1
|
Kjeld T, Krag TO, Brenøe A, Møller AM, Arendrup HC, Højberg J, Fuglø D, Hancke S, Tolbod LP, Gormsen LC, Vissing J, Hansen EG. Hemoglobin concentration and blood shift during dry static apnea in elite breath hold divers. Front Physiol 2024; 15:1305171. [PMID: 38745836 PMCID: PMC11092981 DOI: 10.3389/fphys.2024.1305171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Accepted: 01/23/2024] [Indexed: 05/16/2024] Open
Abstract
Introduction Elite breath-hold divers (BHD) enduring apneas of more than 5 min are characterized by tolerance to arterial blood oxygen levels of 4.3 kPa and low oxygen-consumption in their hearts and skeletal muscles, similar to adult seals. Adult seals possess an adaptive higher hemoglobin-concentration and Bohr effect than pups, and when sedated, adult seals demonstrate a blood shift from the spleen towards the brain, lungs, and heart during apnea. We hypothesized these observations to be similar in human BHD. Therefore, we measured hemoglobin- and 2,3-biphosphoglycerate-concentrations in BHD (n = 11) and matched controls (n = 11) at rest, while myocardial mass, spleen and lower extremity volumes were assessed at rest and during apnea in BHD. Methods and results After 4 min of apnea, left ventricular myocardial mass (LVMM) determined by 15O-H2O-PET/CT (n = 6) and cardiac MRI (n = 6), was unaltered compared to rest. During maximum apnea (∼6 min), lower extremity volume assessed by DXA-scan revealed a ∼268 mL decrease, and spleen volume, assessed by ultrasonography, decreased ∼102 mL. Compared to age, BMI and VO2max matched controls (n = 11), BHD had similar spleen sizes and 2,3- biphosphoglycerate-concentrations, but higher total hemoglobin-concentrations. Conclusion Our results indicate: 1) Apnea training in BHD may increase hemoglobin concentration as an oxygen conserving adaptation similar to adult diving mammals. 2) The blood shift during dry apnea in BHD is 162% more from the lower extremities than from the spleen. 3) In contrast to the previous theory of the blood shift demonstrated in sedated adult seals, blood shift is not towards the heart during dry apnea in humans.
Collapse
Affiliation(s)
- Thomas Kjeld
- Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Thomas O. Krag
- Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Anders Brenøe
- Department of Clinical Medicine, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Ann Merete Møller
- Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | | | - Jens Højberg
- Department of Cardiothoracic Anesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Dan Fuglø
- Department of Nuclear Medicine, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Søren Hancke
- Department of Clinical Medicine, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Lars Poulsen Tolbod
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Lars Christian Gormsen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - John Vissing
- Copenhagen Neuromuscular Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Egon Godthaab Hansen
- Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
2
|
Kjeld T, Isbrand AB, Linnet K, Zerahn B, Højberg J, Hansen EG, Gormsen LC, Bejder J, Krag T, Vissing J, Bøtker HE, Arendrup HC. Extreme Hypoxia Causing Brady-Arrythmias During Apnea in Elite Breath-Hold Divers. Front Physiol 2021; 12:712573. [PMID: 34925050 PMCID: PMC8678416 DOI: 10.3389/fphys.2021.712573] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 09/27/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction: The cardiac electrical conduction system is very sensitive to hypoglycemia and hypoxia, and the consequence may be brady-arrythmias. Weddell seals endure brady-arrythmias during their dives when desaturating to 3.2 kPa and elite breath-hold-divers (BHD), who share metabolic and cardiovascular adaptions including bradycardia with diving mammals, endure similar desaturation during maximum apnea. We hypothesized that hypoxia causes brady-arrythmias during maximum apnea in elite BHD. Hence, this study aimed to define the arterial blood glucose (Glu), peripheral saturation (SAT), heart rhythm (HR), and mean arterial blood pressure (MAP) of elite BHD during maximum apneas. Methods: