{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T18:04:05Z","timestamp":1789495445415,"version":"build-2803163510"},"reference-count":39,"publisher":"Public Library of Science (PLoS)","issue":"9","license":[{"start":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T00:00:00Z","timestamp":1789430400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100027065","name":"Google Research","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100027065","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>\n                    Consumer wearables enable scalable physiological assessment and pre-symptomatic disease detection. However, validation of wearable data remains insufficient in scope and rigour, hindering integration into clinical and public health practice. Here, we evaluated the validity of VO\n                    <jats:sub>2<\/jats:sub>\n                    max, heart rate and energy expenditure from the Google Pixel Watch 3. Thirty-four participants completed a maximal exercise treadmill test using indirect calorimetry, while wearing a Polar H10 chest strap. Pixel Watch estimates of VO\n                    <jats:sub>2<\/jats:sub>\n                    max were generated in free-living conditions; heart rate and energy expenditure estimates were recorded during exercise testing. Bland-Altman analysis showed low bias but wide limits of agreement for VO\n                    <jats:sub>2<\/jats:sub>\n                    max estimates from the Pixel Watch 3 (bias \u22120.53 mL\/kg\/min; limits of agreement [LoA] \u221212.56 to 11.50; mean absolute percentage error [MAPE] 8.65%). Heart rate demonstrated strong agreement with the criterion overall, despite measurement variability (bias \u22122.39 bpm; LoA \u221224.42 to 19.65; MAPE 2.73%). The error for energy expenditure varied substantially between participants (bias \u22128.43 kcal; LoA \u221272.75 to 55.88; MAPE 15.02%). These results indicate that VO\n                    <jats:sub>2<\/jats:sub>\n                    max estimates lack sufficient individual-level validity for clinical use, although the bias suggests utility for population health monitoring. Heart rate showed acceptable error for exercise monitoring, whereas the large variation in error for energy expenditure limits its practical use. Our findings illustrate that wearable data require condition- and population-specific validation before incorporation into health care pathways.\n                  <\/jats:p>","DOI":"10.1371\/journal.pone.0356808","type":"journal-article","created":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T17:24:28Z","timestamp":1789493068000},"page":"e0356808","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":0,"title":["The accuracy of VO2 max, heart rate and energy expenditure measurements from Google Pixel Watch 3"],"prefix":"10.1371","volume":"21","author":[{"ORCID":"https:\/\/orcid.org\/0009-0009-5866-361X","authenticated-orcid":true,"given":"Rory","family":"Lambe","sequence":"first","affiliation":[{"name":"School of Public Health, Physiotherapy and Sports Science, University College Dublin","place":["Dublin, Ireland"]},{"name":"Rinn Artificial Intelligence, University College Dublin","place":["Dublin, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Moritz","family":"Schumann","sequence":"additional","affiliation":[{"name":"School of Medicine and Health, Experimental Exercise Science, Technical University of Munich","place":["Munich, Germany"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sherene","family":"Hamilton","sequence":"additional","affiliation":[{"name":"School of Public Health, Physiotherapy and Sports Science, University College Dublin","place":["Dublin, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lauren","family":"Donnelly","sequence":"additional","affiliation":[{"name":"School of Public Health, Physiotherapy and Sports Science, University College Dublin","place":["Dublin, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas","family":"White","sequence":"additional","affiliation":[{"name":"School of Public Health, Physiotherapy and Sports Science, University College Dublin","place":["Dublin, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Se\u00e1n","family":"O\u2019Reilly","sequence":"additional","affiliation":[{"name":"School of Public Health, Physiotherapy and Sports Science, University College Dublin","place":["Dublin, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Saoirse","family":"Lally","sequence":"additional","affiliation":[{"name":"School of Public