{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,13]],"date-time":"2026-05-13T01:23:21Z","timestamp":1778635401880,"version":"3.51.4"},"reference-count":71,"publisher":"Wiley","issue":"7","license":[{"start":{"date-parts":[[2024,5,15]],"date-time":"2024-05-15T00:00:00Z","timestamp":1715731200000},"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":[[2024,7]]},"abstract":"<jats:sec><jats:title>Abstract<\/jats:title><jats:p>High altitude (HA) ascent imposes systemic hypoxia and associated risk of acute mountain sickness. Acute hypoxia elicits a hypoxic ventilatory response (HVR), which is augmented with chronic HA exposure (i.e., ventilatory acclimatization; VA). However, laboratory\u2010based HVR tests lack portability and feasibility in field studies. As an alternative, we aimed to characterize area under the curve (AUC) calculations on Fenn diagrams, modified by plotting portable measurements of end\u2010tidal carbon dioxide () against peripheral oxygen saturation () to characterize and quantify VA during incremental ascent to HA (<jats:italic>n<\/jats:italic>\u00a0=\u00a046). Secondarily, these participants were compared with a separate group following the identical ascent profile whilst self\u2010administering a prophylactic oral dose of acetazolamide (Az; 125\u00a0mg BID; <jats:italic>n<\/jats:italic>\u00a0=\u00a020) during ascent. First, morning  and  measurements were collected on 46 acetazolamide\u2010free (NAz) lowland participants during an incremental ascent over 10\u00a0days to 5160\u00a0m in the Nepal Himalaya. AUC was calculated from individually constructed Fenn diagrams, with a trichotomized split on ranked values characterizing the smallest, medium, and largest magnitudes of AUC, representing high (<jats:italic>n<\/jats:italic>\u00a0=\u00a015), moderate (<jats:italic>n<\/jats:italic>\u00a0=\u00a016), and low (<jats:italic>n<\/jats:italic>\u00a0=\u00a015) degrees of acclimatization. After characterizing the range of response magnitudes, we further demonstrated that AUC magnitudes were significantly smaller in the Az group compared to the NAz group (<jats:italic>P\u00a0<\/jats:italic>=\u00a00.0021), suggesting improved VA. These results suggest that calculating AUC on modified Fenn diagrams has utility in assessing VA in large groups of trekkers during incremental ascent to HA, due to the associated portability and congruency with known physiology, although this novel analytical method requires further validation in controlled experiments.<\/jats:p><\/jats:sec><jats:sec><jats:title>Highlights<\/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><jats:p>What are the characteristics of a novel methodological approach to assess ventilatory acclimatization (VA) with incremental ascent to high altitude (HA)?<\/jats:p><\/jats:list-item>\n<jats:list-item><jats:p><jats:bold>What is the main finding and its importance?<\/jats:bold><\/jats:p><jats:p>Area under the curve (AUC) magnitudes calculated from modified Fenn diagrams were significantly smaller in trekkers taking an oral prophylactic dose of acetazolamide compared to an acetazolamide\u2010free group, suggesting improved VA. During incremental HA ascent, quantifying AUC using modified Fenn diagrams is feasible to assess VA in large groups of trekkers with ascent, although this novel analytical method requires further validation in controlled experiments.<\/jats:p><\/jats:list-item>\n<\/jats:list><\/jats:p><\/jats:sec>","DOI":"10.1113\/ep091748","type":"journal-article","created":{"date-parts":[[2024,5,15]],"date-time":"2024-05-15T09:00:07Z","timestamp":1715763607000},"page":"1080-1098","update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":6,"title":["Using modified Fenn diagrams to assess ventilatory acclimatization during ascent to high altitude: Effect of acetazolamide"],"prefix":"10.1113","volume":"109","author":[{"given":"Rodion","family":"Isakovich","sequence":"first","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Valerie C.","family":"Cates","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Brandon A.","family":"Pentz","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jordan D.","family":"Bird","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emily R.","family":"Vanden Berg","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Emily M.","family":"de Freitas","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Cassandra E.","family":"Nysten","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Jack K.","family":"Leacy","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"},{"name":"Department