{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,2]],"date-time":"2026-04-02T13:41:47Z","timestamp":1775137307899,"version":"3.50.1"},"reference-count":39,"publisher":"MDPI AG","issue":"8","license":[{"start":{"date-parts":[[2018,8,10]],"date-time":"2018-08-10T00:00:00Z","timestamp":1533859200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100005053","name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red en Bioingenier\u00eda, Biomateriales y Nanomedicina","doi-asserted-by":"publisher","award":["--"],"award-info":[{"award-number":["--"]}],"id":[{"id":"10.13039\/501100005053","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100010198","name":"Ministerio de Econom\u00eda, Industria y Competitividad, Gobierno de Espa\u00f1a","doi-asserted-by":"publisher","award":["TIN2016-76770-R"],"award-info":[{"award-number":["TIN2016-76770-R"]}],"id":[{"id":"10.13039\/501100010198","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Arag\u00f3n Government","award":["Grupo de Referencia BSICoS (T39_17R)"],"award-info":[{"award-number":["Grupo de Referencia BSICoS (T39_17R)"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Heart rate variability (HRV) analysis is a noninvasive tool widely used to assess autonomic nervous system state. The market for wearable devices that measure the heart rate has grown exponentially, as well as their potential use for healthcare and wellbeing applications. Still, there is a lack of validation of these devices. In particular, this work aims to validate the Apple Watch in terms of HRV derived from the RR interval series provided by the device, both in temporal (HRM (mean heart rate), SDNN, RMSSD and pNN50) and frequency (low and high frequency powers, LF and HF) domain. For this purpose, a database of 20 healthy volunteers subjected to relax and a mild cognitive stress was used. First, RR interval series provided by Apple Watch were validated using as reference the RR interval series provided by a Polar H7 using Bland-Altman plots and reliability and agreement coefficients. Then, HRV parameters derived from both RR interval series were compared and their ability to identify autonomic nervous system (ANS) response to mild cognitive stress was studied. Apple Watch measurements presented very good reliability and agreement (&gt;0.9). RR interval series provided by Apple Watch contain gaps due to missing RR interval values (on average, 5 gaps per recording, lasting 6.5 s per gap). Temporal HRV indices were not significantly affected by the gaps. However, they produced a significant decrease in the LF and HF power. Despite these differences, HRV indices derived from the Apple Watch RR interval series were able to reflect changes induced by a mild mental stress, showing a significant decrease of HF power as well as RMSSD in stress with respect to relax, suggesting the potential use of HRV measurements derived from Apple Watch for stress monitoring.<\/jats:p>","DOI":"10.3390\/s18082619","type":"journal-article","created":{"date-parts":[[2018,8,10]],"date-time":"2018-08-10T10:52:01Z","timestamp":1533898321000},"page":"2619","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":204,"title":["Validation of the Apple Watch for Heart Rate Variability Measurements during Relax and Mental Stress in Healthy Subjects"],"prefix":"10.3390","volume":"18","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-1462-4880","authenticated-orcid":false,"given":"David","family":"Hernando","sequence":"first","affiliation":[{"name":"Biomedical Signal Interpretation &amp; Computational Simulation (BSICoS) Group, Arag\u00f3n Institute of Engineering Research (I3A), IIS Arag\u00f3n, University of Zaragoza, 50018 Zaragoza, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red en Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain"}]},{"given":"Surya","family":"Roca","sequence":"additional","affiliation":[{"name":"Communications Networks and Information Technologies (CeNIT) Group, Arag\u00f3n Institute of Engineering Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8518-6884","authenticated-orcid":false,"given":"Jorge","family":"Sancho","sequence":"additional","affiliation":[{"name":"Communications Networks and Information Technologies (CeNIT) Group, Arag\u00f3n Institute of Engineering Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-5254-1402","authenticated-orcid":false,"given":"\u00c1lvaro","family":"Alesanco","sequence":"additional","affiliation":[{"name":"Communications Networks and Information Technologies (CeNIT) Group, Arag\u00f3n Institute of Engineering Research (I3A), University of Zaragoza, 50018 Zaragoza, Spain"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-1272-0550","authenticated-orcid":false,"given":"Raquel","family":"Bail\u00f3n","sequence":"additional","affiliation":[{"name":"Biomedical Signal Interpretation &amp; Computational Simulation (BSICoS) Group, Arag\u00f3n Institute of Engineering Research (I3A), IIS Arag\u00f3n, University of Zaragoza, 50018 Zaragoza, Spain"},{"name":"Centro de Investigaci\u00f3n Biom\u00e9dica en Red en Bioingenier\u00eda, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain"}]}],"member":"1968","published-online":{"date-parts":[[2018,8,10]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1043","DOI":"10.1161\/01.CIR.93.5.1043","article-title":"Heart rate variability: Standards of measurement, physiological interpretation, and clinical use","volume":"93","author":"Camm","year":"1996","journal-title":"Circulation"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"747","DOI":"10.1016\/j.neubiorev.2011.11.009","article-title":"A meta-analysis of heart rate variability and neuroimaging studies: Implications for heart rate variability as a marker of stress and health","volume":"36","author":"Thayer","year":"2012","journal-title":"Neurosci. 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