title: The influence of activewear worn under standard work coveralls on whole-body heat loss.
abstract: This study evaluated the influence of activewear undergarments worn under the standard mining coveralls on whole-body heat exchange and change in body heat content during work in the heat. Each participant performed 60 min of cycling at a constant rate of heat production of 400 W followed by 60 min of recovery in a whole-body calorimeter regulated at 40°C and 15% relative humidity donning one of the four clothing ensembles: (1) cotton underwear and shorts only (Control, CON); (2) Activewear only (ACT); (3) Coveralls+Cotton undergarments (COV+COT); or (4) Coveralls+Activewear undergarments (COV+ACT). In the latter two conditions a hard hat with earmuffs, gloves, and socks with closed toe shoes were worn. We observed that both COV+COT and COV+ACT resulted in a similar mean (±SE) change in body heat content, which was significantly greater compared with the CON and ACT during exercise, suggesting that the rate of thermal strain was elevated to a similar degree in both coverall conditions (CON: 245±32 kJ; ACT: 260±29 kJ; COV+COT: 428±36 kJ; COV+ACT: 466±15 kJ; p<0.001). During recovery, the negative change in body heat content was greater for both COV+COT and COV+ACT compared with the CON and ACT but similar between COV+COT and COV+ACT due to the greater amount of heat stored during exercise (CON: -83±16 kJ; ACT: -104±33 kJ; COV+COT: -198±30 kJ; COV+ACT: -145±12 kJ; p=0.048). Core temperatures and heart rate were also significantly elevated for the COV+COT and COV+ACT compared with the CON and ACT conditions during and following exercise (p<0.05). These results suggest that while activewear undergarments are not detrimental, they provide no thermoregulatory benefit when replacing the cotton undergarment worn under the standard coverall during work in the heat.
authors.affiliation: University of Ottawa, Faculty of Health Sciences, Human and Environmental Physiology Research Unit, Ottawa, Canada.
authors.forename: Jill M
authors.initials: JM
authors.lastname: Stapleton
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Hardcastle
authors.forename: Glen P
authors.initials: GP
authors.lastname: Kenny
mesh_terms: D000328:Adult; D001831:Body Temperature; D001833:Body Temperature Regulation; D002151:Calorimetry; D003020:Clothing; D006339:Heart Rate; D006801:Humans; D008297:Male; D008906:Mining; D016273:Occupational Exposure / Q000032:analysis*; D011481:Protective Clothing