Investigation of Core Body Temperature Measurement Method Robust for Environmental Changes

In our society, where the number of people suffering from heat-related illnesses is increasing due to global warming, it is expected to develop a technology to conveniently measure core body temperature under active conditions, which is vital biological information for predicting heat-related illnesses. Measuring methods of core body temperature from thermal flow on the skin surface noninvasively have been reported so far, but the technical problem to be solved is that it cannot cope with changes in ambient temperature and air flow, which easily occur in daily life, and causes large measurement errors. This study aims to develop a new core body temperature measurement method that can respond to environmental changes based on a unique sensor structure and core temperature calculation model. The proposed method has two features. One has a new structure to eliminate the influence of environmental changes on the measurement data. The other is the development of a new calculation model of core body temperature that takes into account the heat capacity of the skin, and features a reduction in measurement errors during unsteady conditions. Here, the effect of the structure and calculation model on the estimation error is analyzed multilaterally through numerical simulation, and the effectiveness of the proposed method is shown by the fact that it can estimate core body temperature with high accuracy over a wide range of temperature and wind speed compared with the conventional method.