HR was monitored with Direct-Current-Pads/ECG-lead-II and MAP and Glu from a radial arterial-catheter in nine BHD performing an immersed and head-down maximal static pool apnea after three warm-up apneas. SAT was monitored with a sensor on the neck of the subjects. On a separate day, a 12-lead-ECG-monitored maximum static apnea was repeated dry (n = 6). Results: During pool apnea of maximum duration (385 ± 70 s), SAT decreased from 99.6 ± 0.5 to 58.5 ± 5.5% (∼PaO2 4.8 ± 1.5 kPa, P < 0.001), while Glu increased from 5.8 ± 0.2 to 6.2 ± 0.2 mmol/l (P = 0.009). MAP increased from 103 ± 4 to 155 ± 6 mm Hg (P < 0.005). HR decreased to 46 ± 10 from 86 ± 14 beats/minute (P < 0.001). HR and MAP were unchanged after 3–4 min of apnea. During dry apnea (378 ± 31 s), HR decreased from 55 ± 4 to 40 ± 3 beats/minute (P = 0.031). Atrioventricular dissociation and junctional rhythm were observed both during pool and dry apneas. Conclusion: Our findings contrast with previous studies concluding that Glu decreases during apnea diving. We conclude during maximum apnea in elite BHD that (1) the diving reflex is maximized after 3–4 min, (2) increasing Glu may indicate lactate metabolism in accordance with our previous results, and (3) extreme hypoxia rather than hypoglycemia causes brady-arrythmias in elite BHD similar to diving mammals.
Collapse
Affiliation(s)
- Thomas Kjeld
- Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Anders Brenøe Isbrand
- Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Katrine Linnet
- Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Bo Zerahn
- Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Jens Højberg
- Department of Cardiothoracic Anesthesiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Egon Godthaab Hansen
- Department of Anesthesiology, Herlev Hospital, University of Copenhagen, Copenhagen, Denmark
| | - Lars Christian Gormsen
- Department of Clinical Physiology and Nuclear Medicine, Skejby Hospital, Aarhus University, Aarhus, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sports (NEXS), University of Copenhagen, Copenhagen, Denmark
| | - Thomas Krag
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - John Vissing
- Department of Neurology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Hans Erik Bøtker
- Department of Cardiology, Aarhus University Hospital, Aarhus, Denmark
| | | |
Collapse
|
3
|
Patrician A, Dujić Ž, Spajić B, Drviš I, Ainslie PN. Breath-Hold Diving - The Physiology of Diving Deep and Returning. Front Physiol 2021; 12:639377. [PMID: 34093221 PMCID: PMC8176094 DOI: 10.3389/fphys.2021.639377] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 04/07/2021] [Indexed: 11/13/2022] Open
Abstract
Breath-hold diving involves highly integrative physiology and extreme responses to both exercise and asphyxia during progressive elevations in hydrostatic pressure. With astonishing depth records exceeding 100 m, and up to 214 m on a single breath, the human capacity for deep breath-hold diving continues to refute expectations. The physiological challenges and responses occurring during a deep dive highlight the coordinated interplay of oxygen conservation, exercise economy, and hyperbaric management. In this review, the physiology of deep diving is portrayed as it occurs across the phases of a dive: the first 20 m; passive descent; maximal depth; ascent; last 10 m, and surfacing. The acute risks of diving (i.e., pulmonary barotrauma, nitrogen narcosis, and decompression sickness) and the potential long-term medical consequences to breath-hold diving are summarized, and an emphasis on future areas of research of this unique field of physiological adaptation are provided.
Collapse
Affiliation(s)
- Alexander Patrician
- Center for Heart, Lung & Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
| | - Željko Dujić
- Department of Integrative Physiology, University of Split School of Medicine, Split, Croatia
| | - Boris Spajić
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Ivan Drviš
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | - Philip N Ainslie
- Center for Heart, Lung & Vascular Health, University of British Columbia Okanagan, Kelowna, BC, Canada
| |
Collapse
|