Accuracy of Wearable Devices for Measuring Heart Rate During Conventional and Nordic Walking.
Nordic walking is being used increasingly as an exercise method in many clinical disorders. To apply Nordic walking in cases of fragile or deconditioned patients, monitoring of exercise intensity such as heart rate (HR) measurement is required. The accuracy of wearable HR monitors during Nordic walking has not yet been reported.
To compare the accuracy of an electrocardiography (ECG)-based HR monitor (Polar H7) and a photoplethysmography (PPG)-based HR monitor (Fitbit Charge 2) during conventional and Nordic walking.
Accuracy was assessed by comparing the HR values obtained using the wearable devices with those obtained via 12-lead ECG as a reference.
Laboratory setting.
Fifteen male volunteers age 23.7 ± 3.0 years.
None.
HR was simultaneously recorded via 12-lead ECG, the Polar H7, and the Fitbit Charge 2 during conventional and Nordic walking. Agreement between the devices was assessed by calculating Lin's concordance correlation coefficient (rc ), the mean absolute difference, and the limit of agreement (LoA) from Bland-Altman plots.
Regarding HR values including Nordic and conventional walking, there was a better agreement between the Polar H7 and the reference (rc = 0.96) than between the Fitbit Charge 2 and the reference (rc = 0.84). For the Polar H7, the mean absolute difference from the reference did not differ significantly between the walking methods; for the Fitbit Charge 2, the mean absolute difference was significantly higher during Nordic walking than during conventional walking (6.60 vs. 3.68 bpm, P < .001). The Fitbit Charge 2 had a wider LoA than did the Polar H7 during both walking methods.
ECG-based wearable devices may be better than PPG-based devices for monitoring HR during Nordic walking. However, both types of devices may adequately monitor HR during conventional walking.
Baek S
,Ha Y
,Park HW
《-》
Accuracy of Consumer Wearable Heart Rate Measurement During an Ecologically Valid 24-Hour Period: Intraindividual Validation Study.
Wrist-worn smart watches and fitness monitors (ie, wearables) have become widely adopted by consumers and are gaining increased attention from researchers for their potential contribution to naturalistic digital measurement of health in a scalable, mobile, and unobtrusive way. Various studies have examined the accuracy of these devices in controlled laboratory settings (eg, treadmill and stationary bike); however, no studies have investigated the heart rate accuracy of wearables during a continuous and ecologically valid 24-hour period of actual consumer device use conditions.
The aim of this study was to determine the heart rate accuracy of 2 popular wearable devices, the Apple Watch 3 and Fitbit Charge 2, as compared with the gold standard reference method, an ambulatory electrocardiogram (ECG), during consumer device use conditions in an individual. Data were collected across 5 daily conditions, including sitting, walking, running, activities of daily living (ADL; eg, chores, brushing teeth), and sleeping.
One participant, (first author; 29-year-old Caucasian male) completed a 24-hour ecologically valid protocol by wearing 2 popular wrist wearable devices (Apple Watch 3 and Fitbit Charge 2). In addition, an ambulatory ECG (Vrije Universiteit Ambulatory Monitoring System) was used as the gold standard reference method, which resulted in the collection of 102,740 individual heartbeats. A single-subject design was used to keep all variables constant except for wearable devices while providing a rapid response design to provide initial assessment of wearable accuracy for allowing the research cycle to keep pace with technological advancements. Accuracy of these devices compared with the gold standard ECG was assessed using mean error, mean absolute error, and mean absolute percent error. These data were supplemented with Bland-Altman analyses and concordance class correlation to assess agreement between devices.
The Apple Watch 3 and Fitbit Charge 2 were generally highly accurate across the 24-hour condition. Specifically, the Apple Watch 3 had a mean difference of -1.80 beats per minute (bpm), a mean absolute error percent of 5.86%, and a mean agreement of 95% when compared with the ECG across 24 hours. The Fitbit Charge 2 had a mean difference of -3.47 bpm, a mean absolute error of 5.96%, and a mean agreement of 91% when compared with the ECG across 24 hours. These findings varied by condition.
The Apple Watch 3 and the Fitbit Charge 2 provided acceptable heart rate accuracy (<±10%) across the 24 hour and during each activity, except for the Apple Watch 3 during the daily activities condition. Overall, these findings provide preliminary support that these devices appear to be useful for implementing ambulatory measurement of cardiac activity in research studies, especially those where the specific advantages of these methods (eg, scalability, low participant burden) are particularly suited to the population or research question.
Nelson BW
,Allen NB
《JMIR mHealth and uHealth》
Measurement of Heart Rate Using the Polar OH1 and Fitbit Charge 3 Wearable Devices in Healthy Adults During Light, Moderate, Vigorous, and Sprint-Based Exercise: Validation Study.
Accurate, continuous heart rate measurements are important for health assessment, physical activity, and sporting performance, and the integration of heart rate measurements into wearable devices has extended its accessibility. Although the use of photoplethysmography technology is not new, the available data relating to the validity of measurement are limited, and the range of activities being performed is often restricted to one exercise domain and/or limited intensities.
The primary objective of this study was to assess the validity of the Polar OH1 and Fitbit Charge 3 devices for measuring heart rate during rest, light, moderate, vigorous, and sprint-type exercise.
A total of 20 healthy adults (9 female; height: mean 1.73 [SD 0.1] m; body mass: mean 71.6 [SD 11.0] kg; and age: mean 40 [SD 10] years) volunteered and provided written informed consent to participate in the study consisting of 2 trials. Trial 1 was split into 3 components: 15-minute sedentary activities, 10-minute cycling on a bicycle ergometer, and incremental exercise test to exhaustion on a motorized treadmill (18-42 minutes). Trial 2 was split into 2 components: 4 × 15-second maximal sprints on a cycle ergometer and 4 × 30- to 50-m sprints on a nonmotorized resistance treadmill. Data from the 3 devices were time-aligned, and the validity of Polar OH1 and Fitbit Charge 3 was assessed against Polar H10 (criterion device). Validity was evaluated using the Bland and Altman analysis, Pearson moment correlation coefficient, and mean absolute percentage error.
Overall, there was a very good correlation between the Polar OH1 and Polar H10 devices (r=0.95), with a mean bias of -1 beats·min-1 and limits of agreement of -20 to 19 beats·min-1. The Fitbit Charge 3 device underestimated heart rate by 7 beats·min-1 compared with Polar H10, with a limit of agreement of -46 to 33 beats·min-1 and poor correlation (r=0.8). The mean absolute percentage error for both devices was deemed acceptable (<5%). Polar OH1 performed well across each phase of trial 1; however, validity was worse for trial 2 activities. Fitbit Charge 3 performed well only during rest and nonsprint-based treadmill activities.
Compared with our criterion device, Polar OH1 was accurate at assessing heart rate, but the accuracy of Fitbit Charge 3 was generally poor. Polar OH1 performed worse during trial 2 compared with the activities in trial 1, and the validity of the Fitbit Charge 3 device was particularly poor during our cycling exercises.
Muggeridge DJ
,Hickson K
,Davies AV
,Giggins OM
,Megson IL
,Gorely T
,Crabtree DR
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《JMIR mHealth and uHealth》