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

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; skin temperature, T; torso microclimate temperature/humidity, M/M; oxygen uptake, VO; Heart rate, HR) and cognitive (reaction time, number of errors) and subjective responses. While some elements of T, T, M, and HR reduction in the Vest trial were observed, these decrements were small and persisted only for a short period of time. VO 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.