Recent developments of an active ventilated vest for military use

Previous research has shown that an active ventilated vest can provide physiological and perceptual benefits regarding the thermal strain of a soldier. In the present article further design integration and technical developments of a ventilated vest worn in combination with Personal Frotective Equipment (PPE) are described: step l;technical improvements, step 2. improved functionaliry, step 3; comparison of subjective experience with commercially available passive ventilation vest during field study. To improve integration with the current ballistic system, the connoller of the ventilated vest and its cables were simplified. Additionally, the new version of the ventilated vest was connected with the battery of the existing energy supply system. To improve and provide extra functionality intermittent ventilation was added. When using this intermittent ventilation, battery life was extended from -10 to -25 hours, while maintaining similar skin temperature compared to continuous ventilated modes, and lower skin temperature compared to a control condition (P<0.05). An additional benefit of intermittent cooling was an improved cooling sensation (P<0 05) compared to continuous cooling at similar fan speeds. To evaluate operational usability and perceptions for the newest version ofthe ventilated vest, a 5-day field study was performed during a military training in the heat (daily max. temperature: 45.2 + 1.2"C, daily mean relative humidity: 25.5 + 3.6%). The ventilated vest was compared to a commercially available passive ventilated vest. It was found that the active ventilated vest was perceived as more operationally usable (P<0.04). more comfortable (P<0.001), less warm (P=0.002), and its use resulted in a higher perception of cooling (P<0.001), compared to the passive vest. About 80% of the time soldiers chose full fan speed continuous ventilation during the field study. To conclude, the updated ventilated vest was subjectively evaluated as more operational usable, compared to the passive ventilated vest, especially during light intensity work, transport and breaks.