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American Journal of Respiratory and... Jul 2021
Topics: Biomarkers; Cardiovascular Diseases; Heart Rate; Humans; Polysomnography; Sleep Apnea Syndromes
PubMed: 33915067
DOI: 10.1164/rccm.202102-0512LE -
Scientific Reports Jan 2020Availability of daily continuous blood pressure (DCBP) has a strong impact to realization of healthy society. However, existing methods to obtain blood pressure of cuff... (Observational Study)
Observational Study
Availability of daily continuous blood pressure (DCBP) has a strong impact to realization of healthy society. However, existing methods to obtain blood pressure of cuff type and cuff-less types utilizing correlation with pulse waveform, pulse transit time or pulse rate; or computation of circulation model are not suitable to obtain DCBP. Here we implemented a method based on a simple circulatory system model using pulse rate measurement to overcome the limitations, and showed that it provides appropriate estimation of DCBP. The present model consists of a circulatory dynamic system model and an inverse model of a circulatory control system with input of pulse rate and six model parameters representing standard pulse rate, elasticity of systemic arteries, peripheral vascular resistance, and characteristics of resistance and stroke volume control. Validity of the DCBP estimation method was examined by preliminary experiment for one subject in four days and that for four subjects in one day. DCBP estimation was performed with 24-hour pulse rate measurement by a wearable device and sphygmomanometer measurement for parameter determination and verification. Mean absolute errors in systolic/diastolic pressures were appropriate ones for preliminary experiments with 9.4/6.4 mmHg in four days and 7.3/5.9 mmHg in five subjects.
Topics: Adult; Blood Pressure; Blood Pressure Monitoring, Ambulatory; Blood Pressure Monitors; Healthy Volunteers; Heart Rate; Humans; Male; Middle Aged; Models, Cardiovascular; Stroke Volume; Vascular Resistance; Wearable Electronic Devices; Young Adult
PubMed: 31996723
DOI: 10.1038/s41598-020-58367-y -
Sensors (Basel, Switzerland) Aug 2022The paper presents a wearable sensor for breath and pulse monitoring using an inertial sensor and episodic broadcast radio transmission. The data transmission control...
The paper presents a wearable sensor for breath and pulse monitoring using an inertial sensor and episodic broadcast radio transmission. The data transmission control algorithm applied allows for the transmission of additional information using the standard PDU format and, at the same time, goes beyond the Bluetooth teletransmission standard (BLE). The episodic broadcast transmission makes it possible to receive information from sensors without the need to create a dedicated radio link or a defined network structure. The radio transmission controlled by the occurrence of a specific event in the monitored signal is combined with the reference wire transmission. The signals from two different types of sensors and the simulated ECG signal are used to control the BLE transmission. The presented results of laboratory tests indicate the effectiveness of episodic data transmission in the BLE standard. The conducted analysis showed that the mean difference in pulse detection using the episodic transmission compared to the wire transmission is 0.038 s, which is about 4% of the mean duration of a single cycle, assuming that the average adult human pulse is 60 BPM.
Topics: Adult; Algorithms; Heart Rate; Humans; Monitoring, Physiologic; Respiration
PubMed: 36015777
DOI: 10.3390/s22166019 -
Computer Methods and Programs in... Jun 2022Consumer-level cameras have provided an advantage of designing cost-effective, non-contact physiological parameters estimation approaches which is not possible with gold... (Review)
Review
BACKGROUND
Consumer-level cameras have provided an advantage of designing cost-effective, non-contact physiological parameters estimation approaches which is not possible with gold standard estimation techniques. This encourages the development of non-contact estimation methods using camera technology. Therefore, this work aims to present a systematic review summarizing the currently existing face-based non-contact methods along with their performance.
METHODS
This review includes all heart rate (HR) and oxygen saturation (SpO2) studies published in journals and a few reputed conferences, which have compared the proposed estimation methods with one or more standard reference devices. The articles were collected from the following research databases: Institute of Electrical and Electronics Engineers (IEEE), PubMed, Web of Science (WoS), Science Direct, and Association of Computer Machinery (ACM) digital library. All database searches were completed on May 20, 2021. Each study was assessed using a finite set of identified factors for reporting bias.
