Physiological and comfort effects of commercial “wicking” clothing under a bulletproof vest

Abstract

Ballistic protective gear (“bulletproof” vest), required in law enforcement and some branches of the military, contains thick padding and covers much of the surface area of the user's torso. Bulletproof vest (BV) use poses a compromise between protecting one's life from assault and risking possible harm from heat strain injury. Aside from the danger of heat-related injuries, BV may contribute to severe discomfort problems. Therefore, this study examined the effects of a snug-fitting synthetic shirt designed to wick sweat away from the skin worn under BV. Several physiological and comfort parameters were assessed while wearing two different undergarments on two separate occasions (Under Armour {EC} or cotton t-shirt {CT}). Pre- and post-blood and urine samples were collected for determination of percent change in plasma volume (%ΔPV) and urine-specific gravity (USG). Before exercising, participants inserted a rectal thermocouple for the continuous measurement of core temperature. Also, participants were fitted with several skin thermocouples and a heart rate monitor was placed beneath the undergarment. Next, the participants were dressed in the undergarment, trousers, BV, short-sleeved button up shirt, and a military ballistic helmet. Participants performed a simulated industrial protocol for ∼2 h. Results showed no significant difference between trials (EC vs. CT) for rectal temperature and all skin temperatures except for chest temperature, which was significantly lower while wearing EC. There were also no significant differences between trials for %ΔPV, USG, or heart rate. Furthermore, there were no significant differences between trials for any subjective or comfort measure. Results suggest that EC offers no advantage in cooling the wearer over CT. Additionally, even though there were no significant differences between ensembles for subjective measures, trends were observed with EC being perceived as being more comfortable.