/min), VO2 (1.59+/-0.2 VS. 2.03+/-0.2 L/min), VE (47.7+/-6.0 VS. 59.3+/-10.1 L/min) between neutral and hot/humid conditions, respectively (p<0.001). Tmicro was also significantly elevated in the hot/humid environment (35.1 VS. 38.6 C), whereas RHmicro reached >/= 95% at 15min exercise in both conditions, significantly hindering evaporative heat loss to the environment. CONCLUSIONS: Working while wearing vapor resistant CBRN ensemble imposes a significant thermo-physiological stress on a wearer. This study showed ambient conditions also have a significant impact on the level of thermal strain, mainly due to diminished evaporative capacity and elevated Tmicro. Environmental conditions need to be taken into account to determine work exposure limits and rest cycles for individuals wearing a CBRN ensemble.
Keywords
Physiological-response; Physiological-measurements; Physiological-stress; Physiological-testing; Personal-protective-equipment; Protective-clothing; Protective-equipment; Humans; Men
CODEN
MSPEDA
Publication Date
20130501
Document Type
Abstract
Fiscal Year
2013
NTIS Accession No.
NTIS Price
Issue of Publication
5S
ISSN
0195-9131
NIOSH Division
NPPTL
Source Name
Medicine and Science in Sports and Exercise
State
PA
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