RESULTS
Out of 332 identified studies, 32 studies were selected for the final review. Additionally, 18 studies were included by thoroughly checking these studies. 3 out of 50 (6%) studies were performed in clinical conditions, while the remaining studies were carried out on a healthy population. 42 out of 50 (84%) studies have estimated HR, while 5/50 (10%) studies have measured SpO only. The remaining three studies have estimated both parameters. The majority of the studies have used 1-3 min videos for estimation. Among the estimation methods, Deep Learning and Independent component analysis (ICA) were used by 11/42 (26.19%) and 9/42 (21.42%) studies, respectively. According to the Bland-Altman analysis, only 8/45 (17.77%) HR studies achieved the clinically accepted error limits whereas, for SpO, 4/5 (80%) studies have matched the industry standards (±3%).
DISCUSSION
Deep Learning and ICA have been predominantly used for HR estimations. Among deep learning estimation methods, convolutional neural networks have been employed till date due to their good generalization ability. Most non-contact HR estimation methods need significant improvements to implement these methods in a clinical environment. Furthermore, these methods need to be tested on the subjects suffering from any related disease. SpO estimation studies are challenging and need to be tested by conducting hypoxemic events. The authors would encourage reporting the detailed information about the study population, the use of longer videos, and appropriate performance metrics and testing under abnormal HR and SpO ranges for future estimation studies.
Topics: Face; Heart Rate; Humans; Oxygen Saturation
PubMed: 35390724
DOI: 10.1016/j.cmpb.2022.106771 -
Nihon Eiseigaku Zasshi. Japanese... 2014There has been growing attention on the effects of forest on physiological relaxation and immune recovery, particularly in forest medicine research, from a perspective... (Review)
Review
There has been growing attention on the effects of forest on physiological relaxation and immune recovery, particularly in forest medicine research, from a perspective of preventive medicine. Japan is a world leader in the accumulation of scientific data on forest medicine research. In this review, we summarize the research that has been conducted in this area since 1992. We conducted field experiment, involving 420 subjects at 35 different forests throughout Japan. After sitting in natural surroundings, these subjects showed decrease in the following physiological parameters compared with those in an urban control group: 12.4% decrease in the cortisol level, 7.0% decrease in sympathetic nervous activity, 1.4% decrease in systolic blood pressure, and 5.8% decrease in heart rate. This demonstrates that stressful states can be relieved by forest therapy. In addition, it should be noted that parasympathetic nervous activity was enhanced by 55.0%, indicating a relaxed state. The results of walking experiments provided similar results. Li et al. demonstrated that immune function was enhanced by forest therapy in middle-aged employees who volunteered to participate in these experiments. Natural killer cell activity, an indicator of immune function, was enhanced by 56% on the second day and returned to normal levels. A significant increase of 23% was maintained for 1 month even after returning to urban life, clearly illustrating the preventive benefits of forest therapy. In an indoor room experiment, we conducted tests with the following: 1) olfactory stimulation using wood smell, 2) tactile stimulation using wood, and 3) auditory stimulation using forest sounds. These indoor stimulations also decreased the blood pressure and pulse rate, and induced a physiological relaxation effect. We anticipate that forest medicine will play an increasingly important role in preventive medicine in the future.
Topics: Blood Pressure; Forests; Heart Rate; Humans; Japan; Relaxation Therapy; Stress, Psychological; Walking
PubMed: 24858508
DOI: 10.1265/jjh.69.122 -
Sensors (Basel, Switzerland) Oct 2022With the recent advancements in the field of wearable technologies, the opportunity to monitor stress continuously using different physiological variables has gained...
