firefighters from hotter climates were excluded in order to control a potentially confounding variable (heat acclimation) and reduce variation in the subject pool . data collection took place during the autumn and winter months to minimise the effect of heat acclimation . Participants provided written informed consent and filled out a medical questionnaire prior to commencement of the study. to ensure they were physically able to perform the protocol. Ethical approval was obtained for this study through the Deakin University Human Research Ethics Committee