scholarly journals Estimating Resting Core Temperature Using Heart Rate

2018 ◽  
Vol 1 (2) ◽  
pp. 79-86 ◽  
Author(s):  
David P. Looney ◽  
Mark J. Buller ◽  
Andrei V. Gribok ◽  
Jayme L. Leger ◽  
Adam W. Potter ◽  
...  
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Estimation Algorithm ◽  
Quadratic Equation ◽  
Estimation Accuracy ◽  
Future Research ◽  
Accuracy And Precision ◽  
Military Populations ◽  
Thermal Work ◽  
Ct Data

ECTemp™ is a heart rate (HR)-based core temperature (CT) estimation algorithm mainly used as a real-time thermal-work strain indicator in military populations. ECTemp™ may also be valuable for resting CT estimation, which is critical for circadian rhythm research. This investigation developed and incorporated a sigmoid equation into ECTemp™ to better estimate resting CT. HR and CT data were collected over two calorimeter test trials from 16 volunteers (age, 23 ± 3 yrs; height, 1.72 ± 0.07 m; body mass, 68.5 ± 8.1 kg) during periods of sleep and inactivity. Half of the test trials were combined with ECTemp™’s original development dataset to train the new sigmoid model while the other was used for model validation. Models were compared by their estimation accuracy and precision. While both models produced accurate CT estimates, the sigmoid model had a smaller bias (−0.04 ± 0.26°C vs. −0.19 ± 0.29°C) and root mean square error (RMSE; 0.26°C vs. 0.35°C). ECTemp™ is a validated HR-based resting CT estimation algorithm. The new sigmoid equation corrects lower CT estimates while producing nearly identical estimates to the original quadratic equation at higher CT. The demonstrated accuracy of ECTemp™ encourages future research to explore the algorithm’s potential as a non-invasive means of tracking CT circadian rhythms.

scholarly journals Wearable physiological monitoring for human thermal-work strain optimization

2018 ◽  
Vol 124 (2) ◽  
pp. 432-441 ◽  
Author(s):  
Mark J. Buller ◽  
Alexander P. Welles ◽  
Karl E. Friedl
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Health Care Providers ◽  
Military Training ◽  
Computational Techniques ◽  
Care Providers ◽  
Work Intensity ◽  
Physiological Strain ◽  
Work Strain ◽  
Thermal Work

Safe performance limits of soldiers and athletes have typically relied on predictive work-rest models of ambient conditions, average work intensity, and characteristics of the population. Bioengineering advances in noninvasive sensor technologies, including miniaturization, reduced cost, power requirements, and comfort, now make it possible to produce individual predictions of safe thermal-work limits. These precision medicine assessments depend on the development of thoughtful algorithms based on physics and physiology. Both physiological telemetry and thermal-strain indexes have been available for >50 years, but greater computing power and better wearable sensors now make it possible to provide actionable information at the individual level. Core temperature can be practically estimated from time series heart rate data and, using an adaptive physiological strain index, provides meaningful predictions of safe work limits that cannot be predicted from only core temperature or heart rate measurements. Early adopters of this technology include specialized occupations where individuals operate in complete encapsulation such as chemical protective suits. Emerging technologies that focus on heat flux measurements at the skin show even greater potential for estimating thermal-work strain using a parsimonious sensor set. Applications of these wearable technologies include many sports and military training venues where inexperienced individuals can learn effective work pacing strategies and train to safe personal limits. The same strategies can also provide a technologically based performance edge for experienced workers and athletes faced with novel and nonintuitive physiological challenges, such as health care providers in full protective clothing treating Ebola patients in West Africa in 2014. NEW & NOTEWORTHY This mini-review details how the application of computational techniques borrowed from signal processing and control theory can provide meaningful advances for the applied physiological problem of real-time thermal-work strain monitoring. The work examines the development of practical core body temperature estimation techniques and how these can be used in combination with current and updated thermal-work strain indexes to provide objective state assessments and to optimize work rest schedules for a given task.

scholarly journals Non-Invasive Fetal Electrocardiogram Monitoring Techniques: Potential and Future Research Opportunities in Smart Textiles

