Efficacy of a prototype ventilated vest in mitigating physiological and cognitive impairments during simulated military tasks in hot environments.

Abstract

Many occupations, including military and industrial, cannot benefit from large-scale cooling strategies; therefore, personal cooling strategies may be more appropriate. We assessed the efficacy of a ventilated vest (Vest) based on participant' autonomic and cognitive responses during military-related activities in the heat. Male soldiers conducted 90-min trials in 35 °C ambient temperature and 40% relative humidity: i) March with/without Vest (N = 10), ii) Guard duty with/without Vest (N = 8). During each trial, we monitored their physiological (gastrointestinal temperature, T_gi; skin temperature, T_skin; torso microclimate temperature/humidity, M_T/M_RH; oxygen uptake, VO₂; Heart rate, HR) and cognitive (reaction time, number of errors) and subjective responses. While some elements of T_gi, T_skin, M_T, and HR reduction in the Vest trial were observed, these decrements were small and persisted only for a short period of time. VO₂ was significantly affected by the exercise but unaffected by the Vest (with vs. without) (p > 0.05). Cognitive performance did not improve significantly with the use of the Vest. However, reaction time improved after both trials. Sweat accumulation in the near-to-skin clothing layer was 2x (March) and 9x (Guard) higher (p < 0.001) without the vest, and participants reported feeling more comfortable and cooler when wearing the vest. The significantly lower sweat accumulation in the next-to-skin clothing layers when wearing the Vest improved thermal comfort and sensation, which was not reflected in the autonomic and cognitive response under the prevailing conditions. Possibly, a more powerful and upgraded concept of the vest could result in improved physiological and cognitive performance.