2007, Piran, Slovenia

Personal protective equipment
approximately 35% of whole-body heat loss (45 W). During exercise (150 W at 25°C), heat
loss from the head can increase about threefold (130 W: Rasch et al., 1991), although this
may now represent a smaller relative contribution. In clothed and hot states, where heat loss
from the limbs and torso is impeded and convective cooling minimised, evaporative cooling
of sweat from the head, and of moisture from the respiratory tract, become the dominant
means for heat dissipation. It is quite probable that the helmet, even though it possessed
internal supports to keep it away from the scalp, impeded this evaporative cooling to the
extent that it may become “the straw that breaks the camel’s back”.
However, while the combat body and head armour significantly increased thermal and
cardiovascular strain, it is unlikely that such loads would lead to either exertional heat illness
or impaired cognitive function in hot-humid conditions, during routine, and uneventful urban
patrol activities in well-hydrated, healthy and physically-active individuals.
ACKNOWLEDGEMENT
This project was funded by the Defence Science and Technology Organisation, Australia.
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