Signals ◽  
2021 ◽  
Vol 2 (3) ◽  
pp. 392-412
Author(s):  
Geetika Aggarwal ◽  
Yang Wei
Keyword(s):  
Heart Rate ◽  
Fetal Heart Rate ◽  
Fetal Heart ◽  
Skin Penetration ◽  
Future Research ◽  
Fetal Electrocardiogram ◽  
Smart Textiles ◽  
Non Invasive ◽  
Future Research Directions ◽  
Electrocardiogram Monitoring

During the pregnancy, fetal electrocardiogram (FECG) is deployed to analyze fetal heart rate (FHR) of the fetus to indicate the growth and health of the fetus to determine any abnormalities and prevent diseases. The fetal electrocardiogram monitoring can be carried out either invasively by placing the electrodes on the scalp of the fetus, involving the skin penetration and the risk of infection, or non-invasively by recording the fetal heart rate signal from the mother’s abdomen through a placement of electrodes deploying portable, wearable devices. Non-invasive fetal electrocardiogram (NIFECG) is an evolving technology in fetal surveillance because of the comfort to the pregnant women and being achieved remotely, specifically in the unprecedented circumstances such as pandemic or COVID-19. Textiles have been at the heart of human technological progress for thousands of years, with textile developments closely tied to key inventions that have shaped societies. The relatively recent invention of smart textiles is set to push boundaries again and has already opened the potential for garments relevant to medicine, and health monitoring. This paper aims to discuss the different technologies and methods used in non-invasive fetal electrocardiogram (NIFECG) monitoring as well as the potential and future research directions of NIFECG in the smart textiles area.

scholarly journals Novel MARG-Sensor Orientation Estimation Algorithm Using Fast Kalman Filter

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Siwen Guo ◽  
Jin Wu ◽  
Zuocai Wang ◽  
Jide Qian
Keyword(s):  
Kalman Filter ◽  
Process Model ◽  
Attitude Determination ◽  
Angular Rate ◽  
Estimation Algorithm ◽  
Measurement Model ◽  
Estimation Accuracy ◽  
Orientation Estimation ◽  
Kinematic Equation ◽  
Sensor Orientation

Orientation estimation from magnetic, angular rate, and gravity (MARG) sensor array is a key problem in mechatronic-related applications. This paper proposes a new method in which a quaternion-based Kalman filter scheme is designed. The quaternion kinematic equation is employed as the process model. With our previous contributions, we establish the measurement model of attitude quaternion from accelerometer and magnetometer, which is later proved to be the fastest (computationally) one among representative attitude determination algorithms of such sensor combination. Variance analysis is later given enabling the optimal updating of the proposed filter. The algorithm is implemented on real-world hardware where experiments are carried out to reveal the advantages of the proposed method with respect to conventional ones. The proposed approach is also validated on an unmanned aerial vehicle during a real flight. Results show that the proposed one is faster than any other Kalman-based ones and even faster than some complementary ones while the attitude estimation accuracy is maintained.

Hypothalamic paraventricular nucleus is critical for renal vasoconstriction elicited by elevations in body temperature

2008 ◽  
Vol 294 (2) ◽  
pp. F309-F315 ◽  
Author(s):  
Joo Lee Cham ◽  
Emilio Badoer
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Blood Flow ◽  
Renal Blood Flow ◽  
Core Temperature ◽  
Paraventricular Nucleus ◽  
Hypothalamic Paraventricular Nucleus ◽  
Body Core Temperature ◽  
Control Group ◽  
Body Core

