Wearable Personal Core Body Temperature Measurement Considering Individual Differences and Dynamic Tissue Blood Perfusion.

Accurate and continuous measurement of the human core body temperature by a wearable device is of great significance for human health care and disease monitoring. The current wearable thermometers ignore the physiological differences between individuals and the role of blood perfusion in thermoregulation, resulting in insufficient accuracy and limitations in terms of the measurement sites. This study proposed a novel personal model for measuring core body temperature by taking dynamic tissue blood perfusion and individual differences into consideration. The technique facilitates possible accurate core body temperature measurements from the skin surface of the wrist and forehead. First, the personal core body temperature model was established based on the thermal equilibrium between the human body and the measurement device, in which the tissue blood perfusion changes dynamically with tissue temperature. Then, the parameters of the personal model that imply individual physiological differences were obtained based on personal data collected daily. The results show that with the developed personal model, the accuracy of the measured body temperature from the wrist is close to that of the forehead model. The wrist model and the forehead model have a mean absolute error of 0.297 (SD = 0.078)°C and 0.224 (SD = 0.071)°C, respectively, which meets the accuracy and robustness requirements of practical applications. The personal models significantly improve the accuracy compared with that of the group model, especially for the wrist model.