{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,22]],"date-time":"2026-06-22T15:07:55Z","timestamp":1782140875535,"version":"3.54.5"},"reference-count":32,"publisher":"MDPI AG","issue":"3","license":[{"start":{"date-parts":[[2020,2,6]],"date-time":"2020-02-06T00:00:00Z","timestamp":1580947200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["U01 EB0220003-01"],"award-info":[{"award-number":["U01 EB0220003-01"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["1P30ES023513-01A1"],"award-info":[{"award-number":["1P30ES023513-01A1"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100000002","name":"National Institutes of Health","doi-asserted-by":"publisher","award":["UG3-OD023365"],"award-info":[{"award-number":["UG3-OD023365"]}],"id":[{"id":"10.13039\/100000002","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/100006108","name":"National Center for Advancing Translational Sciences","doi-asserted-by":"publisher","award":["UL1 TR000002"],"award-info":[{"award-number":["UL1 TR000002"]}],"id":[{"id":"10.13039\/100006108","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Sensors"],"abstract":"<jats:p>Mobile health monitoring via non-invasive wearable sensors is poised to advance telehealth for older adults and other vulnerable populations. Extreme heat and other environmental conditions raise serious health challenges that warrant monitoring of real-time physiological data as people go about their normal activities. Mobile systems could be beneficial for many communities, including elite athletes, military special forces, and at-home geriatric monitoring. While some commercial monitors exist, they are bulky, require reconfiguration, and do not fit seamlessly as a simple wearable device. We designed, prototyped and tested an integrated sensor platform that records heart rate, oxygen saturation, physical activity levels, skin temperature, and galvanic skin response. The device uses a small microcontroller to integrate the measurements and store data directly on the device for up to 48+ h. continuously. The device was compared to clinical standards for calibration and performance benchmarking. We found that our system compared favorably with clinical measures, such as fingertip pulse oximetry and infrared thermometry, with high accuracy and correlation. Our novel platform would facilitate an individualized approach to care, particularly those whose access to healthcare facilities is limited. The platform also can be used as a research tool to study physiological responses to a variety of environmental conditions, such as extreme heat, and can be customized to incorporate new sensors to explore other lines of inquiry.<\/jats:p>","DOI":"10.3390\/s20030855","type":"journal-article","created":{"date-parts":[[2020,2,7]],"date-time":"2020-02-07T03:13:27Z","timestamp":1581045207000},"page":"855","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":63,"title":["Wearable Sensor System to Monitor Physical Activity and the Physiological Effects of Heat Exposure"],"prefix":"10.3390","volume":"20","author":[{"given":"Sean","family":"Pham","sequence":"first","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Danny","family":"Yeap","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gisela","family":"Escalera","sequence":"additional","affiliation":[{"name":"Center for Healthcare Policy and Research, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rupa","family":"Basu","sequence":"additional","affiliation":[{"name":"California Environmental Protection Agency, California Office of Environmental Health Hazard Assessment, 1515 Clay Street, Oakland, CA 94612, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7429-4177","authenticated-orcid":false,"given":"Xiangmei","family":"Wu","sequence":"additional","affiliation":[{"name":"California Environmental Protection Agency, California Office of Environmental Health Hazard Assessment, 1515 Clay Street, Oakland, CA 94612, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8839-4400","authenticated-orcid":false,"given":"Nicholas J.","family":"Kenyon","sequence":"additional","affiliation":[{"name":"Department of Internal Medicine, 4150 V Street, Suite 3400, University of California, Davis, Sacramento, CA 95817, USA"},{"name":"Center for Comparative Respiratory Biology and Medicine, University of California, Davis, CA 95616, USA"},{"name":"VA Northern California Health Care System, 10535 Hospital Way, Mather, CA 95655, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Irva","family":"Hertz-Picciotto","sequence":"additional","affiliation":[{"name":"Division of Environmental and Occupational Health, Department of Public Health, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michelle J.","family":"Ko","sequence":"additional","affiliation":[{"name":"Center for Regional Change, Department of Public Health, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Cristina E.","family":"Davis","sequence":"additional","affiliation":[{"name":"Department of Mechanical and Aerospace Engineering, University of California, Davis, CA 95616, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2020,2,6]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"813","DOI":"10.1097\/EDE.0b013e31826b7f97","article-title":"The effect of high ambient temperature on emergency room visits","volume":"23","author":"Basu","year":"2012","journal-title":"Epidemiology"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"429","DOI":"10.1016\/j.amepre.2008.08.021","article-title":"Climate Change and Extreme Heat Events","volume":"35","author":"Luber","year":"2008","journal-title":"Am. J. Prev. Med."