Year of Award

2015

Document Type

Thesis

Degree Type

Master of Science (MS)

Degree Name

Health and Human Performance (Exercise Science Option)

Department or School/College

Department of Health and Human Performance

Committee Chair

Charles Dumke

Commitee Members

Brent Ruby, Joseph Domitrovich, Carl Seielstad

Keywords

skin blood flow, firefighter, heat strain, personal protective clothing, laser Doppler

Publisher

University of Montana

Subject Categories

Exercise Science

Abstract

Protective clothing worn by wildland firefighters (WLFF) may increase physiological strain and heat stress factors due to increased insulation and decreased ventilation. PURPOSE: To examine the effects of a flame resistant synthetic material base layer on heat stress factors. METHODS: Ten recreationally active males (25 ± 6.1 yrs, 80.9 ± 8.4 kg, 11.1 ± 5.3% fat, 4.4 ± 0.6 L·min-1 VO2 max) completed two trials of intermittent (50 min walking, 10 min sitting) treadmill walking (4km/hr, 4% grade) over 3 hours in a hot, dry environment (35⁰C, 30% rh). Participants wore standard WLFF Nomex green pants, Nomex yellow shirt with either a 100% cotton (C) or flame resistant synthetic material base layer (S), while carrying a 16kg pack, hard hat, and gloves. Exercise was followed by a 30 minute rest period without the pack, hard hat, gloves, and Nomex yellow shirt. Core (Tc) and skin (Tsk) temperatures were measured continuously throughout the trial. Physiological strain index (PSI) was calculated using heart rate and Tc. Skin blood flow (SBF) was recorded for two minutes prior to walking, for five minutes during each break, and for three, five minute periods during the 30 minutes following exercise. Water was scripted at 8 ml/kg/hr. RESULTS: No significant differences were found for Tc (p=0.077) and Tsk (p=0.086) between C and S. Significant main effects for time were found for Tc (p

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© Copyright 2015 Matthew C. Dorton