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Hensel O. Cold stimulation of the oral cavity redistributes blood towards the brain in healthy volunteers. Eur J Neurol 2024; 31:e16227. [PMID: 38308448 DOI: 10.1111/ene.16227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Revised: 12/21/2023] [Accepted: 01/16/2024] [Indexed: 02/04/2024]
Abstract
BACKGROUND The aim of this study was to analyze cold stimulation-induced changes in cerebral and cardiac hemodynamics. METHODS Upon ingestion of an ice cube, the changes in resistance index, mean flow velocity and flow index of the middle cerebral arteries (MCA) were assessed using transcranial Doppler sonography. Extracranial duplex sonography was used to measure the mean flow velocity and resistance index of the right internal carotid artery (ICA). The change in mean arterial pressure, heart rate, root mean square of successive differences (RMSSD) and end-tidal carbon dioxide pressure were analyzed additionally. These changes were compared to sham stimulation. RESULTS Compared with sham stimulation, cooling of the oral cavity resulted in significant changes in cerebral and cardiac hemodynamics. The cold stimulation decreased the resistance index in the MCA (-4.5% ± 5.4%, p < 0.0001) and right ICA (-6.3% ± 15.6%, p = 0.001). This was accompanied by an increase in mean flow velocity (4.1% ± 8.0%, p < 0.0001) and flow index (10.1% ± 43.6%, p = 0.008) in the MCA. The cardiac effects caused an increase in mean arterial pressure (1.8% ± 11.2%, p = 0.017) and RMSSD (55% ± 112%, p = 0.048), while simultaneously decreasing the heart rate (-4.3% ± 9.6%, p = 0.0001). CONCLUSION Cooling of the oral cavity resulted in substantial changes in cerebral and cardiac hemodynamics resulting in a blood flow diversion to the brain.
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Affiliation(s)
- Ole Hensel
- Department of Neurology, Martin Luther University Halle-Wittenberg, Halle, Germany
- Department of Radiology, Martin Luther University Halle-Wittenberg, Halle, Germany
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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.
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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
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3
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Vrdoljak D, Foretić N, Drviš I, Ivančev V, Perić M, Dujić Ž. Do freedivers and spearfishermen differ in local muscle oxygen saturation and anaerobic power? J Sports Med Phys Fitness 2024; 64:21-29. [PMID: 37902796 DOI: 10.23736/s0022-4707.23.15185-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2023]
Abstract
BACKGROUND Freediving is defined as an activity where athletes repetitively dive and are exposed to long efforts with limited oxygen consumption. Therefore, anaerobic features are expected to be an important facet of diving performance. This study aimed to investigate differences in anaerobic capacity and local muscle oxygenation in spearfisherman and freedivers. METHODS The sample of participants included 17 male athletes (nine freedivers, and eight spearfishermen), with an average age of 37.0±8.8 years, training experience of 10.6±9.5 years, body mass of 82.5±9.5 kg and height of 184.2±5.7 cm. Anthropometric characteristics included: body mass, body height, seated height, and body fat percentage. Wingate anaerobic test was conducted, during which local muscle oxygenation was measured with a NIRS device (Moxy monitor). Wingate power outputs were measured (peak power [W/kg] and average power [W/kg]), together with muscle oxygenation variables (baseline oxygen saturation [%], desaturation slope [%/s], minimum oxygen saturation [%], half time recovery [s], and maximum oxygen saturation [%]). RESULTS The differences were not obtained between freedivers and spearfisherman in power outputs (peak power (9.24±2.08 spearfisherman; 10.68±1.04 freedivers; P=0.14); average power (6.85±0.95 spearfisherman; 7.44±0.60 freedivers; P=0.15) and muscle oxygenation parameters. However, analysis of effect size showed a moderate effect in training experience (0.71), PP (0.89), AP (0.75), Desat slope mVLR (0.66), half time recovery mVLR (0.90). CONCLUSIONS The non-existence of differences between freedivers and spearfishermen indicates similar training adaptations to the anaerobic demands. However, the results show relatively low anaerobic capacities of our divers that could serve as an incentive for the further development of these mechanisms.
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Affiliation(s)
- Dario Vrdoljak
- Faculty of Kinesiology, University of Split, Split, Croatia -
| | - Nikola Foretić
- Faculty of Kinesiology, University of Split, Split, Croatia
- High Performance Sport Center, Croatian Olympic Committee, Zagreb, Croatia
| | - Ivan Drviš
- Faculty of Kinesiology, University of Zagreb, Zagreb, Croatia
| | | | - Mia Perić
- Faculty of Kinesiology, University of Split, Split, Croatia
| | - Željko Dujić
- School of Medicine, University of Split, Split, Croatia
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Profile of precipitating factors and its implication in 160 Indian patients with Moyamoya angiopathy. J Neurol 2023; 270:1654-1661. [PMID: 36477636 PMCID: PMC9734856 DOI: 10.1007/s00415-022-11499-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2022] [Revised: 11/20/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022]
Abstract
INTRODUCTION Moyamoya angiopathy (MMA) has been known to manifest with myriad of neurological manifestations, often in association with various precipitating factors. This is the first study to systematically analyze the precipitating triggers to neurological symptoms done on the largest cohort of MMA in India. METHODS A single-centered, cross-sectional observational study, recruiting 160 patients with consecutive angiographically proven MMA over a period of 5 years (2016-2021), was undertaken to evaluate the profile of immediate precipitating factors in temporal association to the neurological symptoms, along with their clinical and radiological characteristics. SPSS 25 was used for statistical analysis. RESULTS Among the 160 patients (Adult-85, children-75), precipitating factors were seen in 41.3%, significantly higher in children (52%) than adults (31.8%) (p value: 0.011). The commonest triggers included fever (18.8%), emotional stress (8.1%), heavy exercise and diarrhea (6.3% each). Cold bath triggered MMA symptoms in 1.3%. Fever (p value: 0.008) and persistent crying (p value: 0.010) triggered neurological symptoms more commonly in children than in adults. Amongst MMA patients with precipitating factors, the commonest MMA presentation included cerebral infarction type (37.9%) and TIA (31.8%). The majority of precipitating factors that preceded an ischemic event were BP-lowing ones (54.7%). CONCLUSION Neurological symptoms of MMA are commonly associated with several precipitating factors, including the lesser known triggers like cold bath. The frequency and profile precipitating factors varies with the age of presentation and type of MMA. It can serve as an early clue to the diagnosis of MMA and its careful avoidance can be largely beneficial in limiting the distressing transient neurological symptoms.
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Breath-Hold Diving-Related Decompression Sickness with Brain Involvement: From Neuroimaging to Pathophysiology. Tomography 2022; 8:1172-1183. [PMID: 35645382 PMCID: PMC9149941 DOI: 10.3390/tomography8030096] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 04/14/2022] [Accepted: 04/15/2022] [Indexed: 11/16/2022] Open
Abstract
Central nervous system involvement related to decompression sickness (DCS) is a very rare complication of breath-hold diving. So far, it has been postulated that repeated dives with short surface intervals represent a key factor in the development of breath-holding-related DCS. We report the case of a breath-hold diver who, after repeated immersion, developed DCS with brain involvement. After treatment in a hyperbaric chamber, there was a clinical improvement in the symptoms. Magnetic resonance imaging of the brain showed hyperintense lesions in long-time repetition sequences (FLAIR, T2WI) in the left frontal and right temporal lobes. Diffusion-weighted imaging (DWI) sequences and the apparent diffusion coefficient (ADC) map were characteristic of vasogenic edema, allowing us to exclude the ischemic nature of the process. These findings, together with the acute clinical presentation, the resolution of lesions in evolutionary radiological controls and the possible involvement of blood–brain barrier/endothelial dysfunction in DCS, could suggest a new form of posterior reversible encephalopathy syndrome (PRES)-like presentation of DCS. This would represent a novel mechanism to explain the pathophysiology of this entity. We conducted a literature review, analyzing the pathophysiological and neuroimaging characteristics of DCS in breath-hold diving based on a case of this rare disease.
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Bjertnæs LJ, Næsheim TO, Reierth E, Suborov EV, Kirov MY, Lebedinskii KM, Tveita T. Physiological Changes in Subjects Exposed to Accidental Hypothermia: An Update. Front Med (Lausanne) 2022; 9:824395. [PMID: 35280892 PMCID: PMC8904885 DOI: 10.3389/fmed.2022.824395] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Accepted: 01/28/2022] [Indexed: 12/01/2022] Open
Abstract
Background Accidental hypothermia (AH) is an unintended decrease in body core temperature (BCT) to below 35°C. We present an update on physiological/pathophysiological changes associated with AH and rewarming from hypothermic cardiac arrest (HCA). Temperature Regulation and Metabolism Triggered by falling skin temperature, Thyrotropin-Releasing Hormone (TRH) from hypothalamus induces release of Thyroid-Stimulating Hormone (TSH) and Prolactin from pituitary gland anterior lobe that stimulate thyroid generation of triiodothyronine and thyroxine (T4). The latter act together with noradrenaline to induce heat production by binding to adrenergic β3-receptors in fat cells. Exposed to cold, noradrenaline prompts degradation of triglycerides from brown adipose tissue (BAT) into free fatty acids that uncouple metabolism to heat production, rather than generating adenosine triphosphate. If BAT is lacking, AH occurs more readily. Cardiac Output Assuming a 7% drop in metabolism per °C, a BCT decrease of 10°C can reduce metabolism by 70% paralleled by a corresponding decline in CO. Consequently, it is possible to maintain adequate oxygen delivery provided correctly performed cardiopulmonary resuscitation (CPR), which might result in approximately 30% of CO generated at normal BCT. Liver and Coagulation AH promotes coagulation disturbances following trauma and acidosis by reducing coagulation and platelet functions. Mean prothrombin and partial thromboplastin times might increase by 40–60% in moderate hypothermia. Rewarming might release tissue factor from damaged tissues, that triggers disseminated intravascular coagulation. Hypothermia might inhibit platelet aggregation and coagulation. Kidneys Renal blood flow decreases due to vasoconstriction of afferent arterioles, electrolyte and fluid disturbances and increasing blood viscosity. Severely deranged renal function occurs particularly in the presence of rhabdomyolysis induced by severe AH combined with trauma. Conclusion Metabolism drops 7% per °C fall in BCT, reducing CO correspondingly. Therefore, it is possible to maintain adequate oxygen delivery after 10°C drop in BCT provided correctly performed CPR. Hypothermia may facilitate rhabdomyolysis in traumatized patients. Victims suspected of HCA should be rewarmed before being pronounced dead. Rewarming avalanche victims of HCA with serum potassium > 12 mmol/L and a burial time >30 min with no air pocket, most probably be futile.
