Comparison of mean skin temperature using `covered' versus `uncovered' contact thermistors

The purpose of this study was to compare the mean skin temperature (Tsk) obtained using 'covered' versus 'uncovered' contact thermistors in a variety of environmental conditions. Ten male subjects walked on a treadmill at 6.4 kph for 30 min in three different environments: thermoneutral (23 degrees C/50% RH), hot-humid (35 degrees C/80%), and hot-dry (42 degrees C/20%). Tsk was measured using three 'uncovered' contact thermistors, and three 'covered' thermistors. The 'uncovered' probes were attached using acrylic rings that allowed the outer surface of the thermistors to have free exchange with the environment. The 'covered' probes were affixed to the skin using foam patches and tape. The latter procedure is commonly used in many research and clinical laboratories. The 'covered' probes resulted in a significantly (p < 0.05) higher Tsk under all three environmental conditions. The largest difference occurred in the thermoneutral condition with the 'covered' Tsk being 1.3 degrees C higher than the 'uncovered' Tsk. These results suggest that covering a contact skin thermistor hinders heat loss and results in an artificially high Tsk. It is hoped that the results of this study will encourage the adoption of 'uncovered' contact skin thermistors in the future.