Evaluation of a new system to determine wireless real-time skin temperature

Abstract To evaluate the body’s thermal status, it is essential to determine the mean skin temperature, ideally using wireless technology with real-time feedback. Such a system was not yet available. Therefore, the aim of current study was to examine the in- and ex-vivo validity and reliability of an innovative skin temperature sensor. New skin temperature sensors, named eTemp Performance, were developed with memory and direct read-out capabilities as an alternative to commonly used wireless iButton sensors that provide no real-time feedback. The time constant and precision of the sensors were evaluated by immersion in water baths and human experiments during exercise in the heat. The absolute skin temperature values measured with the eTemp Performance sensors and iButtons were compared to a calibrated gold standard with a variation during measurements of 0.12 °C. The time constant in water of the eTemp Performance sensors was 10.5 ± 1.1 s and 25.8 ± 3.3 s for the iButtons. The mean absolute offset from the standard was 0.06 ± 0.04 °C for the eTemp Performance sensors and 0.19 ± 0.03 °C for the iButtons ( p < 0.001). Human experiments showed no differences between eTemp Performance sensors and iButtons in mean skin temperature values during exercise in the heat. The eTemp Performance sensors are recommended for assessment of mean skin temperature determination since they have a response time in water that is 2.5 times shorter than that of the iButtons, a lower mean absolute offset from the standard than iButtons, and yield similar mean skin temperatures during exercise in the heat.