Health, Physiotherapy and Sports Science, University College Dublin","place":["Dublin, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cailbhe","family":"Doherty","sequence":"additional","affiliation":[{"name":"School of Public Health, Physiotherapy and Sports Science, University College Dublin","place":["Dublin, Ireland"]},{"name":"Rinn Artificial Intelligence, University College Dublin","place":["Dublin, Ireland"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2026,9,15]]},"reference":[{"issue":"4","key":"pone.0356808.ref001","article-title":"Remote digital health technologies for improving the care of people with respiratory disorders","volume":"6","author":"J Dunn","year":"2024","journal-title":"Lancet Digit Health"},{"issue":"18","key":"pone.0356808.ref002","doi-asserted-by":"crossref","first-page":"1975","DOI":"10.1093\/eurjpc\/zwad229","article-title":"The association between daily step count and all-cause and cardiovascular mortality: a meta-analysis","volume":"30","author":"M Banach","year":"2023","journal-title":"Eur J Prev Cardiol"},{"issue":"3","key":"pone.0356808.ref003","doi-asserted-by":"crossref","DOI":"10.1503\/cmaj.150535","article-title":"Resting heart rate and all-cause and cardiovascular mortality in the general population: a meta-analysis","volume":"188","author":"D Zhang","year":"2016","journal-title":"CMAJ"},{"issue":"1","key":"pone.0356808.ref004","doi-asserted-by":"crossref","first-page":"242","DOI":"10.1038\/s41746-024-01187-5","article-title":"Understanding activity and physiology at scale: The Apple Heart & Movement Study","volume":"7","author":"J Truslow","year":"2024","journal-title":"NPJ Digit Med"},{"issue":"8109","key":"pone.0356808.ref005","doi-asserted-by":"crossref","first-page":"451","DOI":"10.1038\/s41586-026-10179-2","article-title":"Insulin resistance prediction from wearables and routine blood biomarkers","volume":"652","author":"AA Metwally","year":"2026","journal-title":"Nature"},{"issue":"1","key":"pone.0356808.ref006","doi-asserted-by":"crossref","first-page":"89","DOI":"10.1038\/s41746-021-00465-w","article-title":"Engineering digital biomarkers of interstitial glucose from noninvasive smartwatches","volume":"4","author":"B Bent","year":"2021","journal-title":"NPJ Digit Med"},{"issue":"7","key":"pone.0356808.ref007","doi-asserted-by":"crossref","first-page":"100886","DOI":"10.1016\/j.landig.2025.100886","article-title":"Development of machine learning prediction models for systemic inflammatory response following controlled exposure to a live attenuated influenza vaccine in healthy adults using multimodal wearable biosensors in Canada: a single-centre, prospective controlled trial","volume":"7","author":"A Hadid","year":"2025","journal-title":"Lancet Digit Health"},{"issue":"11","key":"pone.0356808.ref008","doi-asserted-by":"crossref","first-page":"2907","DOI":"10.1007\/s40279-024-02077-2","article-title":"Keeping pace with wearables: a living umbrella review of systematic reviews evaluating the accuracy of consumer wearable technologies in health measurement","volume":"54","author":"C Doherty","year":"2024","journal-title":"Sports Med"},{"issue":"24","key":"pone.0356808.ref009","doi-asserted-by":"crossref","DOI":"10.1161\/CIR.0000000000000461","article-title":"Importance of assessing cardiorespiratory fitness in clinical practice: a case for fitness as a clinical vital sign: a scientific statement from the American Heart Association","volume":"134","author":"R Ross","year":"2016","journal-title":"Circulation"},{"issue":"2","key":"pone.0356808.ref010","doi-asserted-by":"crossref","first-page":"171","DOI":"10.1001\/jama.296.2.171","article-title":"Daily activity energy expenditure and mortality among older adults","volume":"296","author":"TM Manini","year":"2006","journal-title":"JAMA"},{"issue":"2","key":"pone.0356808.ref011","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1001\/jamainternmed.2020.6331","article-title":"Association of physical activity intensity with mortality: A National Cohort Study of 403 681 US Adults","volume":"181","author":"Y Wang","year":"2021","journal-title":"JAMA Intern Med"},{"issue":"1","key":"pone.0356808.ref012","doi-asserted-by":"crossref","first-page":"63","DOI":"10.1038\/s41746-025-02238-1","article-title":"The accuracy of Apple Watch measurements: a living systematic review and meta-analysis","volume":"9","author":"R Lambe","year":"2026","journal-title":"NPJ Digit Med"},{"issue":"5","key":"pone.0356808.ref013","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0323741","article-title":"Investigating