{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,5,14]],"date-time":"2026-05-14T20:52:29Z","timestamp":1778791949095,"version":"3.51.4"},"reference-count":27,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2024,7,31]],"date-time":"2024-07-31T00:00:00Z","timestamp":1722384000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Physiol."],"abstract":"<jats:sec><jats:title>Introduction<\/jats:title><jats:p>Elite breath-hold divers (BHD) possess several oxygen conserving adaptations to endure long dives similar to diving mammals. During dives, Bottlenose Dolphins may increase the alveolar ventilation (V<jats:sub>A<\/jats:sub>) to perfusion (Q) ratio to increase alveolar oxygen delivery. We hypothesized that BHD possess similar adaptive mechanisms during apnea.<\/jats:p><\/jats:sec><jats:sec><jats:title>Methods and results<\/jats:title><jats:p>Pulmonary blood volume (PBV) was determined by echocardiography, <jats:sup>15<\/jats:sup>O-H<jats:sub>2<\/jats:sub>O PET\/CT, and cardiac MRi, (n = 6) during and after maximum apneas. Pulmonary function was determined by body box spirometry and compared to matched controls. After 2\u00a0min of apnea, the PBV determined by echocardiography and <jats:sup>15<\/jats:sup>O-H<jats:sub>2<\/jats:sub>O-PET\/CT decreased by 26% and 41%, respectively. After 4\u00a0min of apnea, the PBV assessed by echocardiography and cardiac MRi decreased by 48% and 67%, respectively (n = 6). Fractional saturation (F)O<jats:sub>2<\/jats:sub>Hb determined by arterial blood-gas-analyses collected after warm-up and a 5-minute pool-apnea (n = 9) decreased by 43%. Compared to matched controls (n = 8), spirometry revealed a higher total and alveolar-lung-capacity in BHD (n = 9), but a lower diffusion-constant.<\/jats:p><\/jats:sec><jats:sec><jats:title>Conclusion<\/jats:title><jats:p>Our results contrast with previous studies, that demonstrated similar lung gas transfer in BHD and matched controls. We conclude that elite BHD 1) have a lower diffusion constant than matched controls, and 2) gradually decrease PBV during apnea and in turn increase V<jats:sub>A<\/jats:sub>\/Q to increase alveolar oxygen delivery during maximum apnea. We suggest that BHD possess pulmonary adaptations similar to diving mammals to tolerate decreasing tissue oxygenation.<\/jats:p><\/jats:sec><jats:sec><jats:title>New and noteworthy<\/jats:title><jats:p>This manuscript addresses novel knowledge on tolerance to hypoxia during diving, which is shared by elite breath-hold divers and adult diving mammals: Our study indicates that elite breath-hold divers gradually decrease pulmonary blood volume and in turn increase VA\/Q, to increase alveolar oxygen delivery during maximum apnea to tolerate decreasing oxygen levels similar to the Bottlenose Dolphin.<\/jats:p><\/jats:sec>","DOI":"10.3389\/fphys.2024.1296537","type":"journal-article","created":{"date-parts":[[2024,7,31]],"date-time":"2024-07-31T10:26:36Z","timestamp":1722421596000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":3,"title":["Pulmonary vascular adaptations to hypoxia in elite breath-hold 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work","author":"Astrand","year":"1954","journal-title":"J.Appl.Physiol,"},{"key":"B2","first-page":"343","article-title":"Factors influencing tolerance of cardiac muscle to hypoxia","author":"Bing","year":"1975","journal-title":"Recent Adv.Stud.Cardiac.Struct.Metab"},{"key":"B3","first-page":"2947","article-title":"High fatty acid oxidation capacity and phosphorylation control despite elevated leak and reduced respiratory capacity in northern elephant seal muscle mitochondria","author":"Chicco","year":"2014","journal-title":"J Exp.Biol."},{"key":"B4","doi-asserted-by":"crossref","first-page":"1113","DOI":"10.1183\/09031936.00118807","article-title":"Lung hyperinflation: foe or friend?","author":"Eichinger","year":"2008","journal-title":"Eur.Respir.J."},{"key":"B5","doi-asserted-by":"crossref","first-page":"838","DOI":"10.3389\/fphys.2018.00838","article-title":"Modeling Tissue and Blood Gas Kinetics in Coastal and Offshore Common Bottlenose Dolphins, Tursiops 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