Fitbit Charge HR Wireless Heart Rate Monitor: Validation Study Conducted Under Free-Living Conditions

Background: Many modern smart watches and activity trackers feature an optical sensor that estimates the wearer’s heart rate. Recent studies have evaluated the performance of these consumer devices in the laboratory. Objective: The objective of our study was to examine the accuracy and sensitivity of a common wrist-worn tracker device in measuring heart rates and detecting 1-min bouts of moderate to vigorous physical activity (MVPA) under free-living conditions. Methods: Ten healthy volunteers were recruited from a large university in Singapore to participate in a limited field test, followed by a month of continuous data collection. During the field test, each participant would wear one Fitbit Charge HR activity tracker and one Polar H6 heart rate monitor. Fitbit measures were accessed at 1-min intervals, while Polar readings were available for 10-s intervals. We derived intraclass correlation coefficients (ICCs) for individual participants comparing heart rate estimates. We applied Centers for Disease Control and Prevention heart rate zone cut-offs to ascertain the sensitivity and specificity of Fitbit in identifying 1-min epochs falling into MVPA heart rate zone. Results: We collected paired heart rate data for 2509 1-min epochs in 10 individuals under free-living conditions of 3 to 6 hours. The overall ICC comparing 1-min Fitbit measures with average 10-s Polar H6 measures for the same epoch was .83 (95% CI .63-.91). On average, the Fitbit tracker underestimated heart rate measures by −5.96 bpm (standard error, SE=0.18). At the low intensity heart rate zone, the underestimate was smaller at −4.22 bpm (SE=0.15). This underestimate grew to −16.2 bpm (SE=0.74) in the MVPA heart rate zone. Fitbit devices detected 52.9% (192/363) of MVPA heart rate zone epochs correctly. Positive and negative predictive values were 86.1% (192/223) and 92.52% (2115/2286), respectively. During subsequent 1 month of continuous data collection (270 person-days), only 3.9% of 1-min epochs could be categorized as MVPA according to heart rate zones. This measure was affected by decreasing wear time and adherence over the period of follow-up. Conclusions: Under free-living conditions, Fitbit trackers are affected by significant systematic errors. Improvements in tracker accuracy and sensitivity when measuring MVPA are required before they can be considered for use in the context of exercise prescription to promote better health

Acoustically based fetal heart rate monitor

The acoustically based fetal heart rate monitor permits an expectant mother to perform the fetal Non-Stress Test in her home. The potential market would include the one million U.S. pregnancies per year requiring this type of prenatal surveillance. The monitor uses polyvinylidene fluoride (PVF2) piezoelectric polymer film for the acoustic sensors, which are mounted in a seven-element array on a cummerbund. Evaluation of the sensor ouput signals utilizes a digital signal processor, which performs a linear prediction routine in real time. Clinical tests reveal that the acoustically based monitor provides Non-Stress Test records which are comparable to those obtained with a commercial ultrasonic transducer

Relationships Among Heart Rate Monitor Usage, Neuroticism, and Performance in Triathletes

Triathlon, a sport that consists of swimming, biking and running, is growing in popularity throughout the country and the world. There is a large percentage of athletes that rely on the use of a heart rate monitor to gauge effort, but there is also a group of athletes that do not use this technology. The purpose of this research was to determine if personality, specifically neuroticism, played a role in determining which athletes use heart rate monitors and whether these variables had any effect on performance. Ninety-eight triathletes were surveyed from 2 half iron distance triathlons in the summer of 2010. There proved to be no interaction effect between neuroticism and heart rate monitor usage on performance [F 2 = 1.830, p = 0.168]. Interestingly, the data showed that there was no significant relationship between heart rate monitor usage and performance. This finding is interesting because heart rate monitors are widely used in the triathlon community, and these data show that perhaps heart rate monitors are not the best tool for gauging effort

Algorithm for heart rate extraction in a novel wearable acoustic sensor.

Phonocardiography is a widely used method of listening to the heart sounds and indicating the presence of cardiac abnormalities. Each heart cycle consists of two major sounds - S1 and S2 - that can be used to determine the heart rate. The conventional method of acoustic signal acquisition involves placing the sound sensor at the chest where this sound is most audible. Presented is a novel algorithm for the detection of S1 and S2 heart sounds and the use of them to extract the heart rate from signals acquired by a small sensor placed at the neck. This algorithm achieves an accuracy of 90.73 and 90.69%, with respect to heart rate value provided by two commercial devices, evaluated on more than 38 h of data acquired from ten different subjects during sleep in a pilot clinical study. This is the largest dataset for acoustic heart sound classification and heart rate extraction in the literature to date. The algorithm in this study used signals from a sensor designed to monitor breathing. This shows that the same sensor and signal can be used to monitor both breathing and heart rate, making it highly useful for long-term wearable vital signs monitoring