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Affiliation(s)
- Lars J Bjertnæs
- Department of Clinical Medicine, Faculty of Health Sciences, Anesthesia and Critical Care Research Group, University of Tromsø, UiT The Arctic University of Norway, Tromsø, Norway.,Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø, Norway
| | - Torvind O Næsheim
- Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø, Norway.,Department of Clinical Medicine, Faculty of Health Sciences, Cardiovascular Research Group, University of Tromsø, UiT The Arctic University of Norway, Tromsø, Norway
| | - Eirik Reierth
- Science and Health Library, University of Tromsø, UiT The Arctic University of Norway, Tromsø, Norway
| | - Evgeny V Suborov
- The Nikiforov Russian Center of Emergency and Radiation Medicine, St. Petersburg, Russia
| | - Mikhail Y Kirov
- Department of Anesthesiology and Intensive Care, Northern State Medical University, Arkhangelsk, Russia
| | - Konstantin M Lebedinskii
- Department of Anesthesiology and Intensive Care, North-Western State Medical University named after I.I. Mechnikov, St. Petersburg, Russia.,Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, Moscow, Russia
| | - Torkjel Tveita
- Department of Clinical Medicine, Faculty of Health Sciences, Anesthesia and Critical Care Research Group, University of Tromsø, UiT The Arctic University of Norway, Tromsø, Norway.,Division of Surgical Medicine and Intensive Care, University Hospital of North Norway, Tromsø, Norway
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Miller GD, Maxwell JD, Thompson A, Cable NT, Low DA, George KP, Jones H. The effects of exercise training in the cold on cerebral blood flow and cerebrovascular function in young healthy individuals. Auton Neurosci 2022; 238:102945. [PMID: 35176639 DOI: 10.1016/j.autneu.2022.102945] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Revised: 11/09/2021] [Accepted: 01/16/2022] [Indexed: 11/17/2022]
Abstract
Exercise elicits acute increases in cerebral blood flow velocity (CBFv) and provokes long-term beneficial effects on CBFv, thereby reducing cerebrovascular risk. Acute exposure to a cold stimulus also increases CBFv. We compared the impact of exercise training in cold and thermoneutral environments on CFBv, cerebrovascular function and peripheral endothelial function. Twenty-one (16 males, 22 ± 5 years) individuals were randomly allocated to either a cold (5 °C) or thermoneutral (15 °C) exercise intervention. Exercise consisted of 50-min cycling at 70% heart rate max, three times per week for eight weeks. Transcranial Doppler was used to determine pre and post intervention CBFv, dynamic cerebral autoregulation (dCA) and cerebrovascular reactivity (CVRCO2). Conduit endothelial function, microvascular function and cardiorespiratory fitness were also assessed. Cardiorespiratory fitness improved (2.91 ml.min.kg-1, 95%CI 0.49, 5.3; P = 0.02), regardless of exercise setting. Neither intervention had an impact on CBFv, CVRCO2, FMD or microvascular function (P > 0.05). There was a significant interaction between time and condition for dCA normalised gain with evidence of a decrease by 0.192%cm.s-1.%mmHg-1 (95%CI -0.318, -0.065) following training in the cold and increase (0.129%cm.s-1.%mmHg-1, 95%CI 0.011, 0.248) following training in the thermoneutral environment (P = 0.001). This was also evident for dCA phase with evidence of an increase by 0.072 rad (95%CI -0.007, 0.152) following training in the cold and decrease by 0.065 (95%CI -0.144, 0.014) radians following training in the thermoneutral environment (P = 0.02). Both training interventions improved fitness but CBFv, CVRCO2 and peripheral endothelial function were unaltered. Exercise training in the cold improved dCA whereas thermoneutral negated dCA.
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Affiliation(s)
- G D Miller
- Research Institute of Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - J D Maxwell
- Manchester University NHS Foundation Trust, Manchester, UK
| | - A Thompson
- Wolfson Centre for Personalised Medicine, Institute of Translational Medicine, University of Liverpool, Liverpool, UK
| | - N T Cable
- The Institute of Sport, Manchester Metropolitan University, Manchester, UK
| | - D A Low
- Research Institute of Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - K P George
- Research Institute of Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK
| | - H Jones
- Research Institute of Sport and Exercise Science, Liverpool John Moores University, Liverpool, UK.
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Veiga S, Pla R, Qiu X, Boudet D, Guimard A. Effects of Extended Underwater Sections on the Physiological and Biomechanical Parameters of Competitive Swimmers. Front Physiol 2022; 13:815766. [PMID: 35177993 PMCID: PMC8845443 DOI: 10.3389/fphys.2022.815766] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2021] [Accepted: 01/10/2022] [Indexed: 12/05/2022] Open
Abstract
Despite changes in the underwater sections of swimming races affecting overall performance, there is no information about the effects of the apnea-induced changes on the physiological state of competitive swimmers. The aim of the present research was to examine the effect of changes in the underwater race sections on the physiological [blood lactate concentration, heart rate, and rating of perceived exertion (RPE)] and biomechanical (underwater time, distance, and velocity) parameters of competitive swimmers. Twelve youth competitive swimmers belonging to the national team (706 ± 28.9 FINA points) performed 2 × 75 m efforts under three different conditions, while maintaining a 200 m race pace: (1) free underwater sections, (2) kick number of condition 1 plus two kicks, and (3) maximum distance underwater. Overall performance was maintained, and underwater section durations increased from condition 1 to 3 as expected according to the experimental design. Heart rate and blood lactate concentration values did not show differences between conditions, but the RPE values were significantly greater (F2, 36 = 18.00, p = 0.001, η2: 0.50) for the constrained (conditions 2 and 3) vs. the free underwater condition. Underwater parameters were modified within the 75 m efforts (lap 1 to lap 3), but the magnitude of changes did not depend on the experimental condition (all lap × condition effects p > 0.05). Controlled increases of underwater sections in trained swimmers can led to optimizing performance in these race segments despite small increases of perceived discomfort.
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Affiliation(s)
- Santiago Veiga
- Departamento de Deportes, Facultad de Ciencias de la Actividad Física y del Deporte—INEF, Universidad Politécnica de Madrid, Madrid, Spain
| | - Robin Pla
- French Swimming Federation, Clichy, France
- Institut de Recherche BioMédicale et d’Epidémiologie du Sport, IRMES, Paris, France
| | - Xiao Qiu
- Departamento de Deportes, Facultad de Ciencias de la Actividad Física y del Deporte—INEF, Universidad Politécnica de Madrid, Madrid, Spain
- Institute of Sports and Sport Science, University of Kassel, Kassel, Germany
| | | | - Alexandre Guimard
- Université Sorbonne Paris Nord, Hypoxie et Poumon, H&P, INSERM, UMR 1272, Bobigny, France
- Département STAPS, Université Sorbonne Paris Nord, Bobigny, France
- *Correspondence: Alexandre Guimard,
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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.
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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
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Bjertnaes LJ, Hauge A, Thoresen M, Walløe L. Prioritized Brain Circulation During Ergometer Cycling with Apnea and Face Immersion in Ice-Cold Water: A Case Report. Int Med Case Rep J 2021; 14:675-681. [PMID: 34602825 PMCID: PMC8478670 DOI: 10.2147/imcrj.s317404] [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: 04/25/2021] [Accepted: 08/26/2021] [Indexed: 11/23/2022] Open
Abstract
Background Successful cardiopulmonary resuscitation after drowning or avalanche is often attributed to hypothermia-induced decrease in metabolism, which adapts the oxygen demand to the amount supplied under cardiac compression. Four decades ago, we speculated if oxygen-sparing mechanisms like those found in marine mammals, may improve cerebral oxygenation during acute airway blockade in humans. We investigated hemodynamic changes during steady state ergometer cycling with intermittent periods of apnea and face immersion (AFI) in ice-cold water. During AFI, heart rate (HR) dropped by 58% whereas average blood velocity (ABV) determined by means of a Doppler ultrasound velocity meter (UNIDOP University of Oslo, Oslo, Norway) fell by 85% in the radial artery and rose by 67% in the vertebral artery. Similar changes occured in radial artery ABV, albeit more slowly, when the test subject only held his breath while cycling. When he breathed via a snorkel during face immersion, HR remained unchanged while radial artery ABV fell transiently and subsequently returned to its pre-immersion level. These findings later were confirmed by other investigators. Moreover, a recent study revealed that the seal even has a system for selective brain cooling during the dive. Conclusion Our research has confirmed prioritized cerebral circulation during AFI in cold water. We hypothesize that these changes may improve brain oxygenation due both to greater blood flow and possibly also to faster brain cooling, as demonstrated in diving seals.
