{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,6,26]],"date-time":"2026-06-26T15:34:30Z","timestamp":1782488070832,"version":"3.54.5"},"reference-count":39,"publisher":"Wiley","issue":"1","license":[{"start":{"date-parts":[[2020,7,20]],"date-time":"2020-07-20T00:00:00Z","timestamp":1595203200000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100009153","name":"University of Portsmouth","doi-asserted-by":"publisher","id":[{"id":"10.13039\/100009153","id-type":"DOI","asserted-by":"publisher"}]},{"DOI":"10.13039\/501100000765","name":"University College London","doi-asserted-by":"publisher","id":[{"id":"10.13039\/501100000765","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Experimental Physiology"],"published-print":{"date-parts":[[2021,1]]},"abstract":"<jats:sec><jats:title>New Findings<\/jats:title><jats:p><jats:list list-type=\"bullet\"><jats:list-item><jats:p><jats:bold>What is the central question of this study?<\/jats:bold><\/jats:p><jats:p>What is the physiological interpretation of<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0002.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0002\"\/>fluctuations observed during normobaric hypoxia in healthy individuals?<\/jats:p><\/jats:list-item><jats:list-item><jats:p><jats:bold>What is the main finding and its importance?<\/jats:bold><\/jats:p><jats:p>There is a significant flow of information between<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0003.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0003\"\/>and other cardio\u2010respiratory time series during graded hypoxia. Analysis of the pattern of<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0004.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0004\"\/>variations has potential for non\u2010invasive assessment of the engagement of respiratory control system in health and disease.<\/jats:p><\/jats:list-item><\/jats:list><\/jats:p><\/jats:sec><jats:sec><jats:title>Abstract<\/jats:title><jats:p>Peripheral capillary oxygen saturation (<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0005.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0005\"\/>) exhibits a complex pattern of fluctuations during hypoxia. The physiological interpretation of<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0006.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0006\"\/>variability is not well understood. In this study, we tested the hypothesis that<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0007.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0007\"\/>fluctuation carries information about integrated cardio\u2010respiratory control in healthy individuals using a network physiology approach. We explored the use of transfer entropy in order to compute the flow of information between cardio\u2010respiratory signals during hypoxia. Twelve healthy males (mean (SD) age 22 (4) years) were exposed to four simulated environments (fraction of inspired oxygen (<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0008.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0008\"\/>): 0.12, 0.145, 0.17, and 0.2093) for 45\u00a0min, in a single blind randomized controlled design. The flow of information between different physiological parameters (<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0009.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0009\"\/>, respiratory frequency, tidal volume, minute ventilation, heart rate, end\u2010tidal pressure of O<jats:sub>2<\/jats:sub>and CO<jats:sub>2<\/jats:sub>) were analysed using transfer entropy. Normobaric hypoxia was associated with a significant increase in entropy of the<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0010.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0010\"\/>time series. The transfer entropy analysis showed that, particularly at<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0011.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0011\"\/>0.145 and 0.12, the flow of information between<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0012.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0012\"\/>and other physiological variables exhibits a bidirectional relationship. While reciprocal interactions were observed between different cardio\u2010respiratory parameters during hypoxia,<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0013.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0013\"\/>remained the main hub of this network.<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0014.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0014\"\/>fluctuations during graded hypoxia exposure carry information about cardio\u2010respiratory control. Therefore,<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12815-math-0015.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12815:eph12815-math-0015\"\/>entropy analysis has the potential for non\u2010invasive assessment of the functional connectivity of respiratory control system in various healthcare settings.<\/jats:p><\/jats:sec>","DOI":"10.1113\/ep088755","type":"journal-article","created":{"date-parts":[[2020,7,9]],"date-time":"2020-07-09T06:36:23Z","timestamp":1594276583000},"page":"151-159","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":44,"title":["A network physiology approach to oxygen saturation variability during normobaric hypoxia"],"prefix":"10.1113","volume":"106","author":[{"given":"Yuji","family":"Jiang","sequence":"first","affiliation":[{"name":"Network Physiology Laboratory UCL Division of Medicine University College London London 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