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"9","DOI":"10.2165\/00007256-200434010-00002","article-title":"Heat Illness in Athletes","volume":"34","author":"Coris","year":"2004","journal-title":"Sports Med."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"156","DOI":"10.1177\/1059840517706104","article-title":"Exertional Heat Illness Among Secondary School Athletes","volume":"34","author":"Rodgers","year":"2017","journal-title":"J. Sch. Nurs."},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"1384","DOI":"10.1177\/0363546507305013","article-title":"Heat-Related Illness in Athletes","volume":"35","author":"Howe","year":"2007","journal-title":"Am. J. Sports Med."},{"key":"ref_6","first-page":"353","article-title":"The Effects of Acute Heat Exposure on Muscular Strength, Muscular Endurance, and Muscular Power in the Euhydrated Athlete","volume":"16","author":"Hedley","year":"2002","journal-title":"J. Strength Cond. Res."},{"key":"ref_7","doi-asserted-by":"crossref","first-page":"1827","DOI":"10.1007\/s00421-011-2153-3","article-title":"Effectiveness of short-term heat acclimation for highly trained athletes","volume":"112","author":"Garrett","year":"2011","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"623","DOI":"10.1093\/milmed\/162.9.623","article-title":"The Effects of Prolonged Passive Heat Exposure and Basic Military Training on Thermoregulatory and Cardiovascular Responses in Recruits from a Tropical Country","volume":"162","author":"Lim","year":"1997","journal-title":"Mil. Med."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"84","DOI":"10.1249\/01.MSS.0000150018.90213.AA","article-title":"The Effects of Continuous Hot Weather Training on Risk of Exertional Heat Illness","volume":"37","author":"Wallace","year":"2005","journal-title":"Med. Sci. Sports Exerc."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"298","DOI":"10.1093\/milmed\/168.4.298","article-title":"Exertional Heat Illness in Air Force Basic Military Trainees","volume":"168","author":"Smalley","year":"2003","journal-title":"Mil. Med."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"1779","DOI":"10.1007\/s00484-013-0752-x","article-title":"The epidemiology of occupational heat exposure in the United States: A review of the literature and assessment of research needs in a changing climate","volume":"58","author":"Gubernot","year":"2013","journal-title":"Int. J. Biometeorol."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"14","DOI":"10.1186\/2046-7648-3-14","article-title":"Excessive occupational heat exposure: A significant ergonomic challenge and health risk for current and future workers","volume":"3","author":"Lucas","year":"2014","journal-title":"Extrem. Physiol. Med."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"341","DOI":"10.1016\/j.autcon.2017.06.012","article-title":"Wearable sensors for monitoring on-duty and off-duty worker physiological status and activities in construction","volume":"83","author":"Lee","year":"2017","journal-title":"Autom. Constr."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"203","DOI":"10.1002\/ajim.22381","article-title":"Characterizing occupational heat-related mortality in the United States, 2000\u20132010: An analysis using the census of fatal occupational injuries database","volume":"58","author":"Gubernot","year":"2015","journal-title":"Am. J. Ind. Med."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"402","DOI":"10.1136\/oemed-2016-103848","article-title":"Heat strain, volume depletion and kidney function in California agricultural workers","volume":"74","author":"Moyce","year":"2017","journal-title":"Occup. Environ. Med."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"200","DOI":"10.1080\/1059924X.2010.487021","article-title":"Preventing heat-related illness among agricultural workers","volume":"15","author":"Jackson","year":"2010","journal-title":"J. Agromed."