Introduction: Exertional heat stroke is a cause of collapse in marathon runners. Rectal temperature (Trectal) measurement is the usual method of estimating core temperature in collapsed runners, and temporal artery thermometer (TAT) measurement is untested for field use in marathon runners and other athletes. The objective of this study is to compare TAT measurement with Trectal measurement in collapsed marathon runners.
Methods: TAT-500i (Exergen Corp, Wellesley, MA) temperature measurements were obtained using the manufacturer's instruction manual on 60 collapsed marathon runners who had Trectal measurements in the finish area medical tent during two consecutive annual races.
Results: The TAT temperatures identified only 2 of 17 hyperthermic runners (Trectal > 39.4°C (103°F)), a sensitivity of only 0.12, and a Pearson' correlation coefficient of 0.374 (r2 = 0.14). Among the 17 hyperthermic runners, the correlation of Trectal to TAT temperatures was 0.526 (r2 = 0.28) with a mean ± SD Trectal of 40.7 ± 0.94°C (105.1 ± 1.7°F) and a mean ± SD TAT temperature of 37.4± 1.3°C (99.4 ± 2.4°F). Among the 43 collapsed normothermic runners, there was no correlation between the rectal and the TAT measurements (r = −0.142, P = 0.37).
Conclusions: These findings indicate that there is little association between the temperatures obtained by temporal artery measurement and Trectal measurement in collapsed marathon runners and that TAT temperature is unable to identify hyperthermic runners. Based on these findings, TAT measurement should not be used to assess core body temperature or make treatment decisions for marathon runners with potential exertional heat stroke.