the accuracy of Apple Watch VO2 max measurements: A validation study","volume":"20","author":"R Lambe","year":"2025","journal-title":"PLoS One"},{"key":"pone.0356808.ref014","first-page":"100357","article-title":"Accuracy of VO2 max Estimates from Apple Watch Series 10","volume":"2026","author":"R Lambe","year":"2026","journal-title":"Mayo Clinic Proceedings: Digital Health"},{"issue":"8","key":"pone.0356808.ref015","doi-asserted-by":"crossref","first-page":"1817","DOI":"10.1007\/s40279-022-01665-4","article-title":"Recommendations for determining the validity of consumer wearables and smartphones for the estimation of energy expenditure: expert statement and checklist of the INTERLIVE Network","volume":"52","author":"R Argent","year":"2022","journal-title":"Sports Med"},{"key":"pone.0356808.ref016","doi-asserted-by":"crossref","first-page":"18","DOI":"10.1038\/s41746-020-0226-6","article-title":"Investigating sources of inaccuracy in wearable optical heart rate sensors","volume":"3","author":"B Bent","year":"2020","journal-title":"NPJ Digit Med"},{"issue":"7","key":"pone.0356808.ref017","doi-asserted-by":"crossref","first-page":"1577","DOI":"10.1007\/s40279-021-01639-y","article-title":"Validity of estimating the maximal oxygen consumption by consumer wearables: a systematic review with meta-analysis and expert statement of the INTERLIVE Network","volume":"52","author":"P Molina-Garcia","year":"2022","journal-title":"Sports Med"},{"key":"pone.0356808.ref018","doi-asserted-by":"crossref","first-page":"55","DOI":"10.1038\/s41746-020-0260-4","article-title":"Verification, analytical validation, and clinical validation (V3): the foundation of determining fit-for-purpose for Biometric Monitoring Technologies (BioMeTs)","volume":"3","author":"JC Goldsack","year":"2020","journal-title":"NPJ Digit Med"},{"key":"pone.0356808.ref019","volume-title":"ACSM\u2019s Guidelines for Exercise Testing and Prescription","author":"C Ozemek","year":"2025"},{"issue":"1","key":"pone.0356808.ref020","doi-asserted-by":"crossref","first-page":"39","DOI":"10.1016\/S0002-8703(76)80401-2","article-title":"A comparative analysis of four protocols for maximal treadmill stress testing","volume":"92","author":"ML Pollock","year":"1976","journal-title":"Am Heart J"},{"issue":"6","key":"pone.0356808.ref021","doi-asserted-by":"crossref","first-page":"869","DOI":"10.1001\/archderm.1988.01670060015008","article-title":"The validity and practicality of sun-reactive skin types I through VI","volume":"124","author":"TB Fitzpatrick","year":"1988","journal-title":"Arch Dermatol"},{"key":"pone.0356808.ref022","doi-asserted-by":"crossref","DOI":"10.1016\/j.mayocp.2021.08.020","volume-title":"Updated reference standards for cardiorespiratory fitness measured with cardiopulmonary exercise testing: data from the Fitness Registry and the Importance of Exercise National Database (FRIEND)","author":"LA Kaminsky","year":"2022"},{"issue":"17","key":"pone.0356808.ref023","doi-asserted-by":"crossref","first-page":"6536","DOI":"10.3390\/s22176536","article-title":"Validity of the polar H10 sensor for heart rate variability analysis during resting state and incremental exercise in recreational men and women","volume":"22","author":"M Schaffarczyk","year":"2022","journal-title":"Sensors (Basel)"},{"issue":"14","key":"pone.0356808.ref024","doi-asserted-by":"crossref","first-page":"767","DOI":"10.1136\/bjsports-2020-103148","article-title":"Recommendations for determining the validity of consumer wearable heart rate devices: expert statement and checklist of the INTERLIVE Network","volume":"55","author":"JM M\u00fchlen","year":"2021","journal-title":"Br J Sports Med"},{"key":"pone.0356808.ref025","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1113\/jphysiol.1949.sp004363","article-title":"New methods for calculating metabolic rate with special reference to protein metabolism","volume":"109","author":"JBDB Weir","year":"1949","journal-title":"J Physiol"},{"key":"pone.0356808.ref026","doi-asserted-by":"crossref","DOI":"10.2196\/59459","article-title":"Assessing the Accuracy of Smartwatch-Based Estimation of Maximum Oxygen Uptake Using the Apple Watch Series 7: Validation Study","volume":"9","author":"P Caserman","year":"2024","journal-title":"JMIR Biomed Eng"},{"issue":"8476","key":"pone.0356808.ref027","doi-asserted-by":"crossref","first-page":"307","DOI":"10.1016\/S0140-6736(86)90837-8","article-title":"Statistical methods for assessing agreement between two methods of