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"315","DOI":"10.1097\/01.ede.0000208477.36665.34","article-title":"Vulnerability to Heat-Related Mortality","volume":"17","author":"Stafoggia","year":"2006","journal-title":"Epidemiology"},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"99","DOI":"10.1016\/j.maturitas.2011.03.008","article-title":"Heat wave impact on morbidity and mortality in the elderly population: A review of recent studies","volume":"69","author":"Bertil","year":"2011","journal-title":"Maturitas"},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"085001","DOI":"10.1289\/EHP556","article-title":"Opportunities and challenges for personal heat exposure research","volume":"125","author":"Kuras","year":"2017","journal-title":"Environ. Health Perspect."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"330","DOI":"10.1016\/j.autcon.2017.06.003","article-title":"Wristband-type wearable health devices to measure construction workers\u2019 physical demands","volume":"83","author":"Hwang","year":"2017","journal-title":"Autom. Constr."},{"key":"ref_21","doi-asserted-by":"crossref","first-page":"7772","DOI":"10.3390\/s100807772","article-title":"A Review of Accelerometry-Based Wearable Motion Detectors for Physical Activity Monitoring","volume":"10","author":"Yang","year":"2010","journal-title":"Sensors"},{"key":"ref_22","unstructured":"Sani, N.M., Mansor, W., Lee, K.Y., Zainudin, N.A., and Mahrim, S. (2015, January 26\u201328). Determination of heart rate from photoplethysmogram using Fast Fourier Transform. Proceedings of the 2015 International Conference on BioSignal Analysis, Processing and Systems (ICBAPS), Kuala Lumpur, Malaysia."},{"key":"ref_23","doi-asserted-by":"crossref","unstructured":"Mohan, P.M., Nisha, A.A., Nagarajan, V., and Jothi, E.S.J. (2016, January 6\u20138). Measurement of arterial oxygen saturation (SpO 2) using PPG optical sensor. Proceedings of the 2016 International Conference on Communication and Signal Processing (ICCSP), Melmaruvathur, India.","DOI":"10.1109\/ICCSP.2016.7754330"},{"key":"ref_24","doi-asserted-by":"crossref","first-page":"R1","DOI":"10.1088\/0967-3334\/28\/3\/R01","article-title":"Photoplethysmography and its application in clinical physiological measurement","volume":"28","author":"Allen","year":"2007","journal-title":"Physiol. Meas."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"969","DOI":"10.1007\/s10916-010-9505-0","article-title":"Relationship Between Measurement Site and Motion Artifacts in Wearable Reflected Photoplethysmography","volume":"35","author":"Maeda","year":"2010","journal-title":"J. Med. Syst."},{"key":"ref_26","doi-asserted-by":"crossref","first-page":"59","DOI":"10.1016\/S0735-6757(99)90019-0","article-title":"Pulse oximetry: Principles and limitations","volume":"17","author":"Sinex","year":"1999","journal-title":"Am. J. Emerg. Med."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"2017","DOI":"10.1007\/s00134-004-2399-x","article-title":"Pulse oximetry","volume":"30","author":"Jubran","year":"2004","journal-title":"Intensive Care Med."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"260","DOI":"10.1007\/s004210050245","article-title":"Accuracy of pulse oximetry during intense exercise under severe hypoxic conditions","volume":"76","author":"Benoit","year":"1997","journal-title":"Eur. J. Appl. Physiol."},{"key":"ref_29","doi-asserted-by":"crossref","first-page":"391","DOI":"10.3389\/fphys.2016.00391","article-title":"Comparative Analysis of the Equivital EQ02 Lifemonitor with Holter Ambulatory ECG Device for Continuous Measurement of ECG, Heart Rate, and Heart Rate Variability: A Validation Study for Precision and Accuracy","volume":"7","author":"Akintola","year":"2016","journal-title":"Front. Physiol."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"1538","DOI":"10.1109\/TBME.2014.2309951","article-title":"Unobtrusive Sensing and Wearable Devices for Health Informatics","volume":"61","author":"Zheng","year":"2014","journal-title":"IEEE Trans. Biomed. Eng."},{"key":"ref_31","doi-asserted-by":"crossref","unstructured":"Liu, W., Zhang, X., Wei, G., and Su, Z. (2018). Reduced graphene oxide-based double network polymeric hydrogels for pressure and temperature sensing. Sensors, 18.","DOI":"10.3390\/s18093162"},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"370","DOI":"10.1016\/j.snb.2005.03.037","article-title":"Galvanic decoupled sensor for monitoring biomass concentration during fermentation processes","volume":"111","author":"Hofmann","year":"2005","journal-title":"Sens. Actuators B. Chem."}],"container-title":["Sensors"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/3\/855\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T08:55:08Z","timestamp":1760172908000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/1424-8220\/20\/3\/855"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2020,2,6]]},"references-count":32,"journal-issue":{"issue":"3","published-online":{"date-parts":[[2020,2]]}},"alternative-id":["s20030855"],"URL":"https:\/\/doi.org\/10.3390\/s20030855","relation":{},"ISSN":["1424-8220"],"issn-type":[{"value":"1424-8220","type":"electronic"}],"subject":[],"published":{"date-parts":[[2020,2,6]]}}}