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Affiliation(s)
- Lars J Bjertnaes
- Anesthesia and Critical Care Research Group, Department of Clinical Medicine, Faculty of Health Sciences, UiT The Arctic University of Norway, Tromsø, N-9037, Norway.,Department of Intensive Care Medicine, University Hospital of North Norway, Tromsø, N- 9017, Norway
| | - Anton Hauge
- Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, 0317, Norway
| | - Marianne Thoresen
- Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, 0317, Norway.,Translational Health Sciences, University of Bristol, Bristol, UK
| | - Lars Walløe
- Division of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, 0317, Norway
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Riera F, Monjo R, Coudevylle GR, Meric H, Hue O. Face Cooling During Swimming Training in Tropical Condition. Front Psychol 2021; 12:622184. [PMID: 33967888 PMCID: PMC8102736 DOI: 10.3389/fpsyg.2021.622184] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 03/25/2021] [Indexed: 12/04/2022] Open
Abstract
The aim of this study was to test the effect of face cooling with cold water (1.2 ± 0.7°C) vs. face cooling with neutral water (28.0 ± 3.0°C) during high-intensity swimming training on both the core temperature (Tco) and thermal perceptions in internationally ranked long-distance swimmers (5 men’s and 3 women’s) during 2 randomized swimming sessions. After a standardized warm-up of 1,200 m, the athletes performed a standardized training session that consisted of 2,000 m (5 × 400 m; start every 5’15”) at a best velocity then 600 m of aerobic work. Heart rate (HR) was continuously monitored during 5 × 400 m, whereas Tco, thermal comfort (TC), and thermal sensation (TS) were measured before and after each 400 m. Before and after each 400 m, the swimmers were asked to flow 200 mL of cold water (1.2°C) or neutral (22°C) water packaged in standardized bottles on their face. The swimmers were asked don’t drink during exercise. The velocity was significantly different between cold water and neutral water (p < 0.004 – 71.58 m.min–1 ± 2.32 and 70.52 m.min–1 ± 1.73, respectively). The Tco was increased by ±0.5°C at race pace, under both face cooling conditions with no significant difference. No significant changes were noted in mean HR (i.e., 115 ± 9 and 114 ± 15 bpm for NW and CW, respectively). TC was higher with Cold Cooling than Neutral Cooling and TS was lower with Cold cooling compared with Neutral cooling. The changes in perceptual parameters caused by face cooling with cold water reflect the psychological impact on the physical parameters. The mean velocity was less important with face cooling whereas the heat rate and Tco were the same in the both conditions. The mechanism leading to these results seems to involve brain integration of signals from physiological and psychological sources.
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Affiliation(s)
- Florence Riera
- Laboratory ACTES, UPRES-EA 3596, University of the French West Indies, Point-à-Pitre, France.,Laboratory IMAGE, UMR ESPACE DEV 228, University of Perpignan Via Domitia, Perpignan, France
| | - Roland Monjo
- Laboratory ACTES, UPRES-EA 3596, University of the French West Indies, Point-à-Pitre, France
| | - Guillaume R Coudevylle
- Laboratory ACTES, UPRES-EA 3596, University of the French West Indies, Point-à-Pitre, France
| | - Henri Meric
- Laboratory IMAGE, UMR ESPACE DEV 228, University of Perpignan Via Domitia, Perpignan, France
| | - Olivier Hue
- Laboratory ACTES, UPRES-EA 3596, University of the French West Indies, Point-à-Pitre, France
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12
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Physiology, pathophysiology and (mal)adaptations to chronic apnoeic training: a state-of-the-art review. Eur J Appl Physiol 2021; 121:1543-1566. [PMID: 33791844 PMCID: PMC8144079 DOI: 10.1007/s00421-021-04664-x] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/04/2021] [Indexed: 02/08/2023]
Abstract
Breath-hold diving is an activity that humans have engaged in since antiquity to forage for resources, provide sustenance and to support military campaigns. In modern times, breath-hold diving continues to gain popularity and recognition as both a competitive and recreational sport. The continued progression of world records is somewhat remarkable, particularly given the extreme hypoxaemic and hypercapnic conditions, and hydrostatic pressures these athletes endure. However, there is abundant literature to suggest a large inter-individual variation in the apnoeic capabilities that is thus far not fully understood. In this review, we explore developments in apnoea physiology and delineate the traits and mechanisms that potentially underpin this variation. In addition, we sought to highlight the physiological (mal)adaptations associated with consistent breath-hold training. Breath-hold divers (BHDs) are evidenced to exhibit a more pronounced diving-response than non-divers, while elite BHDs (EBHDs) also display beneficial adaptations in both blood and skeletal muscle. Importantly, these physiological characteristics are documented to be primarily influenced by training-induced stimuli. BHDs are exposed to unique physiological and environmental stressors, and as such possess an ability to withstand acute cerebrovascular and neuronal strains. Whether these characteristics are also a result of training-induced adaptations or genetic predisposition is less certain. Although the long-term effects of regular breath-hold diving activity are yet to be holistically established, preliminary evidence has posed considerations for cognitive, neurological, renal and bone health in BHDs. These areas should be explored further in longitudinal studies to more confidently ascertain the long-term health implications of extreme breath-holding activity.
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13
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Cardiac hypoxic resistance and decreasing lactate during maximum apnea in elite breath hold divers. Sci Rep 2021; 11:2545. [PMID: 33510292 PMCID: PMC7844051 DOI: 10.1038/s41598-021-81797-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2019] [Accepted: 01/06/2021] [Indexed: 01/30/2023] Open
Abstract
Breath-hold divers (BHD) enduring apnea for more than 4 min are characterized by resistance to release of reactive oxygen species, reduced sensitivity to hypoxia, and low mitochondrial oxygen consumption in their skeletal muscles similar to northern elephant seals. The muscles and myocardium of harbor seals also exhibit metabolic adaptations including increased cardiac lactate-dehydrogenase-activity, exceeding their hypoxic limit. We hypothesized that the myocardium of BHD possesses similar adaptive mechanisms. During maximum apnea 15O-H2O-PET/CT (n = 6) revealed no myocardial perfusion deficits but increased myocardial blood flow (MBF). Cardiac MRI determined blood oxygen level dependence oxygenation (n = 8) after 4 min of apnea was unaltered compared to rest, whereas cine-MRI demonstrated increased left ventricular wall thickness (LVWT). Arterial blood gases were collected after warm-up and maximum apnea in a pool. At the end of the maximum pool apnea (5 min), arterial saturation decreased to 52%, and lactate decreased 20%. Our findings contrast with previous MR studies of BHD, that reported elevated cardiac troponins and decreased myocardial perfusion after 4 min of apnea. In conclusion, we demonstrated for the first time with 15O-H2O-PET/CT and MRI in elite BHD during maximum apnea, that MBF and LVWT increases while lactate decreases, indicating anaerobic/fat-based cardiac-metabolism similar to diving mammals.
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14
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Panneton WM, Gan Q. The Mammalian Diving Response: Inroads to Its Neural Control. Front Neurosci 2020; 14:524. [PMID: 32581683 PMCID: PMC7290049 DOI: 10.3389/fnins.2020.00524] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 04/27/2020] [Indexed: 01/03/2023] Open
Abstract
The mammalian diving response (DR) is a remarkable behavior that was first formally studied by Laurence Irving and Per Scholander in the late 1930s. The DR is called such because it is most prominent in marine mammals such as seals, whales, and dolphins, but nevertheless is found in all mammals studied. It consists generally of breathing cessation (apnea), a dramatic slowing of heart rate (bradycardia), and an increase in peripheral vasoconstriction. The DR is thought to conserve vital oxygen stores and thus maintain life by directing perfusion to the two organs most essential for life-the heart and the brain. The DR is important, not only for its dramatic power over autonomic function, but also because it alters normal homeostatic reflexes such as the baroreceptor reflex and respiratory chemoreceptor reflex. The neurons driving the reflex circuits for the DR are contained within the medulla and spinal cord since the response remains after the brainstem transection at the pontomedullary junction. Neuroanatomical and physiological data suggesting brainstem areas important for the apnea, bradycardia, and peripheral vasoconstriction induced by underwater submersion are reviewed. Defining the brainstem circuit for the DR may open broad avenues for understanding the mechanisms of suprabulbar control of autonomic function in general, as well as implicate its role in some clinical states. Knowledge of the proposed diving circuit should facilitate studies on elite human divers performing breath-holding dives as well as investigations on sudden infant death syndrome (SIDS), stroke, migraine headache, and arrhythmias. We have speculated that the DR is the most powerful autonomic reflex known.
