title: Reduction of Physiological Strain Under a Hot and Humid Environment by a Hybrid Cooling Vest.
abstract: Chan, APC, Yang, Y, Wong, FKW, Yam, MCH, Wong, DP, and Song, W-F. Reduction of physiological strain under a hot and humid environment by a hybrid cooling vest. J Strength Cond Res 33(5): 1429-1436, 2019-Cooling treatment is regarded as one of good practices to provide safe training conditions to athletic trainers in the hot environment. The present study aimed to investigate whether wearing a commercial lightweight and portable hybrid cooling vest that combines air ventilation fans with frozen gel packs was an effective means to reduce participants' body heat strain. In this within-subject repeated measures study, 10 male volunteers participated in 2 heat-stress trials (one with the cooling vest-COOL condition, and another without-CON condition, in a randomized order) inside a climatic chamber with a controlled ambient temperature 33° C and relative humidity (RH) 75% on an experimental day. Each trial included a progressively incremental running test, followed by a 40-minute postexercise recovery. Core temperature (Tc), heart rate (HR), sweat rate (SR), rating of perceived exertion (RPE), exercise duration, running distance, and power output were measured. When comparing the 2 conditions, a nonstatistically significant moderate cooling effect in rate of increase in Tc (0.03 ± 0.02° C·min for COOL vs. 0.04 ± 0.02° C·min for CON, p = 0.054, d = 0.57), HR (3 ± 1 b·min·min for COOL vs. 4 ± 1 b·min·min for CON, p = 0.229, d = 0.40), and physiological strain index (PSI) (0.20 ± 0.06 unit·min for COOL vs. 0.23 ± 0.06 unit·min for CON, p = 0.072, d = 0.50) was found in the COOL condition during exercise. A nonstatistically significant (p > 0.05) trivial cooling effect (d < 0.2) was observed between the COOL and CON conditions for measures of exercise duration, running distance, power output, SR, and RPE. It is concluded that the use of the hybrid cooling vest achieved a moderate cooling effect in lowering the rate of increase in physiological strain without impeding the performance of progressively incremental exercise in the heat.
authors.affiliation: Department of Building and Real Estate, The Hong Kong Polytechnic University, The Hong Kong Special Administrative Region, China.
authors.forename: Albert P C
authors.initials: APC
authors.lastname: Chan
authors.affiliation: Department of Building and Real Estate, The Hong Kong Polytechnic University, The Hong Kong Special Administrative Region, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Building and Real Estate, The Hong Kong Polytechnic University, The Hong Kong Special Administrative Region, China.
authors.forename: Francis K W
authors.initials: FKW
authors.lastname: Wong
authors.affiliation: Department of Building and Real Estate, The Hong Kong Polytechnic University, The Hong Kong Special Administrative Region, China.
authors.forename: Michael C H
authors.initials: MCH
authors.lastname: Yam
authors.affiliation: Sport Science Research Center, Shandong Sport University, Jinan, China.
authors.forename: Del P
authors.initials: DP
authors.lastname: Wong
authors.affiliation: Laboratory for Clothing Physiology and Ergonomics (LCPE), The National Engineering Laboratory for Modern Silk, Soochow University, Suzhou, China.
authors.forename: Wen-Fang
authors.initials: WF
authors.lastname: Song
mesh_terms: D000293:Adolescent; D000328:Adult; D056352:Athletes; D001831:Body Temperature / Q000502:physiology; D001833:Body Temperature Regulation / Q000502:physiology*; D017679:Cryotherapy / Q000379:methods*; D004867:Equipment Design; D015444:Exercise / Q000502:physiology; D006339:Heart Rate / Q000502:physiology; D018882:Heat Stress Disorders; D006358:Hot Temperature; D006801:Humans; D006813:Humidity; D008297:Male; D005082:Physical Exertion / Q000502:physiology; D011481:Protective Clothing; D012420:Running / Q000502:physiology; D012881:Skin Temperature; D013546:Sweating / Q000502:physiology; D055815:Young Adult