{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,30]],"date-time":"2026-07-30T00:48:41Z","timestamp":1785372521163,"version":"3.55.0"},"reference-count":31,"publisher":"Wiley","issue":"4","license":[{"start":{"date-parts":[[2021,2,11]],"date-time":"2021-02-11T00:00:00Z","timestamp":1613001600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Experimental Physiology"],"published-print":{"date-parts":[[2021,4]]},"abstract":"<jats:sec><jats:title>New Findings<\/jats:title><jats:p><jats:list list-type=\"bullet\">\n<jats:list-item>\n<jats:p><jats:bold>What is the central question of this study?<\/jats:bold><\/jats:p>\n<jats:p>Does the ventilatory response to moderate acute hypoxia increase cerebral perfusion independently of changes in arterial oxygen tension in humans?<\/jats:p>\n<\/jats:list-item>\n<jats:list-item>\n<jats:p><jats:bold>What is the main finding and its importance?<\/jats:bold><\/jats:p>\n<jats:p>The ventilatory response does not increase middle cerebral artery mean blood velocity during moderate isocapnic acute hypoxia beyond that elicited by reduced oxygen saturation.<\/jats:p>\n<\/jats:list-item>\n<\/jats:list><\/jats:p><\/jats:sec><jats:sec><jats:title>Abstract<\/jats:title><jats:p>Hypoxia induces ventilatory, cardiovascular and cerebrovascular adjustments to defend against reductions in systemic oxygen delivery. We aimed to determine whether the ventilatory response to moderate acute hypoxia increases cerebral perfusion independently of changes in arterial oxygenation. Eleven young healthy individuals were exposed to four 15\u00a0min experimental conditions: (1) normoxia (partial pressure of end\u2010tidal oxygen, <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12949-math-0001.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12949:eph12949-math-0001\"\/>\u00a0=\u00a0100\u00a0mmHg), (2) hypoxia (<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12949-math-0002.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12949:eph12949-math-0002\"\/>\u00a0=\u00a050\u00a0mmHg), (3) normoxia with breathing volitionally matched to levels observed during hypoxia (hyperpnoea; <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12949-math-0003.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12949:eph12949-math-0003\"\/>\u00a0=\u00a0100\u00a0mmHg) and (4) hypoxia (<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12949-math-0004.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12949:eph12949-math-0004\"\/><jats:sub>\u00a0<\/jats:sub>=\u00a050\u00a0mmHg) with respiratory frequency and tidal volume volitionally matched to levels observed during normoxia (i.e., restricted breathing (RB)). Isocapnia was maintained in all conditions. Middle cerebral artery mean blood velocity (MCA <jats:italic>V<\/jats:italic><jats:sub>mean<\/jats:sub>), assessed by transcranial Doppler ultrasound, was increased during hypoxia (58\u00a0\u00b1\u00a012\u00a0cm\/s, <jats:italic>P<\/jats:italic>\u00a0=\u00a00.04) and hypoxia + RB (61\u00a0\u00b1\u00a014\u00a0cm\/s, <jats:italic>P<\/jats:italic>\u00a0&lt;\u00a00.001) compared to normoxia (55\u00a0\u00b1\u00a011\u00a0cm\/s), while it was unchanged during hyperpnoea (52\u00a0\u00b1\u00a013\u00a0cm\/s, <jats:italic>P<\/jats:italic>\u00a0=\u00a00.08). MCA <jats:italic>V<\/jats:italic><jats:sub>mean<\/jats:sub> was not different between hypoxia and hypoxia + RB (<jats:italic>P<\/jats:italic>\u00a0&gt;\u00a00.05). These findings suggest that the hypoxic ventilatory response does not increase cerebral perfusion, indexed using MCA <jats:italic>V<\/jats:italic><jats:sub>mean<\/jats:sub>, during moderate isocapnic acute hypoxia beyond that elicited by reduced oxygen saturation.<\/jats:p><\/jats:sec>","DOI":"10.1113\/ep089127","type":"journal-article","created":{"date-parts":[[2021,2,3]],"date-time":"2021-02-03T22:32:10Z","timestamp":1612391530000},"page":"861-867","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":4,"title":["The middle cerebral artery blood velocity response to acute normobaric hypoxia occurs independently of changes in ventilation in humans"],"prefix":"10.1113","volume":"106","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-7359-6528","authenticated-orcid":false,"given":"Sultan E.","family":"AlSalahi","sequence":"first","affiliation":[{"name":"School of Sport Exercise and Rehabilitation Sciences College of Life and Environmental Sciences University of Birmingham Edgbaston  Birmingham UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-0670-8339","authenticated-orcid":false,"given":"Rehan T.","family":"Junejo","sequence":"additional","affiliation":[{"name":"Department of Life Sciences Manchester Metropolitan University  Manchester UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chris","family":"Bradley","sequence":"additional","affiliation":[{"name":"School of Sport Exercise and Rehabilitation Sciences College