Assessment of Non-Invasive Measurements of Oxygen Saturation and Heart Rate with an Apple Smartwatch: Comparison with a Standard Pulse Oximeter
Open accessAbstract
The most commonly used method to assess peripheral oxygen saturation (SpO2) in clinical practice is pulse oximetry. The smartwatch Apple Watch 6 was developed with a new sensor and an app that allows taking on-demand readings of blood oxygen and background readings, day and night. The present study aimed to assess the feasibility and agreement of the Apple Watch 6 compared with a standard SpO2 monitoring system to assess normal and pathological oxygen saturation. We recruited study participants with lung disease or cardiovascular disease and healthy subjects. A total of 265 subjects were screened for enrolment in this study. We observed a strong positive correlation between the smartwatch and the standard commercial device in the evaluation of SpO2 measurements (r = 0.89, p < 0.0001) and HR measurements (r = 0.98, p < 0.0001). A very good concordance was found between SpO2 (bias, −0.2289; SD, 1.66; lower limit, −3.49; and upper limit, 3.04) and HR (bias, −0.1052; SD, 2.93; lower limit, −5.84; and upper limit, 5.63) measured by the smartwatch in comparison with the standard commercial device using Bland–Altman analysis. We observed similar agreements and concordance even in the different subgroups. In conclusion, our study demonstrates that the wearable device used in the present study could be used to assess SpO2 in patients with cardiovascular or lung diseases and in healthy subjects.
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The few existing studies do not investigate the effects of individual characteristics such as skin tone, compare across multiple devices, thoroughly examine performance in low ranges, or explore patterns of error and bias or missingness.
“The few studies that do exist do not investigate the effects of individual characteristics (e.g., skin tone), compare across multiple devices or thoroughly examine performance in low ranges, or explore patterns of error and bias (e.g., consistent over- or underestimation of measurements) or missingness [10–13].”
From Investigating the accuracy of blood oxygen saturation measurements in common consumer smartwatches (2023) · cites this paper as [11]
The Discussion (section 4) says all participants were white and few had oxygen saturation below 90%, supporting the skin-tone and low-range limitations. But the study compared an Apple Watch with a standard pulse oximeter (Methods, section 2), quantified measurement bias (Results, section 3), and reported cases where measurements could not be obtained (Results, section 3). Those parts of the citing sentence overstate what this study omitted. (LLM, conf=0.87)
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Cites
Large-Scale Assessment of a Smartwatch to Identify Atrial Fibrillation
Perez, M. V., Mahaffey, K. W., Hedlin, H., Rumsfeld, J. S., Garcia, A., Ferris, T., Balasubramanian, V., Russo, A. M., Rajmane, A., Cheung, L., et al. (2019) · New England Journal of Medicine · doi:10.1056/nejmoa1901183 · Cited by 1,917 · see citing works
Pipek, L. Z., Nascimento, R. F. V., Acencio, M. M. P., & Teixeira, L. R. (2021) · Scientific Reports · doi:10.1038/s41598-021-98453-3 · Cited by 87 · see citing works
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Research works printed but not linked: 11
- [1]Chan E.D. Chan M.M. Chan M.M. Pulse oximetry: Understanding its basic principles facilitates appreciation of its limitations Respir. Med. 2013 107 789 799 10.1016/j.rmed.2013.02.004 23490227 · DOI
- [4]Tison G. Sanchez J.M. Ballinger B. Singh A. Olgin J.E. Pletcher M.J. Vittinghoff E. Lee E.S. Fan S.M. Gladstone R.A. Passive Detection of Atrial Fibrillation Using a Commercially Available Smartwatch JAMA Cardiol. 2018 3 409 416 10.1001/jamacardio.2018.0136 29562087 PMC5875390 · DOI · Paper page
