Degree Name

Master of Science (Research)


School of Health Sciences - Division of Health & Behavioural Sciences


Extensive research into the physiological impact of wearing thermal protective clothing has been conducted for many years. However, the current literature does not provide a consensus concerning the interaction of heat strain and cognitive function. This project sought to investigate the problems associated with personnel working in uncompensable environmental conditions while wearing Australian Defence Force (ADF) protective clothing. Four separate investigations were conducted. The first was a field based study evaluating the thermal influences of operating a helicopter simulator. The second was a laboratory study evaluating the impact of wearing body armour on physiological and cognitive function. Thirdly, a theoretical evaluation of, the problems associated with performing work in an uncompensable heat stress environment and, the physical characteristics of various coolants and cooling systems were investigated. Finally, a laboratory investigation on the physiological and cognitive consequences of wearing a personal protective ensemble while performing exercise with and without an activated liquid-cooling garment. A significant reduction in flying performance was evident when pilots were heated to a mean skin temperature (TGsk) of~39EC compared to the other two conditions (~33EC and 37EC, P less than 0.05), using a water perfusion garment to achieve these target TGsk. However no obvious detriments in cognitive performancewere observed for the two laboratory based studies even though subjects were exposed to a significant thermal load, as determined by increases in TC, TGsk and fc (P less than 0.05). For the final study, where thermal strain was significantly higher in the hot-dry trial without cooling (P less than 0.05), resulting in a terminal rectal temperature that was 1.6EC higher than the thermoneutral condition, the liquid-cooling garment (water temperature 15EC) successfully prevented all detriments in physiological function observed during the hot-dry trial without cooling. It can therefore be concluded from this investigation that, individuals exposed to extreme environmental conditions while wearing protective ensembles, are at risk of developing increased thermal strain that may lead to heat illness. In terms of cognitive function assessment, this project failed to determine specifically, which areas of cognitive function are in fact adversely affected. However, a reduction in thermal strain can be achieved with the use of an auxiliary cooling device

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Unless otherwise indicated, the views expressed in this thesis are those of the author and do not necessarily represent the views of the University of Wollongong.