of Life and Environmental Sciences University of Birmingham Edgbaston  Birmingham UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"George M.","family":"Balanos","sequence":"additional","affiliation":[{"name":"School of Sport Exercise and Rehabilitation Sciences College of Life and Environmental Sciences University of Birmingham Edgbaston  Birmingham UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Christoph","family":"Siebenmann","sequence":"additional","affiliation":[{"name":"Institute of Mountain Emergency Medicine EURAC Research  Bolzano Italy"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"James P.","family":"Fisher","sequence":"additional","affiliation":[{"name":"Department of Physiology Faculty of Medical &amp; Health Sciences University of Auckland  Auckland New Zealand"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2021,2,11]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00854.2014"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1113\/expphysiol.2008.045575"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0049074"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1113\/expphysiol.2005.030262"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1991.sp018824"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1186\/s13728-014-0021-6"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0127082"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1152\/jn.2002.88.3.1500"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00224.2017"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1097\/00000539-199710000-00018"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0034-5687(00)00125-0"},{"key":"e_1_2_9_13_1","doi-asserted-by":"publisher","DOI":"10.1002\/cphy.c140004"},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0034-5687(97)00050-9"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1172\/JCI101995"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.1152\/physrev.1994.74.3.543"},{"key":"e_1_2_9_17_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.01235.2009"},{"key":"e_1_2_9_18_1","doi-asserted-by":"publisher","DOI":"10.1113\/expphysiol.2013.076802"},{"key":"e_1_2_9_19_1","doi-asserted-by":"publisher","DOI":"10.1113\/expphysiol.2012.068015"},{"key":"e_1_2_9_20_1","doi-asserted-by":"publisher","DOI":"10.1523\/JNEUROSCI.1375-09.2009"},{"key":"e_1_2_9_21_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.neuroimage.2008.09.007"},{"key":"e_1_2_9_22_1","doi-asserted-by":"publisher","DOI":"10.1164\/ajrccm.163.4.2005057"},{"key":"e_1_2_9_23_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpheart.00894.2015"},{"key":"e_1_2_9_24_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.1993.sp019503"},{"key":"e_1_2_9_25_1","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1982.52.5.1358"},{"key":"e_1_2_9_26_1","doi-asserted-by":"publisher","DOI":"10.1113\/JP279751"},{"key":"e_1_2_9_27_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.tins.2012.11.004"},{"key":"e_1_2_9_28_1","doi-asserted-by":"publisher","DOI":"10.1378\/chest.128.1.345"},{"key":"e_1_2_9_29_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jneumeth.2011.01.011"},{"key":"e_1_2_9_30_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2012.228551"},{"key":"e_1_2_9_31_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2013.268953"},{"key":"e_1_2_9_32_1","doi-asserted-by":"publisher","DOI":"10.1038\/jcbfm.2011.81"}],"container-title":["Experimental Physiology"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/EP089127","content-type":"application\/pdf","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/onlinelibrary.wiley.com\/doi\/full-xml\/10.1113\/EP089127","content-type":"application\/xml","content-version":"vor","intended-application":"text-mining"},{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/pdf\/10.1113\/EP089127","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2023,9,1]],"date-time":"2023-09-01T17:47:56Z","timestamp":1693590476000},"score":1,"resource":{"primary":{"URL":"https:\/\/physoc.onlinelibrary.wiley.com\/doi\/10.1113\/EP089127"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2021,2,11]]},"references-count":31,"journal-issue":{"issue":"4","published-print":{"date-parts":[[2021,4]]}},"alternative-id":["10.1113\/EP089127"],"URL":"https:\/\/doi.org\/10.1113\/ep089127","archive":["Portico"],"relation":{},"ISSN":["0958-0670","1469-445X"],"issn-type":[{"value":"0958-0670","type":"print"},{"value":"1469-445X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2021,2,11]]},"assertion":[{"value":"2020-09-30","order":0,"name":"received","label":"Received","group":{"name":"publication_history","label":"Publication History"}},{"value":"2021-01-28","order":1,"name":"accepted","label":"Accepted","group":{"name":"publication_history","label":"Publication History"}},{"value":"2021-02-11","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}