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Affiliation(s)
- W. Michael Panneton
- Department of Pharmacological and Physiological Science, School of Medicine, Saint Louis University, St. Louis, MO, United States
| | - Qi Gan
- Department of Pharmacological and Physiological Science, School of Medicine, Saint Louis University, St. Louis, MO, United States
- Department of Pediatrics, School of Medicine, Saint Louis University, St. Louis, MO, United States
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15
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AlSalahi SE, Braz ID, Ahmed A, Junejo RT, Fisher JP. Human cerebrovascular responses to diving are not related to facial cooling. Exp Physiol 2020; 105:940-949. [PMID: 32162738 DOI: 10.1113/ep087529] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/24/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Does facial cooling-mediated stimulation of cutaneous trigeminal afferents associated with the diving response increase cerebral blood flow or are factors associated with breath-holding (e.g. arterial carbon dioxide accumulation, pressor response) more important in humans? What is the main finding and its importance? Physiological factors associated with breath-holding such as arterial carbon dioxide accumulation and the pressor response, but not facial cooling (trigeminal nerve stimulation), make the predominant contribution to diving response-mediated increases in cerebral blood flow in humans. ABSTRACT Diving evokes a pattern of physiological responses purported to preserve oxygenated blood delivery to vital organs such as the brain. We sought to uncouple the effects of trigeminal nerve stimulation on cerebral blood flow (CBF) from other modifiers associated with the diving response, such as apnoea and changes in arterial carbon dioxide tension. Thirty-seven young healthy individuals participated in separate trials of facial cooling (FC, 3 min) and cold pressor test (CPT, 3 min) under poikilocapnic (Protocol 1) and isocapnic conditions (Protocol 2), facial cooling while either performing a breath-hold (FC +BH) or breathing spontaneously for a matched duration (FC -BH) (Protocol 3), and BH during facial cooling (BH +FC) or without facial cooling (BH -FC) (Protocol 4). Under poikilocapnic conditions neither facial cooling nor CPT evoked a change in middle cerebral artery blood flow velocity (MCA vmean ; transcranial Doppler) (P > 0.05 vs. baseline). Under isocapnic conditions, facial cooling did not change MCA vmean (P > 0.05), whereas CPT increased MCA vmean by 13% (P < 0.05). Facial cooling with a concurrent BH markedly increased MCA vmean (Δ23%) and internal carotid artery blood flow (ICAQ ; duplex Doppler ultrasound) (Δ26%) (P < 0.001), but no change in MCA vmean and ICAQ was observed when facial cooling was accompanied by spontaneous breathing (P > 0.05). Finally, MCA vmean and ICAQ were similarly increased by BH either with or without facial cooling. These findings suggest that physiological factors associated with BH, and not facial cooling (i.e. trigeminal nerve stimulation) per se, make the predominant contribution to increases in CBF during diving in humans.
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Affiliation(s)
- Sultan E AlSalahi
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Igor D Braz
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK.,University Center of Volta Redonda, Volta Redonda, Rio de Janeiro, Brazil
| | - Amar Ahmed
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - Rehan T Junejo
- School of Sport, Exercise and Rehabilitation Sciences, College of Life and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham, UK
| | - James P Fisher
- Department of Physiology, Faculty of Medical & Health Sciences, University of Auckland, Auckland, New Zealand
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16
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Windsor JS, Newman J, Sheppard M. Cardiovascular Disease and Triathlon-Related Deaths in the United Kingdom. Wilderness Environ Med 2020; 31:31-37. [PMID: 32057629 DOI: 10.1016/j.wem.2019.11.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2018] [Revised: 10/24/2019] [Accepted: 11/04/2019] [Indexed: 12/17/2022]
Abstract
INTRODUCTION Triathlon is one of the fastest growing sports in the United Kingdom. However, in recent years several deaths have occurred. The intention of this study is to identify these cases and examine the role cardiovascular disease played in these deaths. METHODS An extensive online search was performed to identify triathlon-related deaths (TRDs) in the United Kingdom and UK citizens who died during or as a result of competing in triathlons abroad. British Triathlon provided the number of participants who took part in UK-based events. Coroners provided information on all those who died. RESULTS Between 2009 and 2015, 991,186 participants took part in British Triathlon-sanctioned events. Five TRDs in the United Kingdom were identified. The mortality rate was 0.5 per 100,000 participants. Deaths occurred during or after the swim (3), cycle (1), and run (1) events. During the same period, 5 TRDs were identified among UK citizens competing abroad. These deaths occurred during or after the swim (2), cycle (1), and run (2) events. Cardiovascular pathology was cited as a cause or contributing factor in half of the fatalities. Four deaths were referred to a specialist cardiac pathology service for autopsy. CONCLUSIONS Cardiovascular disease was found to be the most common cause of TRD. Further research is needed to determine the underlying cardiac pathology that triggers TRDs. With this information it may be possible to develop screening tools that can prevent similar fatalities from occurring in the future.
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Affiliation(s)
| | | | - Mary Sheppard
- Molecular and Clinical Sciences Research Institute, St George's, University of London, London, United Kingdom
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17
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Vincenzi FF. Sudden Unexpected Death and the Mammalian Dive Response: Catastrophic Failure of a Complex Tightly Coupled System. Front Physiol 2019; 10:97. [PMID: 30886584 PMCID: PMC6389676 DOI: 10.3389/fphys.2019.00097] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Accepted: 01/25/2019] [Indexed: 01/02/2023] Open
Abstract
In tightly coupled complex systems, when two or more factors or events interact in unanticipated ways, catastrophic failures of high-risk technical systems happen rarely, but quickly. Safety features are commonly built into complex systems to avoid disasters but are often part of the problem. The human body may be considered as a complex tightly coupled system at risk of rare catastrophic failure (sudden unexpected death, SUD) when certain factors or events interact. The mammalian dive response (MDR) is a built-in safety feature of the body that normally conserves oxygen during acute hypoxia. Activation of the MDR is the final pathway to sudden cardiac (SCD) in some cases of sudden infant death syndrome (SIDS), sudden unexpected death in epilepsy (SUDEP), and sudden cardiac death in water (SCDIW, fatal drowning). There is no single cause in any of these death scenarios, but an array of, unanticipated, often unknown, factors or events that activate or interact with the mammalian dive reflex. In any particular case, the relevant risk factors or events might include a combination of genetic, developmental, metabolic, disease, environmental, or operational influences. Determination of a single cause in any of these death scenarios is unlikely. The common thread among these seemingly different death scenarios is activation of the mammalian dive response. The human body is a complex tightly coupled system at risk of rare catastrophic failure when that "safety feature" is activated.
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Affiliation(s)
- Frank F. Vincenzi
- Department of Pharmacology, University of Washington, Seattle, WA, United States
- Pharmacological Information and Consultation Service, Arlington, WA, United States
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18
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Kjeld T, Stride N, Gudiksen A, Hansen EG, Arendrup HC, Horstmann PF, Zerahn B, Jensen LT, Nordsborg N, Bejder J, Halling JF. Oxygen conserving mitochondrial adaptations in the skeletal muscles of breath hold divers. PLoS One 2018; 13:e0201401. [PMID: 30231055 PMCID: PMC6145504 DOI: 10.1371/journal.pone.0201401] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 07/14/2018] [Indexed: 12/22/2022] Open
Abstract
Background The performance of elite breath hold divers (BHD) includes static breath hold for more than 11 minutes, swimming as far as 300 m, or going below 250 m in depth, all on a single breath of air. Diving mammals are adapted to sustain oxidative metabolism in hypoxic conditions through several metabolic adaptations, including improved capacity for oxygen transport and mitochondrial oxidative phosphorylation in skeletal muscle. It was hypothesized that similar adaptations characterized human BHD. Hence, the purpose of this study was to examine the capacity for oxidative metabolism in skeletal muscle of BHD compared to matched controls. Methods Biopsies were obtained from the lateral vastus of the femoral muscle from 8 Danish BHD and 8 non-diving controls (Judo athletes) matched for morphometry and whole body VO2max. High resolution respirometry was used to determine mitochondrial respiratory capacity and leak respiration with simultaneous measurement of mitochondrial H2O2 emission. Maximal citrate synthase (CS) and 3-hydroxyacyl CoA dehydrogenase (HAD) activity were measured in muscle tissue homogenates. Western Blotting was used to determine protein contents of respiratory complex I-V subunits and myoglobin in muscle tissue lysates. Results Muscle biopsies of BHD revealed lower mitochondrial leak respiration and electron transfer system (ETS) capacity and higher H2O2 emission during leak respiration than controls, with no differences in enzyme activities (CS and HAD) or protein content of mitochondrial complex subunits myoglobin, myosin heavy chain isoforms, markers of glucose metabolism and antioxidant enzymes. Conclusion We demonstrated for the first time in humans, that the skeletal muscles of BHD are characterized by lower mitochondrial oxygen consumption both during low leak and high (ETS) respiration than matched controls. This supports previous observations of diving mammals demonstrating a lower aerobic mitochondrial capacity of the skeletal muscles as an oxygen conserving adaptation during prolonged dives.
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Affiliation(s)
- Thomas Kjeld
- Department of Anesthesiology, Herlev Hospital, Herlev, University of Copenhagen, Denmark
- * E-mail:
| | - Nis Stride
- Department of Cardiology, Rigshospitalet, Copenhagen, University of Copenhagen, Denmark
| | - Anders Gudiksen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Egon Godthaab Hansen
- Department of Anesthesiology, Herlev Hospital, Herlev, University of Copenhagen, Denmark
| | | | | | - Bo Zerahn
- Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, Herlev, University of Copenhagen, Denmark
| | - Lars Thorbjørn Jensen
- Department of Clinical Physiology and Nuclear Medicine, Herlev Hospital, Herlev, University of Copenhagen, Denmark
| | - Nikolai Nordsborg
- Department of Nutrition, Exercise and Sport (NEXS), Copenhagen, University of Copenhagen, Denmark
| | - Jacob Bejder
- Department of Nutrition, Exercise and Sport (NEXS), Copenhagen, University of Copenhagen, Denmark
| | - Jens Frey Halling
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
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19
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Vega JL. Ictal Mammalian Dive Response: A Likely Cause of Sudden Unexpected Death in Epilepsy. Front Neurol 2018; 9:677. [PMID: 30174646 PMCID: PMC6108060 DOI: 10.3389/fneur.2018.00677] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2018] [Accepted: 07/27/2018] [Indexed: 12/22/2022] Open
Abstract
Even though sudden unexpected death in epilepsy (SUDEP) takes the lives of thousands of otherwise healthy epilepsy patients every year, the physiopathology associated with this condition remains unexplained. This article explores important parallels, which exist between the clinical observations and pathological responses associated with SUDEP, and the pathological responses that can develop when a set of autonomic reflexes known as the mammalian dive response (MDR) is deployed. Mostly unknown to physicians, this evolutionarily conserved physiological response to prolonged apnea economizes oxygen for preferential use by the brain. However, the drastic cardiovascular adjustments required for its execution, which include severe bradycardia and the sequestration of a significant portion of the total blood volume inside the cardiopulmonary vasculature, can result in many of the same pathological responses associated with SUDEP. Thus, this article advances the hypothesis that prolonged apneic generalized tonic clonic seizures induce augmented forms of the MDR, which, in the most severe cases, cause SUDEP.