clinical measurement","volume":"1","author":"JM Bland","year":"1986","journal-title":"Lancet"},{"issue":"2","key":"pone.0356808.ref028","doi-asserted-by":"crossref","first-page":"135","DOI":"10.1177\/096228029900800204","article-title":"Measuring agreement in method comparison studies","volume":"8","author":"JM Bland","year":"1999","journal-title":"Stat Methods Med Res"},{"issue":"4","key":"pone.0356808.ref029","doi-asserted-by":"crossref","first-page":"571","DOI":"10.1080\/10543400701329422","article-title":"Agreement between methods of measurement with multiple observations per individual","volume":"17","author":"JM Bland","year":"2007","journal-title":"J Biopharm Stat"},{"issue":"6","key":"pone.0356808.ref030","doi-asserted-by":"crossref","first-page":"1054","DOI":"10.1016\/j.mayocp.2022.02.029","article-title":"Objectively assessed cardiorespiratory fitness and all-cause mortality risk: an updated meta-analysis of 37 cohort studies involving 2,258,029 participants","volume":"97","author":"JA Laukkanen","year":"2022","journal-title":"Mayo Clin Proc"},{"issue":"5","key":"pone.0356808.ref031","doi-asserted-by":"crossref","first-page":"737","DOI":"10.1007\/s40279-015-0445-1","article-title":"Validity of submaximal step tests to estimate maximal oxygen uptake in healthy adults","volume":"46","author":"H Bennett","year":"2016","journal-title":"Sports Med"},{"issue":"19","key":"pone.0356808.ref032","doi-asserted-by":"crossref","first-page":"6220","DOI":"10.3390\/s24196220","article-title":"The validity of Apple Watch Series 9 and ultra 2 for serial measurements of heart rate variability and resting heart rate","volume":"24","author":"B O\u2019Grady","year":"2024","journal-title":"Sensors (Basel)"},{"issue":"4","key":"pone.0356808.ref033","doi-asserted-by":"crossref","DOI":"10.2196\/35626","article-title":"Accuracy and precision of energy expenditure, heart rate, and steps measured by combined-sensing fitbits against reference measures: systematic review and meta-analysis","volume":"10","author":"G Chevance","year":"2022","journal-title":"JMIR Mhealth Uhealth"},{"issue":"9","key":"pone.0356808.ref034","doi-asserted-by":"crossref","DOI":"10.2196\/18694","article-title":"Reliability and validity of commercially available wearable devices for measuring steps, energy expenditure, and heart rate: systematic review","volume":"8","author":"D Fuller","year":"2020","journal-title":"JMIR Mhealth Uhealth"},{"issue":"6","key":"pone.0356808.ref035","doi-asserted-by":"crossref","first-page":"332","DOI":"10.1136\/bjsports-2018-099643","article-title":"How well do activity monitors estimate energy expenditure? A systematic review and meta-analysis of the validity of current technologies","volume":"54","author":"R O\u2019Driscoll","year":"2020","journal-title":"Br J Sports Med"},{"key":"pone.0356808.ref036","doi-asserted-by":"crossref","DOI":"10.1097\/00005768-200106001-00013","article-title":"Individual differences in response to regular physical activity","volume":"33","author":"C Bouchard","year":"2001","journal-title":"Med Sci Sports Exerc"},{"key":"pone.0356808.ref037","unstructured":"Using Apple Watch to Estimate Cardio Fitness with VO2 max. Apple Healthcare: Apple; 2021."},{"key":"pone.0356808.ref038","unstructured":"Apple. Using Apple Watch to measure heart rate, calorimetry, and activity. Apple Health; 2024."},{"issue":"2","key":"pone.0356808.ref039","first-page":"128","article-title":"Readiness, recovery, and strain: an evaluation of composite health scores in consumer wearables","volume":"2","author":"C Doherty","year":"2025","journal-title":"Transl Exerc Biomed"}],"container-title":["PLOS One"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0356808","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2026,9,15]],"date-time":"2026-09-15T17:24:35Z","timestamp":1789493075000},"score":1,"resource":{"primary":{"URL":"https:\/\/dx.plos.org\/10.1371\/journal.pone.0356808"}},"subtitle":[],"editor":[{"given":"Agnese","family":"Sbrollini","sequence":"first","affiliation":[{"name":"Polytechnic University of Marche: Universita Politecnica delle Marche","place":["ITALY"]}],"role":[{"vocabulary":"crossref","role":"editor"}]}],"short-title":[],"issued":{"date-parts":[[2026,9,15]]},"references-count":39,"journal-issue":{"issue":"9","published-online":{"date-parts":[[2026,9,15]]}},"URL":"https:\/\/doi.org\/10.1371\/journal.pone.0356808","relation":{},"ISSN":["1932-6203"],"issn-type":[{"value":"1932-6203","type":"electronic"}],"subject":[],"published":{"date-parts":[[2026,9,15]]}}}