Redistribution of blood from the viscera to the peripheral vasculature is the major cardiovascular response designed to restore thermoregulatory homeostasis after an elevation in body core temperature. In this study, we investigated the role of the hypothalamic paraventricular nucleus (PVN) in the reflex decrease in renal blood flow that is induced by hyperthermia, as this brain region is known to play a key role in renal function and may contribute to the central pathways underlying thermoregulatory responses. In anesthetized rats, blood pressure, heart rate, renal blood flow, and tail skin temperature were recorded in response to elevating body core temperature. In the control group, saline was microinjected bilaterally into the PVN; in the second group, muscimol (1 nmol in 100 nl per side) was microinjected to inhibit neuronal activity in the PVN; and in a third group, muscimol was microinjected outside the PVN. Compared with control, microinjection of muscimol into the PVN did not significantly affect the blood pressure or heart rate responses. However, the normal reflex reduction in renal blood flow observed in response to hyperthermia in the control group (∼70% from a resting level of 11.5 ml/min) was abolished by the microinjection of muscimol into the PVN (maximum reduction of 8% from a resting of 9.1 ml/min). This effect was specific to the PVN since microinjection of muscimol outside the PVN did not prevent the normal renal blood flow response. The data suggest that the PVN plays an essential role in the reflex decrease in renal blood flow elicited by hyperthermia.

scholarly journals A Pragmatic Controlled Trial of Forest Bathing Compared with Compassionate Mind Training in the UK: Impacts on Self-Reported Wellbeing and Heart Rate Variability

2021 ◽  
Vol 13 (3) ◽  
pp. 1380
Author(s):  
Kirsten McEwan ◽  
David Giles ◽  
Fiona J. Clarke ◽  
Yasu Kotera ◽  
Gary Evans ◽  
...  
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Positive Emotions ◽  
Controlled Trial ◽  
Healthcare Providers ◽  
Increase Heart Rate ◽  
Future Research ◽  
Post Intervention ◽  
Forest Bathing ◽  
Mind Training

Forest Bathing, where individuals use mindfulness to engage with nature, has been reported to increase heart rate variability and benefit wellbeing. To date, most Forest Bathing studies have been conducted in Asia. Accordingly, this paper reports the first pragmatic controlled trial of Forest Bathing in the United Kingdom, comparing Forest Bathing with a control comprising an established wellbeing intervention also known to increase heart rate variability called Compassionate Mind Training. Sixty-one university staff and students (50 females, 11 males) were allocated to (i) Forest Bathing, (ii) Compassionate Mind Training or (iii) Forest Bathing combined with Compassionate Mind Training. Wellbeing and heart rate variability were measured at baseline, post-intervention and three-months follow-up. There were improvements in positive emotions, mood disturbance, rumination, nature connection and compassion and 57% of participants showed an increase in heart rate variability. There were no significant differences between conditions, showing that Forest Bathing had equivalence with an established wellbeing intervention. The findings will help healthcare providers and policy makers to understand the effects of Forest Bathing and implement it as a feasible social prescription to improve wellbeing. Future research needs to involve clinical populations and to assess the effects of Forest Bathing in a fully powered randomised controlled trial.

scholarly journals Cognitive Performance during a 24-Hour Cold Exposure Survival Simulation

2016 ◽  
Vol 2016 ◽  
pp. 1-11
Author(s):  
Michael J. Taber ◽  
Geoffrey L. Hartley ◽  
Gregory W. McGarr ◽  
Dessi Zaharieva ◽  
Fabien A. Basset ◽  
...  
Keyword(s):  
Cognitive Performance ◽  
Core Temperature ◽  
Cold Exposure ◽  
Ambient Air ◽  
Cognitive Test ◽  
Future Research ◽  
Polar Regions ◽  
Active Engagement ◽  
Metabolic Heat ◽  
Tolerable Level

Survivor of a ship ground in polar regions may have to wait more than five days before being rescued. Therefore, the purpose of this study was to explore cognitive performance during prolonged cold exposure. Core temperature (Tc) and cognitive test battery (CTB) performance data were collected from eight participants during 24 hours of cold exposure (7.5°C ambient air temperature). Participants (recruited from those who have regular occupational exposure to cold) were instructed that they could freely engage in minimal exercise that was perceived to maintaining a tolerable level of thermal comfort. Despite the active engagement, test conditions were sufficient to significantly decreaseTcafter exposure and to eliminate the typical 0.5–1.0°C circadian rise and drop in core temperature throughout a 24 h cycle. Results showed minimal changes in CTB performance regardless of exposure time. Based on the results, it is recommended that survivors who are waiting for rescue should be encouraged to engage in mild physical activity, which could have the benefit of maintaining metabolic heat production, improve motivation, and act as a distractor from cold discomfort. This recommendation should be taken into consideration during future research and when considering guidelines for mandatory survival equipment regarding cognitive performance.

scholarly journals Heart Rate And Core Temperature Responses Of Pit Crew Athletes During Elite Automobile Races.

