{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,4,24]],"date-time":"2026-04-24T04:15:04Z","timestamp":1777004104506,"version":"3.51.4"},"reference-count":55,"publisher":"MDPI AG","issue":"14","license":[{"start":{"date-parts":[[2020,7,13]],"date-time":"2020-07-13T00:00:00Z","timestamp":1594598400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001871","name":"Funda\u00e7\u00e3o para a Ci\u00eancia e a Tecnologia","doi-asserted-by":"publisher","award":["PD\/BDE\/135569\/2018"],"award-info":[{"award-number":["PD\/BDE\/135569\/2018"]}],"id":[{"id":"10.13039\/501100001871","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Heart rate variability (HRV), using electrocardiography (ECG), has gained popularity as a biomarker of the stress response. Alternatives to HRV monitoring, like photoplethysmography (PPG), are being explored as cheaper and unobtrusive non-invasive technologies. We report a new wireless PPG sensor that was tested in detecting changes in HRV, elicited by a mentally stressful task, and to determine if its signal can be used as a surrogate of ECG for HRV analysis. Data were collected simultaneously from volunteers using a PPG and ECG sensor, during a resting and a mentally stressful task. HRV metrics were extracted from these signals and compared to determine the agreement between them and to determine if any changes occurred in the metrics due to the stressful task. For both tasks, a moderate\/good agreement was found in the mean interbeat intervals, SDNN, LF, and SD2, and a poor agreement for the pNN50, RMSSD|SD1, and HF metrics. The majority of the tested HRV metrics obtained from the PPG signal showed a significant decrease caused by the mental task. The disagreement found between specific HRV features imposes caution when comparing metrics from different technologies. Nevertheless, the tested sensor was successful at detecting changes in the HRV caused by a mental stressor.<\/jats:p>","DOI":"10.3390\/s20143905","type":"journal-article","created":{"date-parts":[[2020,7,14]],"date-time":"2020-07-14T09:30:49Z","timestamp":1594719049000},"page":"3905","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":34,"title":["Validation of a Wireless Bluetooth Photoplethysmography Sensor Used on the Earlobe for Monitoring Heart Rate Variability Features during a Stress-Inducing Mental Task in Healthy Individuals"],"prefix":"10.3390","volume":"20","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0103-0597","authenticated-orcid":false,"given":"Bruno","family":"Correia","sequence":"first","affiliation":[{"name":"Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal"},{"name":"ICVS\/3B\u2019s - PT Government Associate Laboratory, 4710-057 Braga\/Guimar\u00e3es, Portugal"},{"name":"iCognitus4ALL \u2013 IT Solutions, 4710-057 Braga, Portugal"}]},{"given":"Nuno","family":"Dias","sequence":"additional","affiliation":[{"name":"2Ai-Polytechnic Institute of C\u00e1vado and Ave, Campus do IPCA, 4750-810 Barcelos, Portugal"},{"name":"MindProber Labs, 4450-102 Porto, Portugal"}]},{"given":"Patr\u00edcio","family":"Costa","sequence":"additional","affiliation":[{"name":"Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal"},{"name":"ICVS\/3B\u2019s - PT Government Associate Laboratory, 4710-057 Braga\/Guimar\u00e3es, Portugal"}]},{"given":"Jos\u00e9 Miguel","family":"P\u00eago","sequence":"additional","affiliation":[{"name":"Life and Health Sciences Research Institute (ICVS), School of Medicine, University of Minho, 4710-057 Braga, Portugal"},{"name":"ICVS\/3B\u2019s - PT Government Associate Laboratory, 4710-057 Braga\/Guimar\u00e3es, Portugal"},{"name":"iCognitus4ALL \u2013 IT Solutions, 4710-057 Braga, Portugal"}]}],"member":"1968","published-online":{"date-parts":[[2020,7,13]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"669","DOI":"10.1007\/s00421-018-3808-0","article-title":"Validity of the Polar V800 monitor for measuring heart rate variability in mountain running route conditions","volume":"118","author":"Caminal","year":"2018","journal-title":"Eur. 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