A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational field

IntroductionEarly identification of hypothermia or hyperthermia is of vital importance, and real-time monitoring of core temperature (CT) of the workers exposed to thermal environments is an extremely valuable tool. From the existing literature studies, the model developed by Buller et al. in their...

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Main Authors: Tiziana Falcone, Simona Del Ferraro, Vincenzo Molinaro, Loredana Zollo, Paolo Lenzuni
Format: Article
Language:English
Published: Frontiers Media S.A. 2024-03-01
Series:Frontiers in Public Health
Subjects:
Online Access:https://www.frontiersin.org/articles/10.3389/fpubh.2024.1219595/full
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author Tiziana Falcone
Simona Del Ferraro
Vincenzo Molinaro
Loredana Zollo
Paolo Lenzuni
author_facet Tiziana Falcone
Simona Del Ferraro
Vincenzo Molinaro
Loredana Zollo
Paolo Lenzuni
author_sort Tiziana Falcone
collection DOAJ
description IntroductionEarly identification of hypothermia or hyperthermia is of vital importance, and real-time monitoring of core temperature (CT) of the workers exposed to thermal environments is an extremely valuable tool. From the existing literature studies, the model developed by Buller et al. in their study of 2013 that generates real-time estimates of CT from heart rate (HR) measurements using the Kalman filter (KF) shows good potential for occupational application. However, some aspects could be improved to reliably handle the existing very wide range of workers and work activities. This study presents a real-time CT estimation model, called the Biphasic Kalman filter-based (BKFB) model, based on HR measurement, with characteristics suited to application in the occupational field.MethodsThirteen healthy subjects (six female and seven male) were included in the study to perform three consecutive tasks simulating work activities. During each test, an ingestible CT sensor was used to measure CT and a HR sensor to measure HR. The KF methodology was used to develop the BKFB model.ResultsAn algorithm with a biphasic structure was developed using two different models for the increasing and decreasing phases of CT, with the ability to switch between the two based on an HR threshold. CT estimates were compared with CT measurements, and with respect to overall root mean square error (RMSE), the BKFB model achieved a sizeable reduction (0.28 ± 0.12°C) compared to the Buller et al. model (0.34 ± 0.16°C).DiscussionThe BKFB model introduced some modifications over the Buller et al. model for a more effective application in the occupational field. It was developed using data collected from a sample of workers (heavily weighted toward middle-aged, not very fit, and with a considerable fraction of female workers), and it also included two different modeling of CT (for the up- and down-phases), which allowed for better behavioral modeling in the two different stages. The BKFB model provides CT estimates reasonably in comparison to the measured intra-abdominal temperature values in both the activity and recovery phases but is more practical and easier to use for a real-time monitoring system of the workers' thermal states.
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spelling doaj.art-5241e851e0be4f2fa08f184ced997e5e2024-03-11T05:03:45ZengFrontiers Media S.A.Frontiers in Public Health2296-25652024-03-011210.3389/fpubh.2024.12195951219595A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational fieldTiziana Falcone0Simona Del Ferraro1Vincenzo Molinaro2Loredana Zollo3Paolo Lenzuni4Laboratory of Ergonomics and Physiology, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, National Institute for Insurance against Accidents at Work (INAIL), Monte Porzio Catone, ItalyLaboratory of Ergonomics and Physiology, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, National Institute for Insurance against Accidents at Work (INAIL), Monte Porzio Catone, ItalyLaboratory of Ergonomics and Physiology, Department of Occupational and Environmental Medicine, Epidemiology and Hygiene, National Institute for Insurance against Accidents at Work (INAIL), Monte Porzio Catone, ItalyUnit of Advanced Robotics and Human-Centred Technologies, Campus Bio-Medico University of Rome, Rome, ItalyTuscany Regional Research Center, National Institute for Insurance against Accidents at Work (INAIL), Florence, ItalyIntroductionEarly identification of hypothermia or hyperthermia is of vital importance, and real-time monitoring of core temperature (CT) of the workers exposed to thermal environments is an extremely valuable tool. From the existing literature studies, the model developed by Buller et al. in their study of 2013 that generates real-time estimates of CT from heart rate (HR) measurements using the Kalman filter (KF) shows good potential for occupational application. However, some aspects could be improved to reliably handle the existing very wide range of workers and work activities. This study presents a real-time CT estimation model, called the Biphasic Kalman filter-based (BKFB) model, based on HR measurement, with characteristics suited to application in the occupational field.MethodsThirteen healthy subjects (six female and seven male) were included in the study to perform three consecutive tasks simulating work activities. During each test, an ingestible CT sensor was used to measure CT and a HR sensor to measure HR. The KF methodology was used to develop the BKFB model.ResultsAn algorithm with a biphasic structure was developed using two different models for the increasing and decreasing phases of CT, with the ability to switch between the two based on an HR threshold. CT estimates were compared with CT measurements, and with respect to overall root mean square error (RMSE), the BKFB model achieved a sizeable reduction (0.28 ± 0.12°C) compared to the Buller et al. model (0.34 ± 0.16°C).DiscussionThe BKFB model introduced some modifications over the Buller et al. model for a more effective application in the occupational field. It was developed using data collected from a sample of workers (heavily weighted toward middle-aged, not very fit, and with a considerable fraction of female workers), and it also included two different modeling of CT (for the up- and down-phases), which allowed for better behavioral modeling in the two different stages. The BKFB model provides CT estimates reasonably in comparison to the measured intra-abdominal temperature values in both the activity and recovery phases but is more practical and easier to use for a real-time monitoring system of the workers' thermal states.https://www.frontiersin.org/articles/10.3389/fpubh.2024.1219595/fullhuman core temperaturethermal strainestimation modelswearable devicesoccupational health
spellingShingle Tiziana Falcone
Simona Del Ferraro
Vincenzo Molinaro
Loredana Zollo
Paolo Lenzuni
A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational field
Frontiers in Public Health
human core temperature
thermal strain
estimation models
wearable devices
occupational health
title A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational field
title_full A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational field
title_fullStr A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational field
title_full_unstemmed A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational field
title_short A real-time biphasic Kalman filter-based model for estimating human core temperature from heart rate measurements for application in the occupational field
title_sort real time biphasic kalman filter based model for estimating human core temperature from heart rate measurements for application in the occupational field
topic human core temperature
thermal strain
estimation models
wearable devices
occupational health
url https://www.frontiersin.org/articles/10.3389/fpubh.2024.1219595/full
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