A modified Kalman filter-based model for core temperature estimation during exercise and recovery with/without personal cooling interventions. (October 2022)

• Record Type: Journal Article
• Authors: Rizvi, Ikhtedar Husain; Udayraj,
• Is Part Of: Journal of thermal biology. Volume 109(2022)
• Publication Date: 2022-10
• Subjects: Core temperature estimation -- Kalman filter -- Extended Kalman filter -- Non-invasive method -- Personal cooling clothing -- Real-time monitoring; Thermobiology -- Periodicals; Temperature -- Periodicals; Biology -- Periodicals; Thermobiologie -- Périodiques; Thermobiology; Periodicals; 571.46
• DOI: 10.1016/j.jtherbio.2022.103307
• Languages: English
• ISSNs: 0306-4565

Abstract

Abstract: One of the most important parameters to consider while analysing heat related illness is the human body core temperature. It is therefore required to monitor real-time core temperature in an ambulatory situation for industrial workers, athletes, military personnel, and a variety of other people. As conventional methods of monitoring core temperature are unsuitable for ambulatory use or prohibitively expensive, it is necessary to develop a reliable, inexpensive and non-invasive method for real-time measurement of core temperature. Kalman filter based models for core temperature estimation are found promising to meet these requirements. In this work, we have highlighted one of the major shortcomings of the existing extended Kalman filter model and proposed a modification. The modified extended Kalman filter based model has better performance compared to the existing model in estimating the core temperature as it considers two separate measurement models for exercise and recovery periods. The proposed modified model is validated using human trials data which includes participants wearing regular clothing and different types of personal cooling clothing. It is found that the proposed modified model can predict core temperature more accurately (bias= −0.03 to −0.06°C, LoA=±0.14 – ±0.32°C, and RMSE=0.09–0.16°C) as compared to the existing model (bias=−0.03 – 0.08°C, LoA=±0.26 – ±0.33°C, and RMSE=0.14°C–0.18°C). Personal cooling intervention minimises core temperature rise significantly and thus helps in heat stress mitigation. It is observed that the proposed modified model can estimate core temperature more accurately for cooling intervention cases and intermittent working cases as compared to the existing model. It can be used effectively in an ambulatory setting, but for situations where higher accuracy is required and invasiveness of the method is not a concern, direct contact method of core temperature is always preferred as the proposed model has varying accuracy levels between individuals. Highlights: Real-time estimation of core temperature is vital to prevent heat related illness. Extended Kalman filter based model utilizing non-invasive measurements is proposed. Proposed model considers separate measurement models during exercise and recovery. Performance of the proposed model found to be better than the existing model. Proposed model can also be used reliably for cases involving cooling interventions.