- [5]Bumgarner J.M. Lambert C.T. Hussein A.A. Cantillon D.J. Baranowski B. Wolski K. Lindsay B.D. Wazni O.M. Tarakji K.G. Smartwatch Algorithm for Automated Detection of Atrial Fibrillation J. Am. Coll. Cardiol. 2018 71 2381 2388 10.1016/j.jacc.2018.03.003 29535065 · DOI · Paper page
- [7]Spaccarotella C.A.M. Polimeni A. Migliarino S. Principe E. Curcio A. Mongiardo A. Sorrentino S. De Rosa S. Indolfi C. Multichannel Electrocardiograms Obtained by a Smartwatch for the Diagnosis of ST-Segment Changes JAMA Cardiol. 2020 5 1176 1180 10.1001/jamacardio.2020.3994 32865545 PMC7466842 · DOI
- [8]Spaccarotella C.A.M. Migliarino S. Mongiardo A. Sabatino J. Santarpia G. De Rosa S. Curcio A. Indolfi C. Measurement of the QT interval using the Apple Watch Sci. Rep. 2021 11 10817 10.1038/s41598-021-89199-z 34031432 PMC8144193 · DOI
- [9]Strik M. Caillol T. Ramirez F.D. Abu-Alrub S. Marchand H. Welte N. Ritter P. Haïssaguerre M. Ploux S. Bordachar P. Validating QT-Interval Measurement Using the Apple Watch ECG to Enable Remote Monitoring During the COVID-19 Pandemic Circulation 2020 142 416 418 10.1161/CIRCULATIONAHA.120.048253 32478565 PMC7382529 · DOI
- [10]Spaccarotella C. Santarpia G. Curcio A. Indolfi C. The smartwatch detects ECG abnormalities typical of Brugada syndrome J. Cardiovasc. Med. 2021 22 e24 e25 10.2459/JCM.0000000000001216 34054105 · DOI
- [12]Modi A.M. Kiourkas R.D. Li J. Scott J.B. Reliability of Smartphone Pulse Oximetry in Subjects at Risk for Hypoxemia Respir. Care 2021 66 384 390 10.4187/respcare.07670 33023999 · DOI
- [13]Liu J. Tang W. Chen G. Lu Y. Feng C. Tu X.M. Correlation and agreement: Overview and clarification of competing concepts and measures Shanghai Arch. Psychiatry 2016 28 115 120 27605869 PMC5004097
- [14]Bland J.M. Altman D.G. Measuring agreement in method comparison studies Stat. Methods Med. Res. 1999 8 135 160 10.1177/096228029900800204 10501650 · DOI · Paper page
- [17]Luks A.M. Swenson E.R. Pulse Oximetry for Monitoring Patients with COVID-19 at Home. Potential Pitfalls and Practical Guidance Ann. Am. Thorac. Soc. 2020 17 1040 1046 10.1513/AnnalsATS.202005-418FR 32521167 PMC7462317 · DOI
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Investigating the accuracy of blood oxygen saturation measurements in common consumer smartwatches
Jiang, Y., Spies, C., Magin, J., Bhosai, S. J., Snyder, L., & Dunn, J. (2023) · PLOS Digital Health · doi:10.1371/journal.pdig.0000296 · Cited by 36 · see citing works
Prefrontal tDCS modulates autonomic responses in COVID-19 inpatients
Pinto, T. P., Inácio, J. C., de Aguiar, E., Ferreira, A. S., Sudo, F. K., Tovar-Moll, F., & Rodrigues, E. C. (2023) · Brain Stimulation · doi:10.1016/j.brs.2023.03.001 · Cited by 11 · see citing works
- Authors
- Spaccarotella, C., Polimeni, A., Mancuso, C., Pelaia, G., Esposito, G., & Indolfi, C.
- Affiliations
- Federico II University Hospital (IT)
- Magna Graecia University (IT)
- Corresponding author
- Indolfi, Ciro
- Venue
- Journal of Clinical Medicine
- Publisher
- MDPI AG
- Published
- 2022-03-08
- Volume
- 11
- Issue
- 6
- Pages
- 1467
- ISSN
- 2077-0383 (ISSN-L)
- PMC
- PMC8951323
- OpenAlex
- W4220664803
- Cited by
- 65
- References
- 2
- Citations by year
- 2026: 8 · 2025: 11 · 2024: 15 · 2023: 23 · 2022: 8
- FWCI
- 4.14
- Type
- journal article
- Language
- en
- Open access
- gold
- doi.org
- Licence
- Locations
- Journal of Clinical Medicine (publishedVersion, cc-by)
- PubMed Central (publishedVersion, cc-by)
- PubMed (publishedVersion)
- Archive of Doctoral Theses and Digital Collections (University of Calabria) (submittedVersion)
- Topics
- Physical Sciences › Engineering › Biomedical Engineering › Non-Invasive Vital Sign Monitoring
- Health Sciences › Medicine › Surgery › Hemodynamic Monitoring and Therapy
- Health Sciences › Medicine › Complementary and alternative medicine › Cardiovascular and exercise physiology
- Keywords
- wearable devices, pulse oximetry, oxygen saturation, heart rate monitoring, non-invasive monitoring, device agreement, lung disease, cardiovascular disease, Bland-Altman analysis
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