of Physiology, School of Medicine, College of Medicine &amp; Health University Cork College  Cork Ireland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8832-1153","authenticated-orcid":false,"given":"Ken D.","family":"O'Halloran","sequence":"additional","affiliation":[{"name":"Department of Physiology, School of Medicine, College of Medicine &amp; Health University Cork College  Cork Ireland"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Thomas D.","family":"Brutsaert","sequence":"additional","affiliation":[{"name":"Department of Exercise Science Syracuse University  Syracuse New York USA"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"given":"Mingma T.","family":"Sherpa","sequence":"additional","affiliation":[{"name":"Kunde Hospital  Khunde, Solukhumbu Nepal"}],"role":[{"role":"author","vocabulary":"crossref"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7102-4235","authenticated-orcid":false,"given":"Trevor A.","family":"Day","sequence":"additional","affiliation":[{"name":"Department of Biology, Faculty of Science and Technology Mount Royal University  Calgary Alberta Canada"}],"role":[{"role":"author","vocabulary":"crossref"}]}],"member":"311","published-online":{"date-parts":[[2024,5,15]]},"reference":[{"key":"e_1_2_9_2_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.resp.2013.05.020"},{"key":"e_1_2_9_3_1","doi-asserted-by":"publisher","DOI":"10.1089\/152702903321488979"},{"key":"e_1_2_9_4_1","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2006.7.17"},{"key":"e_1_2_9_5_1","doi-asserted-by":"publisher","DOI":"10.1183\/09031936.06.00015805"},{"key":"e_1_2_9_6_1","doi-asserted-by":"publisher","DOI":"10.1089\/152702903769192296"},{"key":"e_1_2_9_7_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00363.2021"},{"key":"e_1_2_9_8_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00973.2020"},{"key":"e_1_2_9_9_1","doi-asserted-by":"publisher","DOI":"10.1007\/978-3-319-91137-3_2"},{"key":"e_1_2_9_10_1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1440-1843.2004.00576.x"},{"key":"e_1_2_9_11_1","doi-asserted-by":"publisher","DOI":"10.1007\/s00484-022-02298-y"},{"key":"e_1_2_9_12_1","doi-asserted-by":"publisher","DOI":"10.14814\/phy2.15521"},{"key":"e_1_2_9_13_1","doi-asserted-by":"publisher","DOI":"10.1080\/00207238508710201"},{"key":"e_1_2_9_14_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.jsams.2010.02.001"},{"key":"e_1_2_9_15_1","doi-asserted-by":"publisher","DOI":"10.1097\/MAJ.0b013e3181629a32"},{"key":"e_1_2_9_16_1","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1999.87.2.817"},{"key":"e_1_2_9_17_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajplegacy.1946.146.5.637"},{"key":"e_1_2_9_18_1","doi-asserted-by":"publisher","DOI":"10.1152\/jappl.1975.38.6.1067"},{"key":"e_1_2_9_19_1","doi-asserted-by":"publisher","DOI":"10.1186\/s40064-016-3313-z"},{"key":"e_1_2_9_20_1","doi-asserted-by":"publisher","DOI":"10.1016\/0002-9343(55)90344-2"},{"key":"e_1_2_9_21_1","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2006.7.64"},{"key":"e_1_2_9_22_1","doi-asserted-by":"publisher","DOI":"10.1152\/physiol.00018.2014"},{"key":"e_1_2_9_23_1","doi-asserted-by":"publisher","DOI":"10.1038\/ki.1975.130"},{"key":"e_1_2_9_24_1","doi-asserted-by":"publisher","DOI":"10.1371\/journal.pone.0168930"},{"key":"e_1_2_9_25_1","doi-asserted-by":"publisher","DOI":"10.1136\/bjsm.36.2.141"},{"key":"e_1_2_9_26_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJMoa0801581"},{"key":"e_1_2_9_27_1","doi-asserted-by":"publisher","DOI":"10.2215\/CJN.07400715"},{"key":"e_1_2_9_28_1","doi-asserted-by":"publisher","DOI":"10.1113\/EP088571"},{"key":"e_1_2_9_29_1","doi-asserted-by":"publisher","DOI":"10.3389\/fphys.2019.01075"},{"key":"e_1_2_9_30_1","doi-asserted-by":"publisher","DOI":"10.1152\/japplphysiol.00973.2004"},{"key":"e_1_2_9_31_1","doi-asserted-by":"publisher","DOI":"10.1113\/jphysiol.2008.154716"},{"key":"e_1_2_9_32_1","doi-asserted-by":"publisher","DOI":"10.1016\/j.resp.2016.10.012"},{"key":"e_1_2_9_33_1","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2005.6.50"},{"key":"e_1_2_9_34_1","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2014.1058"},{"key":"e_1_2_9_35_1","doi-asserted-by":"publisher","DOI":"10.1056\/NEJM199105163242003"},{"key":"e_1_2_9_36_1","first-page":"2529","article-title":"Steady\u2010state cerebral blood flow regulation at altitude: Interaction between oxygen and carbon dioxide","volume":"119","author":"Lafave H. 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