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Affiliation(s)
- Jose L Vega
- Department of Neurosciences and Stroke, Novant Health, Forsyth Medical Center, Winston-Salem, NC, United States.,TeleNeurologia SAS, Medellin, Colombia
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20
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Abstract
Breath-hold diving is practiced by recreational divers, seafood divers, military divers, and competitive athletes. It involves highly integrated physiology and extreme responses. This article reviews human breath-hold diving physiology beginning with an historical overview followed by a summary of foundational research and a survey of some contemporary issues. Immersion and cardiovascular adjustments promote a blood shift into the heart and chest vasculature. Autonomic responses include diving bradycardia, peripheral vasoconstriction, and splenic contraction, which help conserve oxygen. Competitive divers use a technique of lung hyperinflation that raises initial volume and airway pressure to facilitate longer apnea times and greater depths. Gas compression at depth leads to sequential alveolar collapse. Airway pressure decreases with depth and becomes negative relative to ambient due to limited chest compliance at low lung volumes, raising the risk of pulmonary injury called "squeeze," characterized by postdive coughing, wheezing, and hemoptysis. Hypoxia and hypercapnia influence the terminal breakpoint beyond which voluntary apnea cannot be sustained. Ascent blackout due to hypoxia is a danger during long breath-holds, and has become common amongst high-level competitors who can suppress their urge to breathe. Decompression sickness due to nitrogen accumulation causing bubble formation can occur after multiple repetitive dives, or after single deep dives during depth record attempts. Humans experience responses similar to those seen in diving mammals, but to a lesser degree. The deepest sled-assisted breath-hold dive was to 214 m. Factors that might determine ultimate human depth capabilities are discussed. © 2018 American Physiological Society. Compr Physiol 8:585-630, 2018.
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21
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Ichinose M, Matsumoto M, Fujii N, Yoshitake N, Nishiyasu T. Voluntary apnea during dynamic exercise activates the muscle metaboreflex in humans. Am J Physiol Heart Circ Physiol 2017; 314:H434-H442. [PMID: 29101169 DOI: 10.1152/ajpheart.00367.2017] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Voluntary apnea during dynamic exercise evokes marked bradycardia, peripheral vasoconstriction, and pressor responses. However, the mechanism(s) underlying the cardiovascular responses seen during apnea in exercising humans is unknown. We therefore tested the hypothesis that the muscle metaboreflex contributes to the apnea-induced pressor response during dynamic exercise. Thirteen healthy subjects participated in apnea and control trials. In both trials, subjects performed a two-legged dynamic knee extension exercise at a workload that elicited heart rates at ~100 beats/min. In the apnea trial, after reaching a steady state, subjects began voluntary apnea. Immediately after cessation of the apnea, arterial occlusion was initiated at both thighs and the subjects stopped exercising. The occlusion was sustained for 3 min in the postexercise period. In the control trial, the occlusion was started without subjects performing the apnea. The apnea induced marked bradycardia, pressor responses, and decreases in arterial O2 saturation, cardiac output, and total vascular conductance. In addition, arterial blood pressure was significantly higher and total vascular conductance was significantly lower in the apnea trials than the control trials throughout the occlusion period. In separate sessions, we measured apnea-induced changes in exercising leg blood flow in the same subjects. Leg blood flow was significantly reduced by apnea and reached the resting level at the peak of the apnea response. We conclude that the muscle metaboreflex is activated by the decrease in O2 delivery to the working muscle during apnea in exercising humans and contributes to the large pressor response. NEW & NOTEWORTHY We demonstrated that apnea during dynamic exercise activates the muscle metaboreflex in humans. This result indicates that a reduction in O2 delivery to working muscle triggers the muscle metaboreflex during apnea. Activation of the muscle metaboreflex is one of the mechanisms underlying the marked apnea-induced pressor response.
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Affiliation(s)
- Masashi Ichinose
- Human Integrative Physiology Laboratory, School of Business Administration, Meiji University , Tokyo , Japan
| | - Mayumi Matsumoto
- Institute of Health and Sport Sciences, University of Tsukuba , Ibaraki , Japan
| | - Naoto Fujii
- Institute of Health and Sport Sciences, University of Tsukuba , Ibaraki , Japan
| | - Narumi Yoshitake
- Institute of Health and Sport Sciences, University of Tsukuba , Ibaraki , Japan
| | - Takeshi Nishiyasu
- Institute of Health and Sport Sciences, University of Tsukuba , Ibaraki , Japan
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22
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Mijacika T, Kyhl K, Frestad D, Otto Barak F, Drvis I, Secher NH, Dujic Z, Lav Madsen P. Effect of pulmonary hyperinflation on central blood volume: An MRI study. Respir Physiol Neurobiol 2017; 243:92-96. [PMID: 28583413 DOI: 10.1016/j.resp.2017.05.012] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 05/31/2017] [Indexed: 11/25/2022]
Abstract
Pulmonary hyperinflation attained by glossopharyngeal insufflation (GPI) challenges the circulation by compressing the heart and pulmonary vasculature. Our aim was to determine the amount of blood translocated from the central blood volume during GPI. Cardiac output and cardiac chamber volumes were assessed by magnetic resonance imaging in twelve breath-hold divers at rest and during apnea with GPI. Pulmonary blood volume was determined from pulmonary blood flow and transit times for gadolinium during first-pass perfusion after intravenous injection. During GPI, the lung volume increased by 0.8±0.6L (11±7%) above the total lung capacity. All cardiac chambers decreased in volume and despite a heart rate increase of 24±29 bpm (39±50%), pulmonary blood flow decreased by 2783±1820mL (43±20%). The pulmonary transit time remained unchanged at 7.5±2.2s and pulmonary blood volume decreased by 354±176mL (47±15%). In total, central blood volume decreased by 532±248mL (46±14%). Voluntary pulmonary hyperinflation leads to ∼50% decrease in pulmonary and central blood volume.
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Affiliation(s)
- Tanja Mijacika
- Dept. of Integrative Physiology, University of Split School of Medicine, Croatia
| | - Kasper Kyhl
- The Cardiac MRI group, Dept. Cardiology, Rigshospitalet, University of Copenhagen, Denmark
| | - Daria Frestad
- Dept. of Cardiology, Copenhagen University Hospital, Hvidovre, University of Copenhagen, Denmark
| | - F Otto Barak
- Dept. of Integrative Physiology, University of Split School of Medicine, Croatia; Dept. of Physiology, Faculty of Medicine, University of Novi Sad, Serbia
| | - Ivan Drvis
- University of Zagreb Faculty of Kinesiology, Croatia
| | - Niels H Secher
- Dept. of Anesthesiology, The Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Denmark
| | - Zeljko Dujic
- Dept. of Integrative Physiology, University of Split School of Medicine, Croatia.
| | - Per Lav Madsen
- Dept. of Cardiology, Copenhagen University Hospital, Herlev, University of Copenhagen, Denmark
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23
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Eichhorn L, Dolscheid-Pommerich R, Erdfelder F, Ayub MA, Schmitz T, Werner N, Jansen F. Sustained apnea induces endothelial activation. Clin Cardiol 2017; 40:704-709. [PMID: 28464406 DOI: 10.1002/clc.22720] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 03/28/2017] [Accepted: 03/30/2017] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Apnea diving has gained worldwide popularity, even though the pathophysiological consequences of this challenging sport on the human body are poorly investigated and understood. This study aims to assess the influence of sustained apnea in healthy volunteers on circulating microparticles (MPs) and microRNAs (miRs), which are established biomarkers reflecting vascular function. HYPOTHESIS Short intermittent hypoxia due to voluntary breath-holding affects circulating levels of endothelial cell-derived MPs (EMPs) and endothelial cell-derived miRs. METHODS Under dry laboratory conditions, 10 trained apneic divers performed maximal breath-hold. Venous blood samples were taken, once before and at 4 defined points in time after apnea. Samples were analyzed for circulating EMPs and endothelial miRs. RESULTS Average apnea time was 329 seconds (±103), and SpO2 at the end of apnea was 79% (±12). Apnea was associated with a time-dependent increase of circulating endothelial cell-derived EMPs and endothelial miRs. Levels of circulating EMPs in the bloodstream reached a peak 4 hours after the apnea period and returned to baseline levels after 24 hours. Circulating miR-126 levels were elevated at all time points after a single voluntary maximal apnea, whereas miR-26 levels were elevated significantly only after 30 minutes and 4 hours. Also miR-21 and miR-92 levels increased, but did not reach the level of significance. CONCLUSIONS Even a single maximal breath-hold induces acute endothelial activation and should be performed with great caution by subjects with preexisting vascular diseases. Voluntary apnea might be used as a model to simulate changes in endothelial function caused by hypoxia in humans.