With the recent advancements in the field of wearable technologies, the opportunity to monitor stress continuously using different physiological variables has gained significant interest. The early detection of stress can help improve healthcare and minimizes the negative impact of long-term stress. This paper reports outcomes of a pilot study and associated stress-monitoring dataset, named the "Stress-Predict Dataset", created by collecting physiological signals from healthy subjects using wrist-worn watches with a photoplethysmogram (PPG) sensor. While wearing these watches, 35 healthy volunteers underwent a series of tasks (i.e., Stroop color test, Trier Social Stress Test and Hyperventilation Provocation Test), along with a rest period in-between each task. They also answered questionnaires designed to induce stress levels compatible with daily life. The changes in the blood volume pulse (BVP) and heart rate were recorded by the watch and were labelled as occurring during stress-inducing tasks or a rest period (no stress). Additionally, respiratory rate was estimated using the BVP signal. Statistical models and personalised adaptive reference ranges were used to determine the utility of the proposed stressors and the extracted variables (heart rate and respiratory rate). The analysis showed that the interview session was the most significant stress stimulus, causing a significant variation in heart rate of 27 (77%) participants and respiratory rate of 28 (80%) participants out of 35. The outcomes of this study contribute to the understanding the role of stressors and their association with physiological response and provide a dataset to help develop new wearable solutions for more reliable, valid, and sensitive physio-logical stress monitoring.
Topics: Humans; Pilot Projects; Wearable Electronic Devices; Heart Rate; Monitoring, Physiologic; Respiratory Rate; Photoplethysmography
PubMed: 36365837
DOI: 10.3390/s22218135 -
American Journal of Hypertension Aug 2013Debate exists about the relationship between hypovitaminosis D and cardiovascular (CVD) risk.
BACKGROUND
Debate exists about the relationship between hypovitaminosis D and cardiovascular (CVD) risk.
METHODS
This study investigated baseline (n=2,271) 25-hydroxyvitamin D (25(OH)D) and baseline and 4 year (n=1,957) CVD risk in a cohort of Finnish middle-aged male smokers.
RESULTS
The prevalences of measured hypertension, high pulse rate, diabetes, and coronary heart disease were 63%, 16%, 5%, and 10% at baseline and were 64%, 20%, 6%, and 16% at 4 years after baseline. The mean 25(OH)D was 41±18 nmol/L. At baseline, systolic blood pressure (β = -0.048; P = 0.02), and pulse rate (β = -0.043; P = 0.04) were both associated with lower 25(OH)D levels but not coronary heart disease or diabetes prevalence. On remeasuring CVD risk 4 years after baseline, the only significant association with baseline 25(OH)D levels was high pulse rate (β = -0.077; P = 0.001). In addition, a higher 25(OH)D level at baseline was associated with a change in pulse rate (β = -0.055; P = 0.01). These trends for hypertension (baseline) and high pulse rate (baseline and 4 years after baseline) were also seen on adjusted categorical analysis (P trend < 0.05).
CONCLUSIONS
Vitamin D deficiency at baseline was associated with hypertension in Finnish male smokers, but not after 4 years. These results are consistent with recent findings in other large cohort studies with measured blood pressure. Change in pulse rate over time continued to be significantly associated with lower 25(OH)D baseline levels; this new finding should be investigated further.
Topics: Aged; Cardiovascular Diseases; Cohort Studies; Coronary Disease; Diabetes Mellitus; Finland; Heart Rate; Humans; Hypertension; Linear Models; Longitudinal Studies; Male; Middle Aged; Risk Factors; Smoking; Vitamin D; Vitamin D Deficiency
PubMed: 23598420
DOI: 10.1093/ajh/hpt051 -
Sensors (Basel, Switzerland) Aug 2021Alterations of heart rate variability (HRV) are associated with various (patho)physiological conditions; therefore, HRV analysis has the potential to become a useful...
Alterations of heart rate variability (HRV) are associated with various (patho)physiological conditions; therefore, HRV analysis has the potential to become a useful diagnostic module of wearable/telemedical devices to support remote cardiovascular/autonomic monitoring. Continuous pulse recordings obtained by photoplethysmography (PPG) can yield pulse rate variability (PRV) indices similar to HRV parameters; however, it is debated whether PRV/HRV parameters are interchangeable. In this study, we assessed the PRV analysis module of a digital arterial PPG-based telemedical system (SCN4ALL). We used Bland-Altman analysis to validate the SCN4ALL PRV algorithm to Kubios Premium software and to determine the agreements between PRV/HRV results calculated from 2-min long PPG and ECG captures recorded simultaneously in healthy individuals (n = 33) at rest and during the cold pressor test, and in diabetic patients (n = 12) at rest. We found an ideal agreement between SCN4ALL and Kubios outputs (bias < 2%). PRV and HRV parameters showed good agreements for interbeat intervals, SDNN, and RMSSD time-domain variables, for total spectral and low-frequency power (LF) frequency-domain variables, and for non-linear parameters in healthy subjects at rest and during cold pressor challenge. In diabetics, good agreements were observed for SDNN, LF, and SD2; and moderate agreement was observed for total power. In conclusion, the SCN4ALL PRV analysis module is a good alternative for HRV analysis for numerous conventional HRV parameters.
