The new method was found to perform well in an extreme car racing setting. It has the potential to be used in other applications, including the industrial and aerospace sectors.

The cardiovascular system of drivers is considerably stressed at extremely high HR. This high average HR positively correlated with mean speed ratio, suggesting that faster driving speed would induce greater cardiovascular stress to professional drivers during actual races. However, contrary to our hypothesis, cabin temperature was not significantly correlated with average HR. It is speculated that direct body cooling systems used in this professional race category work well against increases in HR by thermal stress under the temperature range found herein.

Motor racing athletes, especially Grand Touring (GT) car racing drivers in the closed-cockpit category, can face lifethreatening situations caused by heat stroke. In this paper, a novel continuous tympanic temperature monitoring system, that could help to reduce this risk, is presented. The system consists of an earpiece containing an infrared-radiation-type tympanic thermometer and a micro-speaker. We validated the reliability of the system for tympanic temperature monitoring in 10 healthy volunteers (21.8 ± 1.0 S.D. years) using a temperature-controlled water bath. In addition, we evaluated the usefulness of the system with 2 professional drivers under real racing conditions in the 2010 SUPER GT International Series. The results showed strong correlation between the infraredradiation tympanic temperature obtained by the present system and both the direct tympanic temperature (r = 0.994, n = 1119, P < 0.001) and the sublingual temperature (r = 0.972, n = 1119, P < 0.001) as a reference temperature. The mean difference between these temperatures was +0.09 °C, and -0.08 °C, and 95 % confidence interval (equal to 1.96 S.D.) was 0.21 °C, and 0.44 °C, respectively. In the field test, involving real competitive racing under severe conditions on a racing circuit, the system functioned well. These results suggest that our novel system has an acceptable performance in a race setting as a reliable tympanic temperature monitor and could help to improve safety of motor sports.