{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,29]],"date-time":"2026-10-29T08:42:03Z","timestamp":1793263323779,"version":"4.5.0"},"reference-count":52,"publisher":"Wiley","issue":"10","license":[{"start":{"date-parts":[[2019,7,25]],"date-time":"2019-07-25T00:00:00Z","timestamp":1564012800000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/onlinelibrary.wiley.com\/termsAndConditions#vor"}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Experimental Physiology"],"published-print":{"date-parts":[[2019,10]]},"abstract":"<jats:sec><jats:title>New Findings<\/jats:title><jats:p><jats:list list-type=\"bullet\">\n<jats:list-item><jats:p><jats:bold>What is the central question of this study?<\/jats:bold><\/jats:p>\n<jats:p>What are the independent effects of hypoxia and hypocapnia on cerebral haemodynamics and cognitive function?<\/jats:p>\n<\/jats:list-item>\n<jats:list-item><jats:p><jats:bold>What is the main finding and its importance?<\/jats:bold><\/jats:p>\n<jats:p>Exposure to hyperventilation\u2010induced hypocapnia causes cognitive impairment in both normoxia and hypoxia. In addition, supplementation of carbon dioxide during hypoxia alleviates the cognitive impairment and reverses hypocapnia\u2010induced vasoconstriction of the cerebrovasculature. These data provide new evidence for the independent effect of hypocapnia on the cognitive impairment associated with hypoxia.<\/jats:p>\n<\/jats:list-item>\n<\/jats:list><\/jats:p><\/jats:sec><jats:sec><jats:title>Abstract<\/jats:title><jats:p>Hypoxia, which is accompanied by hypocapnia at altitude, is associated with cognitive impairment. This study examined the independent effects of hypoxia and hypocapnia on cognitive function and assessed how changes in cerebral haemodynamics may underpin cognitive performance outcomes. Single reaction time (SRT), five\u2010choice reaction time (CRT) and spatial working memory (SWM) tasks were completed in 20 participants at rest and after 1\u00a0h of isocapnic hypoxia (IH, end\u2010tidal oxygen partial pressure (<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12550-math-0001.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12550:eph12550-math-0001\"\/>)\u00a0=\u00a045\u00a0mmHg, end\u2010tidal carbon dioxide partial pressure (<jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12550-math-0002.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12550:eph12550-math-0002\"\/>) clamped at normal) and poikilocapnic hypoxia (PH, <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12550-math-0003.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12550:eph12550-math-0003\"\/>\u00a0=\u00a045\u00a0mmHg, <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12550-math-0004.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12550:eph12550-math-0004\"\/> not clamped). A subgroup of 10 participants were also exposed to euoxic hypocapnia (EH, <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12550-math-0005.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12550:eph12550-math-0005\"\/>\u00a0=\u00a0100\u00a0mmHg, <jats:inline-graphic xmlns:xlink=\"http:\/\/www.w3.org\/1999\/xlink\" xlink:href=\"graphic\/eph12550-math-0006.png\" xlink:title=\"urn:x-wiley:09580670:media:eph12550:eph12550-math-0006\"\/> clamped 8\u00a0mmHg below normal). Middle cerebral artery velocity (MCAv) and prefrontal cerebral haemodynamics were measured with transcranial Doppler and near infrared spectroscopy, respectively. IH did not affect SRT and CRT performance from rest (566\u00a0\u00b1\u00a050 and 594\u00a0\u00b1\u00a070\u00a0ms), whereas PH (721\u00a0\u00b1\u00a051 and 765\u00a0\u00b1\u00a048\u00a0ms) and EH (718\u00a0\u00b1\u00a055 and 755\u00a0\u00b1\u00a034\u00a0ms) slowed response times (<jats:italic>P<\/jats:italic>\u00a0&lt;\u00a00.001\u00a0<jats:italic>vs<\/jats:italic>. IH). Performance on the SWM task was not altered by condition. MCAv increased during IH compared to PH (<jats:italic>P<\/jats:italic>\u00a0&lt;\u00a00.05), which was unchanged from rest. EH caused a significant fall in