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Affiliation(s)
- Lars Eichhorn
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Bonn, Bonn, Germany
| | | | - Felix Erdfelder
- Department of Anesthesiology and Intensive Care Medicine, University Hospital of Bonn, Bonn, Germany
| | | | - Theresa Schmitz
- Department of Medicine II, Heart Center Bonn, University Hospital of Bonn, Bonn, Germany
| | - Nikos Werner
- Department of Medicine II, Heart Center Bonn, University Hospital of Bonn, Bonn, Germany
| | - Felix Jansen
- Department of Medicine II, Heart Center Bonn, University Hospital of Bonn, Bonn, Germany
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Bierens JJLM, Lunetta P, Tipton M, Warner DS. Physiology Of Drowning: A Review. Physiology (Bethesda) 2017; 31:147-66. [PMID: 26889019 DOI: 10.1152/physiol.00002.2015] [Citation(s) in RCA: 53] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Drowning physiology relates to two different events: immersion (upper airway above water) and submersion (upper airway under water). Immersion involves integrated cardiorespiratory responses to skin and deep body temperature, including cold shock, physical incapacitation, and hypovolemia, as precursors of collapse and submersion. The physiology of submersion includes fear of drowning, diving response, autonomic conflict, upper airway reflexes, water aspiration and swallowing, emesis, and electrolyte disorders. Submersion outcome is determined by cardiac, pulmonary, and neurological injury. Knowledge of drowning physiology is scarce. Better understanding may identify methods to improve survival, particularly related to hot-water immersion, cold shock, cold-induced physical incapacitation, and fear of drowning.
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Affiliation(s)
| | - Philippe Lunetta
- Department of Pathology and Forensic Medicine, University of Turku, Turku, Finland
| | - Mike Tipton
- Department of Sport and Exercise Science, Extreme Environments Laboratory, University of Portsmouth, Portsmouth, United Kingdom; and
| | - David S Warner
- Departments of Anesthesiology, Neurobiology and Surgery, Duke University Medical Center, Durham, North Carolina
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Mijacika T, Frestad D, Kyhl K, Barak O, Drvis I, Secher NH, Buca A, Obad A, Dujic Z, Madsen PL. Blood pooling in extrathoracic veins after glossopharyngeal insufflation. Eur J Appl Physiol 2017; 117:641-649. [PMID: 28243777 DOI: 10.1007/s00421-017-3545-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2016] [Accepted: 01/10/2017] [Indexed: 10/20/2022]
Abstract
PURPOSE Trained breath-hold divers hyperinflate their lungs by glossopharyngeal insufflation (GPI) to prolong submersion time and withstand lung collapse at depths. Pulmonary hyperinflation leads to profound hemodynamic changes. METHODS Thirteen divers performed preparatory breath-holds followed by apnea with GPI. Filling of extrathoracic veins was determined by ultrasound and magnetic resonance imaging and peripheral extravasation of fluid was assessed by electrical impedance. Femoral vein diameter was measured by ultrasound throughout the easy-going and struggle phase of apnea with GPI in eight divers in a sub-study. RESULTS After GPI, pulmonary volume increased by 0.8 ± 0.6 L above total lung capacity. The diameter of the superior caval (by 36 ± 17%) and intrathoracic part of the inferior caval vein decreased (by 21 ± 16%), while the diameters of the internal jugular (by 53 ± 34%), hepatic (by 28 ± 40%), abdominal part of the inferior caval (by 28 ± 28%), and femoral veins (by 65 ± 50%) all increased (P < 0.05). Blood volume of the internal jugular, the hepatic, the abdominal part of the inferior caval vein, and the combined common iliac and femoral veins increased by 145 ± 115, 80 ± 88, 61 ± 60, and 183 ± 197%, respectively. In the sub-study, femoral vein diameter increased by 44 ± 33% in the easy-going phase of apnea with GPI, subsequently decreasing by 20 ± 16% during the struggle phase. Electrical impedance remained unchanged over the thigh and forearm, thus excluding peripheral fluid extravasation. CONCLUSIONS GPI leads to heart and pulmonary vessel compression, resulting in redistribution of blood to extrathoracic capacitance veins proximal to venous valves. This is partially reversed by the onset of involuntary breathing movements.
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Affiliation(s)
- Tanja Mijacika
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia
| | - Daria Frestad
- Department of Cardiology, Copenhagen University Hospital, Hvidovre, University of Copenhagen, Copenhagen, Denmark
| | - Kasper Kyhl
- The Cardiac MRI Group, Department of Cardiology, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Otto Barak
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia.,Department of Physiology, Faculty of Medicine, University of Novi Sad, Novi Sad, Serbia
| | - Ivan Drvis
- University of Zagreb School of Kinesiology, Zagreb, Croatia
| | - Niels H Secher
- Department of Anesthesiology, The Copenhagen Muscle Research Center, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Ante Buca
- Department of Radiology, University Hospital Center, Split, Croatia
| | - Ante Obad
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia
| | - Zeljko Dujic
- Department of Integrative Physiology, University of Split School of Medicine, Šoltanska 2, 21000, Split, Croatia.
| | - Per Lav Madsen
- Department of Cardiology, Copenhagen University Hospital, Herlev, University of Copenhagen, Copenhagen, Denmark
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Ong T, Sobotka KS, Siew ML, Crossley KJ, van Vonderen JJ, Polglase GR, Hooper SB. The cardiovascular response to birth asphyxia is altered by the surrounding environment. Arch Dis Child Fetal Neonatal Ed 2016; 101:F540-F545. [PMID: 27059073 DOI: 10.1136/archdischild-2015-309596] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Revised: 03/10/2016] [Accepted: 03/14/2016] [Indexed: 11/04/2022]
Abstract
BACKGROUND A sustained bradycardia is used as a major indicator of severe perinatal asphyxia. However, lambs asphyxiated ex utero do not exhibit the same bradycardic response as lambs asphyxiated in utero. It is possible that the local in utero environment may influence the initial cardiovascular response to asphyxia. We assessed the effect of facial immersion in water on the cardiovascular response to birth asphyxia. METHODS Pregnant ewes (138±1 days gestation) were anaesthetised and fetuses were exteriorised and instrumented for measurement of cardiopulmonary haemodynamics. The lamb's head either remained in air (n=5) or was placed in water that was either warm (40±1°C; n=5) or at room temperature (21±1°C; n=5) before the umbilical cord was clamped to induce asphyxia. RESULTS Heart rate after bradycardia onset was reduced in lambs asphyxiated with their head in cool water (-34±2%) and warm water (-25±4%) compared with those in air (-11±5%; p<0.05). Similarly, the decrease in blood pressure was faster in lambs with water around the face compared with those in air. From 75 s after asphyxia onset, mean and end-diastolic carotid blood flow was higher in the group asphyxiated in air (25±4 mL/kg/min), compared with the groups in water (13±3 mL/kg/min, warm water; 16±2 mL/kg/min, cool water; p<0.05). CONCLUSIONS The cardiovascular response to birth asphyxia is altered by the presence and temperature of water surrounding the head. The previous understanding of the vagally mediated bradycardia associated with birth asphyxia may include components of the diving reflex.
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Affiliation(s)
- Tracey Ong
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Kristina S Sobotka
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Melissa L Siew
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Kelly J Crossley
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | | | - Graeme R Polglase
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
| | - Stuart B Hooper
- The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia.,Department of Obstetrics and Gynaecology, Monash University, Clayton, Victoria, Australia
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Golanov EV, Shiflett JM, Britz GW. Diving Response in Rats: Role of the Subthalamic Vasodilator Area. Front Neurol 2016; 7:157. [PMID: 27708614 PMCID: PMC5030511 DOI: 10.3389/fneur.2016.00157] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2016] [Accepted: 09/08/2016] [Indexed: 11/29/2022] Open
Abstract
Diving response (DR) is a powerful integrative response targeted toward survival of the hypoxic/anoxic conditions. Being present in all animals and humans, it allows to survive adverse conditions like diving. Earlier, we discovered that forehead stimulation affords neuroprotective effect, decreasing infarction volume triggered by permanent occlusion of the middle cerebral artery in rats. We hypothesized that cold stimulation of the forehead induces DR in rats, which, in turn, exerts neuroprotection. We compared autonomic [AP, heart rate (HR), cerebral blood flow (CBF)] and EEG responses to the known DR-triggering stimulus, ammonia stimulation of the nasal mucosa, cold stimulation of the forehead, and cold stimulation of the glabrous skin of the tail base in anesthetized rats. Responses in AP, HR, CBF, and EEG to cold stimulation of the forehead and ammonia vapors instillation into the nasal cavity were comparable and differed significantly from responses to the cold stimulation of the tail base. Excitotoxic lesion of the subthalamic vasodilator area (SVA), which is known to participate in CBF regulation and to afford neuroprotection upon excitation, failed to affect autonomic components of the DR evoked by forehead cold stimulation or nasal mucosa ammonia stimulation. We conclude that cold stimulation of the forehead triggers physiological response comparable to the response evoked by ammonia vapor instillation into nasal cavity, which is considered as stimulus triggering protective DR. These observations may explain the neuroprotective effect of the forehead stimulation. Data demonstrate that SVA does not directly participate in the autonomic adjustments accompanying DR; however, it is involved in diving-evoked modulation of EEG. We suggest that forehead stimulation can be employed as a stimulus capable of triggering oxygen-conserving DR and can be used for neuroprotective therapy.
