Conventional and novel body temperature measurement during rest and exercise induced hyperthermia.

Despite technological advances in thermal sensory equipment, few core temperature (T) measurement techniques have met the established validity criteria in exercise science. Additionally, there is debate as to what method serves as the most practically viable, yet upholds the proposed measurement accuracy. This study assessed the accuracy of current and novel T measurement techniques in comparison to rectal temperature (T) as a reference standard. Fifteen well-trained subjects (11 male, 4 female) completed 60min of exercise at an intensity equating to the lactate threshold; measured via a discontinuous exercise test. T was significantly elevated from resting values (37.2±0.3°C) at the end of moderate intensity exercise (39.6±0.04°C; P=0.001). Intestinal telemetric pill (T) temperature and temporal artery temperature (T) did not differ significantly from T at rest or during exercise (P>0.05). However, aural canal temperature (T) and thermal imaging temperature (T) were both significantly lower than T (P<0.05). Bland Altman analysis revealed only T was within acceptable limits of agreement (mean bias; 0.04°C), while T, T and T demonstrated mean bias values outside of the acceptable range (>0.27°C). Against T, these results support the use of T over all other techniques as a valid measure of T at rest and during exercise induced hyperthermia. Novel findings illustrate that T (when measured at the inner eye canthus) shows poor agreement to T during rest and exercise, which is similar to other 'surface' measures.