A Wearable System for Remote Wrist Skin Temperature Monitoring to Assess Skin Thermal Response to Extreme Cold: A Case Study.

Skin temperature measurement is a complex issue. Skin tissue is one of the main thermoregulatory organs and takes major responsibility for heat exchange in the organism. Accurate skin temperature measurement may contribute to better estimation of deep core temperature, which is why enhancing possibilities of skin temperature measurement is considered substantial. However, the real value of the skin temperature can be influenced by many biological and non-biological factors. Some of the external factors such as extensive wind or extreme ambient temperature may significantly influence the raw value of the skin temperature regardless of the choice of the measuring point. Despite that, abnormal thermoregulatory behaviour can occur due to internal body stresses and reactions. Whilst internal influence is even more difficult to track than external factors, it is crucial to monitor and identify the thermal stresses in a correct way. The paper proposes a wrist temperature measurement system. The system consists of a sensory part placed in a housing adapted to the shape of the wrist. The sensory component enables contact measurement of wrist skin temperature under the assumed experimental conditions. The housing is designed to provide stable positioning of the sensory component relative to the wrist while simultaneously isolating it from external conditions. The paper presents the results of a case study concerning human thermoregulation, quantifying the thermal response of the hand under low-temperature exposure in temperature chamber and during the subsequent rewarming phase after removal. During the experiment, temperature measurements of both hands were recorded. One of the co-authors participated in this case experiment. The temperature measurement results were compared between the hand subjected to thermal stress and the hand not exposed to low temperatures. Differences in the participant response to repeated thermal stress are demonstrated. The results highlight the complexity of the human body's thermoregulation process in extremely cold environments.