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Affiliation(s)
- Eugene V. Golanov
- Department of Neurosurgery, The Houston Methodist Hospital, Houston, TX, USA
- Department of Neurosurgery, University of Mississippi Medical Center, Jackson, MS, USA
| | - James M. Shiflett
- Department of Neurosurgery, University of Mississippi Medical Center, Jackson, MS, USA
| | - Gavin W. Britz
- Department of Neurosurgery, The Houston Methodist Hospital, Houston, TX, USA
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28
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Anderson S, Chamberlain MR, Musgrove S, Partusch A, Tice KRJ, Thorp DB. Is V̇O 2 suppressed during nonapnoeic facial submersion? Appl Physiol Nutr Metab 2016; 41:1171-1176. [PMID: 27801599 DOI: 10.1139/apnm-2016-0268] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The mammalian dive response (DR) is described as oxygen-conserving based on measures of bradycardia, peripheral vasoconstriction, and decreased ventilation (V̇E). Using a model of simulated diving, this study examined the effect of nonapnoeic facial submersions (NAFS) on oxygen consumption (V̇O2). 19 participants performed four 2-min NAFS with 8 min of rest between each. Two submersions were performed in 5 °C water, 2 in 25 °C water. Heart rate (HR) was collected using chest strap monitors. A tube connected to the inspired port of a non-rebreathing valve allowed participants to breathe during facial submersion. Expired air was directed to a metabolic cart to determine V̇O2 and V̇E. Baseline (BL) HR, V̇O2, and V̇E values were determined by the average during the 2 min prior to facial submersion; cold shock response (CSR) values were the maximum during the first 30 s of facial submersion; and NAFS values were the minimum during the last 90 s of facial submersion. A 2-way repeated-measures ANOVA indicated that both HR and V̇E were greater during the CSR (92.5 ± 3.6 beats/min, 16.3 ± 0.8 L/min) compared with BL (78.9 ± 3.2 beats/min, 8.7 ± 0.4 L/min), while both were decreased from BL during the NAFS (60.0 ± 4.0 beats/min, 6.0 ± 0.4 L/min) (all, p < 0.05). HRCSR was higher and HRNAFS lower in 5 °C versus 25 °C water (p < 0.05), while V̇E was greater in 5 °C conditions (p < 0.05). V̇O2 exceeded BL during the CSR and decreased below BL during the NAFS (BL: 5.3 ± 0.1, CSR: 9.8 ± 0.4, NAFS: 3.1 ± 0.2 mL·kg-1·min-1, p < 0.05). The data illustrate that NAFS alone contributes to the oxygen conservation associated with the human DR.
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Affiliation(s)
- Sarah Anderson
- Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA.,Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA
| | - Maggie R Chamberlain
- Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA.,Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA
| | - Samantha Musgrove
- Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA.,Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA
| | - Antonia Partusch
- Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA.,Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA
| | - Keagan R J Tice
- Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA.,Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA
| | - David B Thorp
- Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA.,Department of Human Physiology, Gonzaga University, 502 E Boone Ave., Spokane, WA 99258, USA
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Regulation of brain blood flow and oxygen delivery in elite breath-hold divers. J Cereb Blood Flow Metab 2015; 35:66-73. [PMID: 25370857 PMCID: PMC4294396 DOI: 10.1038/jcbfm.2014.170] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 01/07/2023]
Abstract
The roles of involuntary breathing movements (IBMs) and cerebral oxygen delivery in the tolerance to extreme hypoxemia displayed by elite breath-hold divers are unknown. Cerebral blood flow (CBF), arterial blood gases (ABGs), and cardiorespiratory metrics were measured during maximum dry apneas in elite breath-hold divers (n=17). To isolate the effects of apnea and IBM from the concurrent changes on ABG, end-tidal forcing ('clamp') was then used to replicate an identical temporal pattern of decreasing arterial PO2 (PaO2) and increasing arterial PCO2 (PaCO2) while breathing. End-apnea PaO2 ranged from 23 to 37 mm Hg (30 ± 7 mm Hg). Elevation in mean arterial pressure was greater during apnea than during clamp reaching +54 ± 24% versus 34 ± 26%, respectively; however, CBF increased similarly between apnea and clamp (93.6 ± 28% and 83.4 ± 38%, respectively). This latter observation indicates that during the overall apnea period IBM per se do not augment CBF and that the brain remains sufficiently protected against hypertension. Termination of apnea was not determined by reduced cerebral oxygen delivery; despite 40% to 50% reductions in arterial oxygen content, oxygen delivery was maintained by commensurately increased CBF.
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Kjeld T, Rasmussen MR, Jattu T, Nielsen HB, Secher NH. Ischemic preconditioning of one forearm enhances static and dynamic apnea. Med Sci Sports Exerc 2014; 46:151-5. [PMID: 23846166 DOI: 10.1249/mss.0b013e3182a4090a] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
INTRODUCTION Ischemic preconditioning enhances ergometer cycling and swimming performance. We evaluated whether ischemic preconditioning of one forearm (four times for 5 min) also affects static breath hold and underwater swimming, whereas the effect of similar preconditioning on ergometer rowing served as control because the warm-up for rowing regularly encompasses intense exercise and therefore reduced muscle oxygenation. METHODS Six divers performed a dry static breath hold, 11 divers swam underwater in an indoor pool, and 14 oarsmen rowed "1000 m" on an ergometer. RESULTS Ischemic preconditioning reduced the forearm oxygen saturation from 65% ± 7% to 19% ± 7% (mean ± SD; P < 0.001), determined using spatially resolved near-infrared spectroscopy. During the breath hold (315 s, range = 280-375 s), forearm oxygenation decreased to 29% ± 10%; and in preparation for rowing, right thigh oxygenation decreased from 66% ± 7% to 33% ± 14% (P < 0.05). Ischemic preconditioning prolonged the breath hold from 279 ± 72 to 327 ± 39 s, and the underwater swimming distance from 110 ± 16 to 119 ± 14 m (P < 0.05) and also the rowing time was reduced (from 186.5 ± 3.6 to 185.7 ± 3.6 s; P < 0.05). CONCLUSIONS We conclude that while the effect of ischemic preconditioning (of one forearm) on ergometer rowing was minimal, probably because of reduced muscle oxygenation during the warm-up, ischemic preconditioning does enhance both static and dynamic apnea, supporting that muscle ischemia is an important preparation for physical activity.
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Affiliation(s)
- Thomas Kjeld
- The Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Denmark
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31
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Kjeld T, Jattu T, Nielsen HB, Goetze JP, Secher NH, Olsen NV. Release of erythropoietin and neuron-specific enolase after breath holding in competing free divers. Scand J Med Sci Sports 2014; 25:e253-7. [DOI: 10.1111/sms.12309] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2014] [Indexed: 11/30/2022]
Affiliation(s)
- T. Kjeld
- Department of Anesthesia (The Copenhagen Muscle Research Center); Rigshospitalet; Copenhagen Denmark
- Department of Cardiology; Rigshospitalet; Copenhagen Denmark
| | - T. Jattu
- Department of Anesthesia (The Copenhagen Muscle Research Center); Rigshospitalet; Copenhagen Denmark
| | - H. B. Nielsen
- Department of Anesthesia (The Copenhagen Muscle Research Center); Rigshospitalet; Copenhagen Denmark
| | - J. P. Goetze
- Department of Clinical Biochemistry; Rigshospitalet; Copenhagen Denmark
| | - N. H. Secher
- Department of Anesthesia (The Copenhagen Muscle Research Center); Rigshospitalet; Copenhagen Denmark
| | - N. V. Olsen
- Department of Neuroanesthesia; Rigshospitalet; Copenhagen Denmark
- Department of Neuroscience and Pharmacology; University of Copenhagen; Copenhagen Denmark
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Cross TJ, Kavanagh JJ, Breskovic T, Johnson BD, Dujic Z. Dynamic cerebral autoregulation is acutely impaired during maximal apnoea in trained divers. PLoS One 2014; 9:e87598. [PMID: 24498340 PMCID: PMC3911978 DOI: 10.1371/journal.pone.0087598] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 12/21/2013] [Indexed: 11/22/2022] Open
Abstract
Aims To examine whether dynamic cerebral autoregulation is acutely impaired during maximal voluntary apnoea in trained divers. Methods Mean arterial pressure (MAP), cerebral blood flow-velocity (CBFV) and end-tidal partial pressures of O2 and CO2 (PETO2 and PETCO2) were measured in eleven trained, male apnoea divers (28±2 yr; 182±2 cm, 76±7 kg) during maximal “dry” breath holding. Dynamic cerebral autoregulation was assessed by determining the strength of phase synchronisation between MAP and CBFV during maximal apnoea. Results The strength of phase synchronisation between MAP and CBFV increased from rest until the end of maximal voluntary apnoea (P<0.05), suggesting that dynamic cerebral autoregulation had weakened by the apnoea breakpoint. The magnitude of impairment in dynamic cerebral autoregulation was strongly, and positively related to the rise in PETCO2 observed during maximal breath holding (R2 = 0.67, P<0.05). Interestingly, the impairment in dynamic cerebral autoregulation was not related to the fall in PETO2 induced by apnoea (R2 = 0.01, P = 0.75). Conclusions This study is the first to report that dynamic cerebral autoregulation is acutely impaired in trained divers performing maximal voluntary apnoea. Furthermore, our data suggest that the impaired autoregulatory response is related to the change in PETCO2, but not PETO2, during maximal apnoea in trained divers.
