{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T14:49:53Z","timestamp":1791470993206,"version":"4.3.4"},"reference-count":51,"publisher":"Wiley","license":[{"start":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T00:00:00Z","timestamp":1791417600000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T00:00:00Z","timestamp":1791417600000},"content-version":"tdm","delay-in-days":0,"URL":"http:\/\/doi.wiley.com\/10.1002\/tdm_license_1.1"}],"content-domain":{"domain":["physoc.onlinelibrary.wiley.com"],"crossmark-restriction":true},"short-container-title":["Experimental Physiology"],"abstract":"<jats:title>Abstract<\/jats:title>\n                  <jats:p>\n                    Exogenous ketosis induced by ketone ester (KE) ingestion has attracted growing interest as a potential strategy to enhance physiological tolerance to reduced O\n                    <jats:sub>2<\/jats:sub>\n                    availability. Reported benefits arise largely from KE\u2010induced hyperventilation, which can improve systemic and tissue oxygenation during altitude exposure and hypoxic exercise, potentially complemented by favourable effects on cellular bioenergetics. Whether these responses translate to breath\u2010hold diving, however, remains unknown. Breath\u2010hold performance is constrained by the integrated effects of progressive hypoxaemia, CO\n                    <jats:sub>2<\/jats:sub>\n                    accumulation, acid\u2013base disturbance, altered cerebrovascular regulation and chemoreflex\u2010mediated respiratory drive. Because ventilation ceases during apnoea, interventions that alter pre\u2010apnoeic acid\u2013base status or CO\n                    <jats:sub>2<\/jats:sub>\n                    signalling might modify the chemical, neural and perceptual stimuli underlying the urge to breathe without slowing O\n                    <jats:sub>2<\/jats:sub>\n                    depletion. Safety therefore depends not only on preserving cerebral O\n                    <jats:sub>2<\/jats:sub>\n                    delivery, but also on maintaining the chemoreflex and perceptual warning signals that ordinarily precede hypoxic loss of consciousness. This review evaluates whether the established physiological effects of KE are mechanistically compatible with the unique demands of apnoea, focusing on acid\u2013base regulation, CO\n                    <jats:sub>2<\/jats:sub>\n                    \u2010dependent cerebrovascular control, autonomic integration and training\u2010related adaptations in elite freedivers, including reduced chemoreflex sensitivity and enhanced cortical control of respiratory drive. We propose that benefits observed during maintained ventilation might not translate to breath\u2010hold diving and could create a mechanistic mismatch with uncertain consequences for performance and safety. Direct apnoea\u2010specific studies are required to determine whether KE supplementation is beneficial, neutral or harmful.\n                  <\/jats:p>","DOI":"10.1113\/ep094163","type":"journal-article","created":{"date-parts":[[2026,10,8]],"date-time":"2026-10-08T13:53:51Z","timestamp":1791467631000},"update-policy":"https:\/\/doi.org\/10.1002\/crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Exogenous ketosis in breath\u2010hold diving: Promise, paradox and physiological risk"],"prefix":"10.1113","author":[{"given":"Ivan","family":"Drvi\u0161","sequence":"first","affiliation":[{"name":"Faculty of Kinesiology University of Zagreb  Zagreb Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-8659-6965","authenticated-orcid":false,"given":"Myrthe","family":"Stalmans","sequence":"additional","affiliation":[{"name":"Department of Cellular and Physiological Sciences, Faculty of Medicine University of British Columbia  Kelowna British Columbia Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-1259-6230","authenticated-orcid":false,"given":"Dario","family":"Vrdoljak","sequence":"additional","affiliation":[{"name":"Centre for Heart, Lung and Vascular Health University of British Columbia, Okanagan Campus  Kelowna British Columbia Canada"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Nikola","family":"Foretic","sequence":"additional","affiliation":[{"name":"Faculty of Kinesiology University of Split  Split Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-0498-7095","authenticated-orcid":false,"given":"Damian M.","family":"Bailey","sequence":"additional","affiliation":[{"name":"Neurovascular Research Laboratory, Faculty of Life Sciences and Education University of South Wales  Pontypridd UK"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"\u017deljko","family":"Duji\u0107","sequence":"additional","affiliation":[{"name":"Department of Integrative Physiology University of Split School of Medicine  Split Croatia"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"311","published-online":{"date-parts":[[2026,10,8]]},"reference":[{"key":"e_1_2_14_2_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.91008.2008"},{"key":"e_1_2_14_3_1","doi-asserted-by":"publisher","DOI":"10.1089\/ham.2013.1138"},{"key":"e_1_2_14_4_1","doi-asserted-by":"publisher","DOI":"10.1177\/0271678X16686093"},{"key":"e_1_2_14_5_1","doi-asserted-by":"publisher","DOI":"10.1113\/JP272404"},{"key":"e_1_2_14_6_1","doi-asserted-by":"publisher","DOI":"10.1096\/fj.201701031R"},{"key":"e_1_2_14_7_1","doi-asserted-by":"publisher","DOI":"10.1113\/EP086269"},{"key":"e_1_2_14_8_1","doi-asserted-by":"publisher","DOI":"10.1152\/ajpregu.00271.2015"},{"key":"e_1_2_14_9_1","doi-asserted-by":"publisher","DOI":"10.1113\/JP285555"},{"issue":"5","key":"e_1_2_14_10_1","doi-asserted-by":"crossref","first-page":"497","DOI":"10.1123\/ijsnem.2017-0300","article-title":"The effect of a dietary nitrate supplementation in the form of a single shot of beetroot juice on static and dynamic apnea performance","volume":"28","author":"Barlow M. 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