HEART RATE MONITOR USING INFRARED

The heart rate is one of the significant physiological parameters of the human cardiovascular system. Heart rate is the number of times the heart beats per minute. Heart rate data reflects various physiological states such as biological workload,stress at work and concentration on tasks, drowsiness and the active state of the autonomic nervous system. Human cardiac dynamics are driven by the complex nonlinear interactions of two competing forces: sympathetic regulation increases and parasympathetic regulation decreases the heart rate. Thus,monitoring of heart rate plays a significant role in providing the status of cardiovascular system and clinically correlated information to medical professionals. Heart rate measurement is also regarded as an essential parameter in patient care monitoring system. Heart rate can be measured either by the ECG waveform or by sensing the pulse - the rhythmic expansion and contraction of an artery as blood is forced through it by the regular contractions of the heart. The pulse can be felt from those areas where the artery is close to the skin. This paper highlights on the design of a microcontroller (PIC series) based heart rate counter that is able to capture the pulse from finger tip by sensing the change in blood volume. The heart rates of fifteen healthy normal subjects (students of age 21-22 yrs.) both in relaxed and excited states were measured using the designed device and a standard heart rate measuring device. The outputs of the measured device were satisfactory. Also, the designed device,being noninvasive one, can easily find its place in health care monitoring system

Radiotelemetry Of Heart Rates From Free-Ranging Gulls

A lightweight radiotelemetry system with a range of 80 km was used to monitor heart rate from free-ranging Herring Gulls on flights of up to 20 km. Heart rate varied from 130 beats/min in a resting bird to 625 beats/min for sustained flight. Soaring birds showed rates similar to those of birds sitting quietly on the ground. Simultaneous records of telemetered heart rate and intraspecific conflict on the nesting island revealed that cardiac acceleration preceded overt visual communication. Intensely aggressive behavior was accompanied by heart rates approaching those of sustained flight. Heart rate as a measure of metabolic cost indicates that the gull\u27s behavioral adaptations for long-distance flight, food location and intraspecific communication result in major energy savings

Signal processing methodologies for an acoustic fetal heart rate monitor

Research and development is presented of real time signal processing methodologies for the detection of fetal heart tones within a noise-contaminated signal from a passive acoustic sensor. A linear predictor algorithm is utilized for detection of the heart tone event and additional processing derives heart rate. The linear predictor is adaptively 'trained' in a least mean square error sense on generic fetal heart tones recorded from patients. A real time monitor system is described which outputs to a strip chart recorder for plotting the time history of the fetal heart rate. The system is validated in the context of the fetal nonstress test. Comparisons are made with ultrasonic nonstress tests on a series of patients. Comparative data provides favorable indications of the feasibility of the acoustic monitor for clinical use

Intelligent Pillow for Heart Rate Monitor

The aim of the project is to develop intelligent pillow to monitor the heart rate by using fiber optical sensor. The research is focused upon allowing more automation of patient care, an especially important matter for the elder population or bedridden patients, which is a rapidly growing fraction of much of the world population today. The fiber-optical sensor is built into pillow. Patients can determine their heart rate by just lying on the pillow and the device will not cause any disturbance to patients and at the same time still monitoring the heart rate. ECG electrodes and finger clip / ear lobe clip probes (using IR LED and photodiode technology) are commonly used for monitoring heart rate. Unfortunately, they are inconvenient and inadequate for long-term, everyday measurements. Fiber-optical sensing overcomes many of these challenges by using light rather than electricity and standard optical fiber in place of copper wire. Optical fibers are nonconductive, electrically passive, immune to electromagnetic interference (EMI)-induced noise, and able to transmit data over long distances with little or no loss in signal integrity. Using the concept of light and the benefits of using fiber optical sensors to detect the heart rate, PPG(photoplethysmogram) is being used in this project. A photoplethysmogram (PPG) is an optically obtained plethysmogram, a volumetric measurement of an organ. A PPG is often obtained by using a pulse oximeter which illuminates the skin and measures changes in light absorption (Shelley and Shelley, 2001).DOI:http://dx.doi.org/10.11591/ijece.v3i6.405

Validity of Freely Available Mobile Applications for Recording Resting Heart Rate

This study examined the accuracy of mobile applications that measure heart rate by comparing results to a Polar heart rate monitor. Volunteers had their heart rate measured via four different methods whilst being simultaneously recorded with the Polar monitor; 1) manual (MAN), 2) Tap the Pulse (TAP), 3) Cardiio (CAR), 4) What’s my Heart Rate (WMHR). There were no significant differences between any of the methods and Polar monitor (p ≥ 0.159), with WMHR having the strongest relationship (r2 = 0.918) followed by MAN (r2 = 0.851), CAR (r2 = 0.646) andTAP (r2 = 0.636) respectively