Article Title



Cody R. Smith, Cory L. Butts, Brendon P. McDermott; University of Arkansas, Fayetteville, AR; e-mail: crs01@uark.edu

Performing industrial work in a hot environment increases thermal discomfort and could decrease work productivity (WP). There is limited research on the effect of external phase change cooling (PCC) modalities in an industrial work setting. PURPOSE: Examine the effect of a PCC garment on perceptual responses and WP while performing industrial work in a hot environment. METHODS: Twenty male participants (24 ± 3y, 75.0 ± 10.7kg, 13.6 ± 5.2% body fat, 1.93 ± 0.17m2 body surface area) completed two randomized trials in an environmental chamber (34.2 ± 0.06°C, 54.6 ± 0.5% relative humidity) wearing a compression shirt and shorts, a fire rated coverall suit, a hard hat, and gloves. PCC packs (8 total; solid to a liquid at 10°C) were inserted in the front and back of the compression garments for our PCC trial, and no cooling packs for a control (CON) trial. Each trial included two identical 20min. periods of industrial work (W1, W2): five min. each of treadmill walking (3.0mph, 2% grade), lifting/carrying 11.3kg boxes, loosening and tightening nuts to bolts, and carrying 3.6kg dumbbells over steps followed by a five min. break. Participants then completed a 15 min. WP assessment (as many repetitions as possible in 15 min. of lifting and transporting five 11.3 kg. boxes, loosening and tightening six nuts to bolts, and carrying 3.6 kg. dumbbells over steps and back 5 times), three min. of standing recovery (R3), and seven min. of seated recovery (R10). Thermal sensation (0-8 scale; TS), thirst (1-9 scale; Th), and rating of perceived exertion (6-20 scale; RPE) were assessed pre and post W1, W2, WP, and at R3 and R10. Fatigue (1-7 scale; FS), and muscle pain (0-10 scale) were assessed post W1, W2, and WP. Perceptual strain index (PS) was calculated post W1, W2, and WP. RESULTS: TS was lower in PCC compared to CON pre WP (P=0.007). Th was lower in PCC compared to CON post W1 (P=0.034). Overall, Th was lower in PCC compared to CON WP and recovery (P=0.008). RPE was lower in PCC compared to CON throughout (P≤0.05). FS was lower in PCC compared to CON throughout trials (P=0.023). PS was lower in PCC compared to CON throughout trials (P=0.002). Participants completed 5.59 ± 1.07 repetitions in CON and 5.84 ± 1.05 repetitions in PCC (P=0.097). CONCLUSION: Perceptual benefits for Th, RPE, FS, and PS were shown when using the cooling garment while WP was not increased. Wearing PCC garments improves subjective feelings and may enhance job satisfaction while working in a hot environment.

Funding provided by PreventaMed, Inc.

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