Topics: Autonomic Nervous System; Electrocardiography; Heart Rate; Humans; Photoplethysmography; Telemedicine
PubMed: 34450986
DOI: 10.3390/s21165544 -
Computers in Biology and Medicine Dec 2022Data-based approaches promise to use the information in cardiovascular signals to diagnose cardiovascular diseases. Considerable effort has been undertaken in the field...
BACKGROUND
Data-based approaches promise to use the information in cardiovascular signals to diagnose cardiovascular diseases. Considerable effort has been undertaken in the field of pulse-wave analysis to harness this information. However, the inverse problem, inferring arterial properties from waveform measurements, is not well understood today. Consequently, uncertainties within the estimation hinder the diagnostic application of such methods.
METHOD
This work contributes a publicly available data set measured at an in-vitro cardiovascular simulator, focusing on a set of input conditions (heart rate, waveform) and stenosis locations. Furthermore, a first attempt is undertaken to perform classification and regression on this data set using standard machine learning methods on features extracted from four peripheral pressure signals.
RESULTS
The locations of six different stenoses could be distinguished at high accuracy of 93%, where transfer function-based features outperformed features based solely on signal shape in almost all cases. Furthermore, regression on the stenosis position could be performed with a root mean square error of 2.4 cm along a 20 cm section of the arterial system using a shallow neural network. However, the performance difference between shape and transfer function features was not clear for this task.
CONCLUSION
The data set contains 800 measurements and allows investigating the influence of different heart boundary conditions, such as heart rate and waveform shape, on classification and regression tasks. Extracting features that minimise this influence is a promising way of improving the performance of these tasks.
Topics: Humans; Heart Rate; Constriction, Pathologic; Pulse Wave Analysis; Neural Networks, Computer; Arteries; Blood Pressure
PubMed: 36327886
DOI: 10.1016/j.compbiomed.2022.106224 -
American Heart Journal Oct 2014Elevated resting pulse rate (RPR) is a well-recognized risk factor for adverse outcomes. Epidemiological evidence supports the beneficial effects of regular exercise for... (Randomized Controlled Trial)
Randomized Controlled Trial
BACKGROUND
Elevated resting pulse rate (RPR) is a well-recognized risk factor for adverse outcomes. Epidemiological evidence supports the beneficial effects of regular exercise for lowering RPR, but studies are mainly confined to persons younger than 65 years. We set out to evaluate the utility of a physical activity (PA) intervention for slowing RPR among older adults.
METHODS
A total of 424 seniors (ages 70-89 years) were randomized to a moderate intensity PA intervention or an education-based "successful aging" health program. Resting pulse rate was assessed at baseline, 6 months, and 12 months. Longitudinal differences in RPR were evaluated between treatment groups using generalized estimating equation models, reporting unstandardized β coefficients with robust SEs.
RESULTS
Increased frequency and duration of aerobic training were observed for the PA group at 6 and 12 months as compared with the successful aging group (P < .001). In both groups, RPR remained unchanged over the course of the 12-month study period (P = .67). No significant improvement was observed (β [SE] = 0.58 [0.88]; P = .51) for RPR when treatment groups were compared using the generalized estimating equation method. Comparable results were found after omitting participants with a pacemaker, cardiac arrhythmia, or who were receiving β-blockers.
CONCLUSIONS
Twelve months of moderate intensity aerobic training did not improve RPR among older adults. Additional studies are needed to determine whether PA of longer duration and/or greater intensity can slow RPR in older persons.
Topics: Age Factors; Aged; Aged, 80 and over; Cardiovascular Diseases; Exercise Therapy; Female; Heart Rate; Humans; Incidence; Male; Motor Activity; Prognosis; Rest; Single-Blind Method; United States
PubMed: 25262271
DOI: 10.1016/j.ahj.2014.07.024