Cited by 625Non-Invasive Vital Sign MonitoringContext-Aware Activity Recognition SystemsPhysical Activity and Health

Accuracy in Wrist-Worn, Sensor-Based Measurements of Heart Rate and Energy Expenditure in a Diverse Cohort

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Shcherbina, Anna, Mattsson, C., Waggott, Daryl, Salisbury, Heidi, Christle, Jeffrey, Hastie, Trevor, Wheeler, Matthew, Ashley, Euan·2017·Journal of Personalized Medicine

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Abstract

The ability to measure physical activity through wrist-worn devices provides an opportunity for cardiovascular medicine. However, the accuracy of commercial devices is largely unknown. The aim of this work is to assess the accuracy of seven commercially available wrist-worn devices in estimating heart rate (HR) and energy expenditure (EE) and to propose a wearable sensor evaluation framework. We evaluated the Apple Watch, Basis Peak, Fitbit Surge, Microsoft Band, Mio Alpha 2, PulseOn, and Samsung Gear S2. Participants wore devices while being simultaneously assessed with continuous telemetry and indirect calorimetry while sitting, walking, running, and cycling. Sixty volunteers (29 male, 31 female, age 38 ± 11 years) of diverse age, height, weight, skin tone, and fitness level were selected. Error in HR and EE was computed for each subject/device/activity combination. Devices reported the lowest error for cycling and the highest for walking. Device error was higher for males, greater body mass index, darker skin tone, and walking. Six of the devices achieved a median error for HR below 5% during cycling. No device achieved an error in EE below 20 percent. The Apple Watch achieved the lowest overall error in both HR and EE, while the Samsung Gear S2 reported the highest. In conclusion, most wrist-worn devices adequately measure HR in laboratory-based activities, but poorly estimate EE, suggesting caution in the use of EE measurements as part of health improvement programs. We propose reference standards for the validation of consumer health devices (http://precision.stanford.edu/).

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Crossref · 10.3390/jpm7020003

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  • Wearable devices have higher error during activity than at rest.

    “Our analyses reinforces the growing body of research demonstrating that wearable devices have higher error during activity than at rest.8,11,35,38,39”

    From Investigating sources of inaccuracy in wearable optical heart rate sensors (2020) · cites this paper as [11]

    The Results (§3.2; page unavailable) report the opposite for energy expenditure: error was highest while sitting and lower during walking and running. The paper also finds that heart-rate error varies by activity rather than establishing that it is generally higher during activity than at rest (§3.1 and §3.4). (LLM, conf=0.87)

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    Experimental — accuracy not yet measured
  • Apple Watch devices showed less than 5 bpm variation across skin tones.

    “In contrast, Apple Watch devices were more consistent, with <5 bpm variation across skin tones, findings supported by Sañudo et al. (2019) and Shcherbina et al. (2017) [7,10].”

    From Photoplethysmography in Diverse Skin Tones: Evaluating Bias in Smartwatch Health Monitoring (2025) · cites this paper as [10]

    The Results (§3.1) report that the Apple Watch had the lowest overall heart-rate error among the tested devices, and the Discussion (§4) notes that participants varied in skin tone. But the paper reports error as a percentage, not a less-than-5-bpm variation across skin tones; it also notes that darker skin tone correlated with increased error across multiple devices. (LLM, conf=0.87)

    Experimental — accuracy not yet measured
  • A 5% level of accuracy was adopted as the widely accepted acceptable limit.

    “We adopted the widely accepted level of accuracy of 5% to be within the acceptable limits [16].”

    From Accuracy of Wrist-Worn Activity Monitors During Common Daily Physical Activities and Types of Structured Exercise: Evaluation Study (2018) · cites this paper as [16]

    The Methods (§2.5, Error) set 5% error as within acceptable limits. But the paper calls statistical significance—not 5% measurement accuracy—a widely accepted standard, and the Discussion (§4) describes its clinically acceptable error threshold as a proposed standard. It therefore supports adopting the 5% limit, but not calling that accuracy limit widely accepted. (LLM, conf=0.87)

    Experimental — accuracy not yet measured
  • In recent studies involving predominantly steady-state aerobic activities, wrist-worn activity monitors have been shown to have reasonable accuracy in heart rate estimation (approximately 5% error) but a poor estimate of energy expenditure, where the error was found to be closer to approximately 30% with a negative bias.

    “In recent studies involving predominantly steady-state aerobic activities, wrist-worn activity monitors have been shown to have reasonable accuracy in HR estimation (approximately 5% error) but a poor estimate of EE, where the error was found to be closer to approximately 30% with a negative bias [16,17].”

    From Accuracy of Wrist-Worn Activity Monitors During Common Daily Physical Activities and Types of Structured Exercise: Evaluation Study (2018) · cites this paper as [16]

    Split into 2 atoms — 1 confirmed, 1 partially supported, 0 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

    Experimental — accuracy not yet measured
  • Heart rate measurements from wearable devices are often less accurate during physical activity or cyclic wrist motions.

    “Several studies have demonstrated that HR measurements from wearable devices are often less accurate during physical activity or cyclic wrist motions.”

    From Investigating sources of inaccuracy in wearable optical heart rate sensors (2020) · cites this paper as [11]

    The Discussion reports higher heart-rate error at higher intensity within each activity, and Results §3.1 reports more error during walking than cycling. But the paper does not assess cyclic wrist motions, and its Conclusions say heart-rate measurements were within an acceptable error range in most activity settings; it does not support a general claim that physical activity makes them less accurate. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

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Authors
Shcherbina, A., Mattsson, C., Waggott, D., Salisbury, H., Christle, J., Hastie, T., Wheeler, M., & Ashley, E.
Affiliations
  • Stanford Medicine (US)
  • Swedish School of Sport and Health Sciences (SE)
  • Stanford University (US)
Corresponding author
Ashley, Euan
Venue
Journal of Personalized Medicine
Publisher
MDPI AG
Published
2017-05-24
Volume
7
Issue
2
Pages
3
ISSN
2075-4426 (ISSN-L)
OpenAlex
W2618581983
Cited by
625
References
20
Citations by year
2026: 64 · 2025: 63 · 2024: 52 · 2023: 71 · 2022: 74 · 2021: 79 · 2020: 72 · 2019: 90 · 2018: 50 · 2017: 9 · 2014: 1
FWCI
27.19
Type
journal article
Language
en
Open access
Locations
  • Journal of Personalized Medicine (publishedVersion, cc-by)
  • bioRxiv (Cold Spring Harbor Laboratory) (acceptedVersion, cc-by-nd)
  • Europe PMC (PubMed Central) (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • PubMed (publishedVersion)
  • KTH Publication Database DiVA (KTH Royal Institute of Technology) (submittedVersion, other-oa)
Funders
Food And Drug Administration (125614)
Topics
  • Physical Sciences › Engineering › Biomedical Engineering › Non-Invasive Vital Sign Monitoring
  • Physical Sciences › Computer Science › Computer Vision and Pattern Recognition › Context-Aware Activity Recognition Systems
  • Health Sciences › Medicine › Physiology › Physical Activity and Health
Keywords
wrist-worn devices, wearable sensors, heart rate measurement, energy expenditure estimation, device accuracy, consumer health devices, Apple Watch, Fitbit, indirect calorimetry, physical activity monitoring, skin tone, body mass index, sex differences, walking and cycling

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