Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation Study

Smart glasses are promising alternatives for the continuous, unobtrusive monitoring of heart rate (HR). This study validates HR estimates obtained with the “Essilor Connected Glasses” (SmartEW) during sedentary activities. Thirty participants wore the SmartEW, equipped with an IMU sensor for HR esti...

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Main Authors: Sarah Solbiati, Federica Mozzini, Jean Sahler, Paul Gil, Bruno Amir, Niccolò Antonello, Diana Trojaniello, Enrico Gianluca Caiani
Format: Article
Language:English
Published: MDPI AG 2025-07-01
Series:Sensors
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Online Access:https://www.mdpi.com/1424-8220/25/15/4531
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author Sarah Solbiati
Federica Mozzini
Jean Sahler
Paul Gil
Bruno Amir
Niccolò Antonello
Diana Trojaniello
Enrico Gianluca Caiani
author_facet Sarah Solbiati
Federica Mozzini
Jean Sahler
Paul Gil
Bruno Amir
Niccolò Antonello
Diana Trojaniello
Enrico Gianluca Caiani
author_sort Sarah Solbiati
collection DOAJ
description Smart glasses are promising alternatives for the continuous, unobtrusive monitoring of heart rate (HR). This study validates HR estimates obtained with the “Essilor Connected Glasses” (SmartEW) during sedentary activities. Thirty participants wore the SmartEW, equipped with an IMU sensor for HR estimation, a commercial smartwatch (Garmin Venu 3), and an ECG device (Movesense Flash). The protocol included six static tasks performed under controlled laboratory conditions. The SmartEW algorithm analyzed 22.5 s signal windows using spectral analysis to estimate HR and provide a quality index (QI). Statistical analyses assessed agreement with ECG and the impact of QI on HR accuracy. SmartEW showed high agreement with ECG, especially with QI threshold equal to 70, as a trade-off between accuracy, low error, and acceptable data coverage (80%). Correlation for QI ≥ 70 was high across all the experimental phases (r<sup>2</sup> up to 0.96), and the accuracy within ±5 bpm reached 95%. QI ≥ 70 also allowed biases to decrease (e.g., from −1.83 to −0.19 bpm while standing), with narrower limits of agreement, compared to ECG. SmartEW showed promising HR accuracy across sedentary activities, yielding high correlation and strong agreement with ECG and Garmin. SmartEW appears suitable for HR monitoring in static conditions, particularly when data quality is ensured.
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spelling doaj-art-5aa5a6d44cb34edfa0c25bc879cd59d62025-08-20T03:36:30ZengMDPI AGSensors1424-82202025-07-012515453110.3390/s25154531Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation StudySarah Solbiati0Federica Mozzini1Jean Sahler2Paul Gil3Bruno Amir4Niccolò Antonello5Diana Trojaniello6Enrico Gianluca Caiani7Department of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, MI, ItalyDepartment of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, MI, ItalyEssilorLuxottica, Smart Eyewear Lenses, Essilor International, 147 Rue de Paris, 94320 Créteil, FranceEssilorLuxottica, Smart Eyewear Lenses, Essilor International, 147 Rue de Paris, 94320 Créteil, FranceEssilorLuxottica, Smart Eyewear Lenses, Essilor International, 147 Rue de Paris, 94320 Créteil, FranceEssilorLuxottica, Smart Eyewear Lab, Piazzale Luigi Cadorna 3, 20123 Milan, MI, ItalyEssilorLuxottica, Smart Eyewear Lab, Piazzale Luigi Cadorna 3, 20123 Milan, MI, ItalyDepartment of Electronics, Information and Bioengineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, MI, ItalySmart glasses are promising alternatives for the continuous, unobtrusive monitoring of heart rate (HR). This study validates HR estimates obtained with the “Essilor Connected Glasses” (SmartEW) during sedentary activities. Thirty participants wore the SmartEW, equipped with an IMU sensor for HR estimation, a commercial smartwatch (Garmin Venu 3), and an ECG device (Movesense Flash). The protocol included six static tasks performed under controlled laboratory conditions. The SmartEW algorithm analyzed 22.5 s signal windows using spectral analysis to estimate HR and provide a quality index (QI). Statistical analyses assessed agreement with ECG and the impact of QI on HR accuracy. SmartEW showed high agreement with ECG, especially with QI threshold equal to 70, as a trade-off between accuracy, low error, and acceptable data coverage (80%). Correlation for QI ≥ 70 was high across all the experimental phases (r<sup>2</sup> up to 0.96), and the accuracy within ±5 bpm reached 95%. QI ≥ 70 also allowed biases to decrease (e.g., from −1.83 to −0.19 bpm while standing), with narrower limits of agreement, compared to ECG. SmartEW showed promising HR accuracy across sedentary activities, yielding high correlation and strong agreement with ECG and Garmin. SmartEW appears suitable for HR monitoring in static conditions, particularly when data quality is ensured.https://www.mdpi.com/1424-8220/25/15/4531smart eyewearwearablesphysiological monitoringheart rateinertial measurement unitquality index
spellingShingle Sarah Solbiati
Federica Mozzini
Jean Sahler
Paul Gil
Bruno Amir
Niccolò Antonello
Diana Trojaniello
Enrico Gianluca Caiani
Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation Study
Sensors
smart eyewear
wearables
physiological monitoring
heart rate
inertial measurement unit
quality index
title Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation Study
title_full Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation Study
title_fullStr Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation Study
title_full_unstemmed Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation Study
title_short Estimating Heart Rate from Inertial Sensors Embedded in Smart Eyewear: A Validation Study
title_sort estimating heart rate from inertial sensors embedded in smart eyewear a validation study
topic smart eyewear
wearables
physiological monitoring
heart rate
inertial measurement unit
quality index
url https://www.mdpi.com/1424-8220/25/15/4531
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