title: Clothing adjustments for concealed soft body armor during moderate physical exertion.
abstract: Previous research has studied the impact of Level II concealed soft body armor (SBA) on the augmentation of heat storage in a hot environment simulating a typical summer day in the southeastern United States (wet bulb globe temperature [WBGT] = 30°C) and noted a significant difference between macro- and micro-WBGTs. The purpose of this study was to characterize the microclimate (micro-WBGT) under a concealed Level II SBA during 60 min of moderately intense work at two separate macro-WBGTs (26°C and 30°C), and to establish WBGT corrections to allow prediction of heat strain in an individual wearing a concealed Level II SBA. A single trial was performed with nine volunteers (27 ± 4 years) outfitted with a simulated standard law enforcement uniform and a traditional concealed Level II SBA, in a moderately warm environment (WBGT = 26°C). Each participant performed cycles of 12 min of walking (1.25 L · min(-1)) and 3 min of arm curls (14.3 kg, 0.6 L · min(-1)) with a 5 min rest after every other cycle, for a total of 60 minutes. This trial was compared to an identical previously completed 60-min work bout at 30°C. A two-way repeated measures ANOVA with Post hoc Bonferroni and paired samples t-test analysis was conducted. A greater difference between macro- micro-WBGTs existed at 26°C compared to the 30°C macro-WBGT. Under these conditions, a moderate work in Level II SBA requires a WBGT correction of 8.9°C and 6.2°C at macro-WBGTs of 26°C and 30°C, respectively. A modified simple linear regression prediction model was established for mean Micro-WBGT for each macro-WBGTs after the plateau point at the 30 min mark. The derivation regressions at 26°C (R(2) = 0.99), and 30°C (R(2) = 0.99) indicate that micro-WBGT could be predicted for each 15 minutes time at both macro-WBGTs tested for individuals doing moderate intensity (300 Kcals · hr(-1)) work wearing concealed Level II SBA.
authors.affiliation: a Department of Health and Human Performance , The University of Montana Western , Dillon , Montana.
authors.forename: Greg A
authors.initials: GA
authors.lastname: Ryan
authors.forename: Stacy H
authors.initials: SH
authors.lastname: Bishop
authors.forename: Robert L
authors.initials: RL
authors.lastname: Herron
authors.forename: Charles P
authors.initials: CP
authors.lastname: Katica
authors.forename: Bre'anna L
authors.initials: BL
authors.lastname: Elbon
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Bosak
authors.forename: Phillip
authors.initials: P
authors.lastname: Bishop
mesh_terms: D000328:Adult; D001831:Body Temperature / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D016273:Occupational Exposure; D005082:Physical Exertion / Q000502:physiology; D016495:Police; D011481:Protective Clothing; D015144:Southeastern United States; D013696:Temperature
keywords: WBGT; law enforcement; micro-environment; thermoregulation; vest