2009 ◽  
Vol 41 ◽  
pp. 147
Author(s):  
David P. Ferguson ◽  
Trudy L. Moore-Harrison ◽  
Robert S. Bowen ◽  
Katrina J. Hall ◽  
Emily E. Schmitt ◽  
...  
Keyword(s):  
Heart Rate ◽  
Core Temperature ◽  
Temperature Responses

Robust high-degree cubature information filter and its application to trajectory estimation for ballistic missile

2017 ◽  
Vol 232 (12) ◽  
pp. 2364-2377 ◽  
Author(s):  
Xiaogang Wang ◽  
Wutao Qin ◽  
Naigang Cui ◽  
Yu Wang
Keyword(s):  
State Estimation ◽  
Estimation Algorithm ◽  
Ballistic Missile ◽  
Measurement Noise ◽  
Estimation Accuracy ◽  
Trajectory Estimation ◽  
Information Filter ◽  
Non Gaussian ◽  
Time Update ◽  
High Degree

This paper presents a new recursive filter algorithm, the robust high-degree cubature information filter, which can provide reliable state estimation in the presence of non-Gaussian measurement noise. The novel algorithm is developed in the framework of the conventional information filter. The fifth-degree Cubature rule is utilized to improve the estimation accuracy and numerical stability during the time update, while the Huber technique is adopted in the measurements update stage. As the Huber technique is a combined minimum l1 and l2 norm estimation algorithm, the proposed algorithm could exhibit robustness to the non-Gaussian measurement noise, especially the glint noise. In addition, Monte Carlo simulation and the trajectory estimation for ballistic missile experiments demonstrate that the robust high-degree cubature information filter can provide improved state estimation performance over extended information filter and high-degree cubature information filter.

Validation of heart rate measurement of Fitbit Charge 4 and Xiaomi Mi Band 5 (Preprint)

2021 ◽  
Author(s):  
Magdalena Jachymek ◽  
Michał Tomasz Jachymek ◽  
Radosław Marek Kiedrowicz ◽  
Jarosław Kaźmierczak ◽  
Małgorzata Peregud-Pogorzelska
Keyword(s):  
Heart Rate ◽  
Stress Test ◽  
Absolute Error ◽  
Sensor Technology ◽  
Concordance Correlation ◽  
Accuracy And Precision ◽  
Validation Criteria ◽  
Precision And Accuracy ◽  
Fitness Trackers ◽  
Error Percentage

BACKGROUND Recent advances in mobile sensor technology have led to increased popularity of wrist-worn fitness trackers. The possibility to use a smartwatch as a rehabilitation tool to monitor patients’ heart rate during exercise has won the attention of many researchers. OBJECTIVE The aim of the study was to evaluate the accuracy and precision of HR measurement performed by two wrist monitors: Fitbit Charge 4 (Fitbit) and Xiaomi Mi Band 5 (Xiaomi). METHODS 31 healthy volunteers were asked to perform a stress test on a treadmill. During the test their heart rate was recorded simultaneously by both wristbands and ECG at 1minute intervals. The mean absolute error percentage (MAPE), Lin’s concordance correlation coefficient (LCCC) and Bland-Altman were calculated to compare precision and accuracy of heart rate measurements. The estimated validation criteria were MAPE < 10% and LCCC < .8 RESULTS The overall MAPE of the Fitbit device was 10.19% (±11.79%) and the MAPE of Xiaomi was (6.89 % ± 9.75). LCCC of Fitbit HR measurements was .753 (95% CI:0.717-0.785) and of Xiaomi – .903 (0.886-0.917). In both devices the precision and accuracy were decreasing with the increasing exercise intensity. Age, sex, height, weight, BMI did not influence the accuracy of both devices. CONCLUSIONS The accuracy of a wearable wrist-worn heart rate monitor varies and depends on the intensity of training. The decision concerning the application of such a device as a monitor during in-home rehabilitation should be taken with caution, as it may prove not reliable enough.

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