Reliability and Validity of Commercially Available Wearable Devices for Measuring Steps, Energy Expenditure, and Heart Rate: Systematic Review

Abstract

Background Consumer-wearable activity trackers are small electronic devices that record fitness and health-related measures. Objective The purpose of this systematic review was to examine the validity and reliability of commercial wearables in measuring step count, heart rate, and energy expenditure. Methods We identified devices to be included in the review. Database searches were conducted in PubMed, Embase, and SPORTDiscus, and only articles published in the English language up to May 2019 were considered. Studies were excluded if they did not identify the device used and if they did not examine the validity or reliability of the device. Studies involving the general population and all special populations were included. We operationalized validity as criterion validity (as compared with other measures) and construct validity (degree to which the device is measuring what it claims). Reliability measures focused on intradevice and interdevice reliability. Results We included 158 publications examining nine different commercial wearable device brands. Fitbit was by far the most studied brand. In laboratory-based settings, Fitbit, Apple Watch, and Samsung appeared to measure steps accurately. Heart rate measurement was more variable, with Apple Watch and Garmin being the most accurate and Fitbit tending toward underestimation. For energy expenditure, no brand was accurate. We also examined validity between devices within a specific brand. Conclusions Commercial wearable devices are accurate for measuring steps and heart rate in laboratory-based settings, but this varies by the manufacturer and device type. Devices are constantly being upgraded and redesigned to new models, suggesting the need for more current reviews and research.

Polar Vantage and Oura physical activity and sleep trackers: A validation and comparison study

“…The strong correlation and low average error found for Oura RHR is in accordance with heart rate measurements from wrist-worn activity trackers [5, 32]. A recent validation study on Oura sleeping heart rate and heart rate variability also concluded high agreement between the Oura and an ECG [33].…”

“…Several systematic reviews on consumer-based activity tracker validity have been published the last few years with similar conclusions [27, 32, 34-39]. Fuller et al [32] published a large systematic review in 2020 assessing the validity of steps, energy expenditure, and heart rate estimates for devices from Apple, Fitbit, Garmin, Mio, Misfit, Polar, Samsung, Withings, and Xiaomi. From 148 included validation studies they concluded that, although there is variation, consumer-based activity trackers can accurately measure steps and heart rate in lab-settings.…”

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“…However, one previous study reported that the average wear time of smartphones among Chinese citizens was more than 13 hours during the day time, indicating that most walking activities should be captured by a smartphone [ 19 ]. Second, although our validation study demonstrated that daily step counts collected from iOS and Android devices both showed close agreement with actual step counts under controlled laboratory settings, previous studies found that iOS and Android devices have different accuracies in capturing the daily step count under free-living conditions [ 44 ]. This could have led to misclassification of daily step counts in this study.…”

Intelligence-Based Spine Care Model: A New Era of Research and Clinical Decision-Making

“…smart phones and watches) have been highly promoted as a means to improve health and modulate physical activity. Data collected from wearables is not entirely reliable, accuracy varies between manufacturers, 97 and the devices themselves have not demonstrated a meaningful impact on health care outcomes. 98 This is not to say consumer wearables are without the potential for clinical utility, as the Apple Watch has been shown to accurately detect paroxysmal atrial fibrillation.…”