Abstract
The brain is the organ most vulnerable to heat stress. This vulnerability manifests as impaired cognition, orthostatic tolerance, work capacity and eventually, brain death. The cause is often ascribed to inappropriate cerebral blood flow (CBF), but elevated intracranial pressure (ICP) is commonly observed in animal models of heat stroke.
Therefore, we aimed to answer three previously-unknown questions: 1) what is the effect of heat stress on ICP in humans; 2) how does ICP interact with CBF at thermal tolerance; and 3) do these depend on the mode of heating? We hypothesized that decreases in CBF would contribute to thermal intolerance but protect against increases in ICP, and that decreased CBF would be most pronounced in passive hot air exposure.