MCAv and prefrontal cerebral oxygenation (<jats:italic>P<\/jats:italic>\u00a0&lt;\u00a00.05\u00a0<jats:italic>vs<\/jats:italic>. baseline). MCAv was moderately correlated to cognitive performance (<jats:italic>R<\/jats:italic><jats:sup>2<\/jats:sup>\u00a0=\u00a00.266\u20130.289), whereas prefrontal cerebral tissue perfusion and saturation were not (<jats:italic>P<\/jats:italic>\u00a0&gt;\u00a00.05). These findings reveal a role of hyperventilation\u2010induced hypocapnia <jats:italic>per se<\/jats:italic> on the development of cognitive impairment during normoxic <jats:italic>and<\/jats:italic> hypoxic exposures.<\/jats:p><\/jats:sec>","DOI":"10.1113\/ep087602","type":"journal-article","created":{"date-parts":[[2019,7,25]],"date-time":"2019-07-25T08:38:45Z","timestamp":1564043925000},"page":"1482-1493","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":36,"title":["Isolating the independent effects of hypoxia and hyperventilation\u2010induced hypocapnia on cerebral haemodynamics and cognitive function"],"prefix":"10.1113","volume":"104","author":[{"ORCID":"https:\/\/orcid.org\/0000-0001-9533-5732","authenticated-orcid":false,"given":"Alexander T.","family":"Friend","sequence":"first","affiliation":[{"name":"School of Sport Exercise and Rehabilitation Sciences University of Birmingham  Edgbaston UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"George M.","family":"Balanos","sequence":"additional","affiliation":[{"name":"School of Sport Exercise and Rehabilitation Sciences University of Birmingham  Edgbaston UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Samuel J.E.","family":"Lucas","sequence":"additional","affiliation":[{"name":"School of Sport Exercise and Rehabilitation Sciences University of Birmingham  Edgbaston UK"},{"name":"Centre for Human Brain Health University of Birmingham  Edgbaston UK"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2019,7,25]]},"reference":[{"key":"e_1_2_10_2_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00854.2014"},{"key":"e_1_2_10_3_1","doi-asserted-by":"publisher","DOI":"10.1113\/expphysiol.2008.045575"},{"key":"e_1_2_10_4_1","doi-asserted-by":"publisher","DOI":"10.1042\/CS20130343"},{"key":"e_1_2_10_5_1","doi-asserted-by":"publisher","DOI":"10.3357\/ASEM.3661.2013"},{"key":"e_1_2_10_6_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00069.2007"},{"key":"e_1_2_10_7_1","doi-asserted-by":"publisher","DOI":"10.1111\/1469-8986.3740418"},{"key":"e_1_2_10_8_1","doi-asserted-by":"publisher","DOI":"10.1097\/PSY.0b013e3181e68e94"},{"key":"e_1_2_10_9_1","doi-asserted-by":"publisher","DOI":"10.1113\/EP085764"},{"key":"e_1_2_10_10_1","doi-asserted-by":"publisher","DOI":"10.1080\/23279095.2017.1286346"},{"key":"e_1_2_10_11_1","doi-asserted-by":"publisher","DOI":"10.1183\/20734735.001415"},{"key":"e_1_2_10_12_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00285.2014"},{"key":"e_1_2_10_13_1","doi-asserted-by":"publisher","DOI":"10.1007\/s10877-016-9942-5"},{"key":"e_1_2_10_14_1","doi-asserted-by":"publisher","DOI":"10.1016\/S0140-6736(16)00421-9"},{"key":"e_1_2_10_15_1","doi-asserted-by":"publisher","DOI":"10.1089\/neu.2014.3748"},{"key":"e_1_2_10_16_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.physbeh.2016.06.001"},{"key":"e_1_2_10_17_1","doi-asserted-by":"publisher","DOI":"10.1037\/a0018502"},{"key":"e_1_2_10_18_1","doi-asserted-by":"publisher","DOI":"10.1093\/geronb\/59.6.P285"},{"key":"e_1_2_10_19_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1469-8986.1991.tb00413.x"},{"key":"e_1_2_10_20_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM200107123450206"},{"key":"e_1_2_10_21_1","doi-asserted-by":"publisher","DOI":"10.1172\/JCI101680"},{"key":"e_1_2_10_22_1","doi-asserted-by":"publisher","DOI":"10.1172\/JCI101995"},{"issue":"7","key":"e_1_2_10_23_1","first-page":"639","article-title":"Changes in brain activation patterns according to cross\u2010training effect in serial reaction time task: An functional MRI study","volume":"8","author":"Kwon Y. 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