Comparison Between Experimental and Heart Rate-Derived Core Body Temperatures Using a Three-Dimensional Whole Body Model

Abstract

Determination of core body temperature (Tc), a measure of metabolic rate, in firefighters is needed to avoid heat-stress related injury in real time. The measurement of Tc is neither routine nor trivial. This research is significant as thermal model to determine Tc is still fraught with uncertainties and reliable experimental data for validation are rare. The objective of this study is to develop a human thermoregulatory model that uses the heart rate measurements to obtain Tc for firefighters using a 3D whole body model. The hypothesis is that the heart rate-derived computed Tc correlates with the measured Tc during firefighting activities. The transient thermal response of the human body was calculated by simultaneously solving the Pennes' bioheat and energy balance equations. The difference between experimental and numerical values of Tc was less than 2.6%. More importantly, a ± 10% alteration in heart rate was observed to have appreciable influence on Tc, resulting in a ± 1.2 °C change. A 10% increase in the heart rate causes a significant relative % increase (52%) in Tc, considering its allowable/safe limit of 39.5 °C. Routine acquisition of the heart rate data during firefighting scenario can be used to derive Tc of firefighters in real time using the proposed 3D whole body model.