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Affiliation(s)
- Troy J. Cross
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| | - Justin J. Kavanagh
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
| | - Toni Breskovic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Bruce D. Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Zeljko Dujic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
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Cross TJ, Kavanagh JJ, Breskovic T, Zubin Maslov P, Lojpur M, Johnson BD, Dujic Z. The Effects of Involuntary Respiratory Contractions on Cerebral Blood Flow during Maximal Apnoea in Trained Divers. PLoS One 2013; 8:e66950. [PMID: 23840561 PMCID: PMC3694127 DOI: 10.1371/journal.pone.0066950] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2013] [Accepted: 05/14/2013] [Indexed: 11/26/2022] Open
Abstract
The effects of involuntary respiratory contractions on the cerebral blood flow response to maximal apnoea is presently unclear. We hypothesised that while respiratory contractions may augment left ventricular stroke volume, cardiac output and ultimately cerebral blood flow during the struggle phase, these contractions would simultaneously cause marked ‘respiratory’ variability in blood flow to the brain. Respiratory, cardiovascular and cerebrovascular parameters were measured in ten trained, male apnoea divers during maximal ‘dry’ breath holding. Intrathoracic pressure was estimated via oesophageal pressure. Left ventricular stroke volume, cardiac output and mean arterial pressure were monitored using finger photoplethysmography, and cerebral blood flow velocity was obtained using transcranial ultrasound. The increasingly negative inspiratory intrathoracic pressure swings of the struggle phase significantly influenced the rise in left ventricular stroke volume (R2 = 0.63, P<0.05), thereby contributing to the increase in cerebral blood flow velocity throughout this phase of apnoea. However, these contractions also caused marked respiratory variability in left ventricular stroke volume, cardiac output, mean arterial pressure and cerebral blood flow velocity during the struggle phase (R2 = 0.99, P<0.05). Interestingly, the magnitude of respiratory variability in cerebral blood flow velocity was inversely correlated with struggle phase duration (R2 = 0.71, P<0.05). This study confirms the hypothesis that, on the one hand, involuntary respiratory contractions facilitate cerebral haemodynamics during the struggle phase while, on the other, these contractions produce marked respiratory variability in blood flow to the brain. In addition, our findings indicate that such variability in cerebral blood flow negatively impacts on struggle phase duration, and thus impairs breath holding performance.
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Affiliation(s)
- Troy J. Cross
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
- * E-mail:
| | - Justin J. Kavanagh
- Griffith Health Institute and Heart Foundation Research Centre, Griffith University, Gold Coast Campus, Queensland, Australia
| | - Toni Breskovic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Petra Zubin Maslov
- Department of Physiology, University of Split School of Medicine, Split, Croatia
| | - Mihajlo Lojpur
- Department of Anaesthesiology, Clinical Hospital Center Split, Split, Croatia
| | - Bruce D. Johnson
- Division of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota, United States of America
| | - Zeljko Dujic
- Department of Physiology, University of Split School of Medicine, Split, Croatia
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Schiffer TA, Larsen FJ, Lundberg JO, Weitzberg E, Lindholm P. Effects of dietary inorganic nitrate on static and dynamic breath-holding in humans. Respir Physiol Neurobiol 2012; 185:339-48. [PMID: 23099220 DOI: 10.1016/j.resp.2012.09.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 08/17/2012] [Accepted: 09/18/2012] [Indexed: 10/27/2022]
Abstract
Inorganic nitrate has been shown to reduce oxygen cost during exercise. Since the nitrate-nitrite-NO pathway is facilitated during hypoxia, we investigated the effects of dietary nitrate on oxygen consumption and cardiovascular responses during apnea. These variables were measured in two randomized, double-blind, placebo-controlled, crossover protocols at rest and ergometer exercise in competitive breath-hold divers. Subjects held their breath for predetermined times along with maximum effort apneas after two separate 3-day periods with supplementation of potassium nitrate/placebo. In contrast to our hypothesis, nitrate supplementation led to lower arterial oxygen saturation (SaO(2), 77 ± 3%) compared to placebo (80 ± 2%) during static apnea, along with lower end-tidal fraction of oxygen (FETO(2)) after 4 min of apnea (nitrate 6.9 ± 0.4% vs. placebo 7.6 ± 0.4%). Maximum apnea duration was shorter after nitrate (329 ± 13 s) compared to placebo (344 ± 13 s). During cycle ergometry nitrate had no effect on SaO(2), FETO(2) or maximum apnea duration. The negative effects of inorganic nitrate during static apnea may be explained by an attenuated diving response.
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Affiliation(s)
- Tomas A Schiffer
- Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.
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35
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Miyazawa T, Horiuchi M, Ichikawa D, Subudhi AW, Sugawara J, Ogoh S. Face cooling with mist water increases cerebral blood flow during exercise: effect of changes in facial skin blood flow. Front Physiol 2012; 3:308. [PMID: 22934059 PMCID: PMC3429079 DOI: 10.3389/fphys.2012.00308] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2012] [Accepted: 07/13/2012] [Indexed: 11/21/2022] Open
Abstract
Facial cooling (FC) increases cerebral blood flow (CBF) at rest and during exercise; however, the mechanism of this response remains unclear. The purpose of the present study was to test our hypothesis that FC causes facial vasoconstriction that diverts skin blood flow (SkBFface) toward the middle cerebral artery (MCA Vmean) at rest and to a greater extent during exercise. Nine healthy young subjects (20 ± 2 years) underwent 3 min of FC by fanning and spraying the face with a mist of cold water (~4°C) at rest and during steady-state exercise [heart rate (HR) of 120 bpm]. We focused on the difference between the averaged data acquired from 1 min immediately before FC and last 1 min of FC. SkBFface, MCA Vmean, and mean arterial blood pressure (MAP) were higher during exercise than at rest. As hypothesized, FC decreased SkBFface at rest (−32 ± 4%) and to a greater extent during exercise (−64 ± 10%, P = 0.012). Although MCA Vmean was increased by FC (Rest, +1.4 ± 0.5 cm/s; Exercise, +1.4 ± 0.6 cm/s), the amount of the FC-evoked changes in MCA Vmean at rest and during exercise differed among subjects. In addition, changes in MCA Vmean with FC did not correlate with concomitant changes in SkBFface (r = 0.095, P = 0.709). MAP was also increased by FC (Rest, +6.2 ± 1.4 mmHg; Exercise, +4.2 ± 1.2 mmHg). These findings suggest that the FC-induced increase in CBF during exercise could not be explained only by change in SkBFface.
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Affiliation(s)
- Taiki Miyazawa
- Center for Biomedical Engineering Research, Toyo University Kawagoe, Japan
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Nishiyasu T, Tsukamoto R, Kawai K, Hayashi K, Koga S, Ichinose M. Relationships between the extent of apnea-induced bradycardia and the vascular response in the arm and leg during dynamic two-legged knee extension exercise. Am J Physiol Heart Circ Physiol 2012; 302:H864-71. [DOI: 10.1152/ajpheart.00413.2011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Our aim was to test the hypothesis that apnea-induced hemodynamic responses during dynamic exercise in humans differ between those who show strong bradycardia and those who show only mild bradycardia. After apnea-induced changes in heart rate (HR) were evaluated during dynamic exercise, 23 healthy subjects were selected and divided into a large response group (L group; n = 11) and a small response group (S group; n = 12). While subjects performed a two-legged dynamic knee extension exercise at a work load that increased HR by 30 beats/min, apnea-induced changes in HR, cardiac output (CO), mean arterial pressure (MAP), arterial O2 saturation (SaO2), forearm blood flow (FBF), and leg blood flow (LBF) were measured. During apnea, HR in the L group (54 ± 2 beats/min) was lower than in the S group (92 ± 3 beats/min, P < 0.05). CO, SaO2, FBF, LBF, forearm vascular conductance (FVC), leg vascular conductance (LVC), and total vascular conductance (TVC) were all reduced, and MAP was increased in both groups, although the changes in CO, TVC, LBF, LVC, and MAP were larger in the L group than in the S group ( P < 0.05). Moreover, there were significant positive linear relationships between the reduction in HR and the reductions in TVC, LVC, and FVC. We conclude that individuals who show greater apnea-induced bradycardia during exercise also show greater vasoconstriction in both active and inactive muscle regions.
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Affiliation(s)
- Takeshi Nishiyasu
- Institute of Health and Sports Science, University of Tsukuba, Tsukuba
| | - Rina Tsukamoto
- Institute of Health and Sports Science, University of Tsukuba, Tsukuba
| | - Katsuhito Kawai
- Institute of Health and Sports Science, University of Tsukuba, Tsukuba
| | | | | | - Masashi Ichinose
- School of Business Administration, Meiji University, Tokyo, Japan
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Caspers C, Cleveland S, Schipke JD. Diving reflex: can the time course of heart rate reduction be quantified? Scand J Med Sci Sports 2010; 21:18-31. [PMID: 21083770 DOI: 10.1111/j.1600-0838.2010.01246.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
In this meta-analysis of diving bradycardia in humans, we sought to quantify any heart rate (HR) reduction using a relatively simple mathematical function. Using the terms "diving reflex,""diving bradycardia,""diving response,""diving plus heart rate," databases were searched. Data from the studies were fitted using HR=c+aexp(-(t-t(0))/τ), where c is the final HR, a is the HR decrease, τ is the time constant of HR decay, and t(0) is the time delay. Of 890 studies, 220 were given closer scrutiny. Only eight of these provided data obtained under comparable conditions. Apneic facial immersion decreased HR with τ=10.4 s and in air alone it was less pronounced and slower (τ=16.2 s). The exponential function fitted the time course of HR decrease closely (r(2)>0.93). The fit was less adequate for apneic-exercising volunteers. During apnea both with and without face immersion, HR decreases along a monoexponential function with a characteristic time constant. HR decrease during exercise with and without face immersion could not readily be described with a simple function: the parasympathetic reaction was partially offset by some sympathetic activity. Thus, we succeeded in quantifying the early time course of diving bradycardia. It is concluded that the diving reflex is useful to diagnose the integrity of efferent cardiovascular autonomic pathways.
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Affiliation(s)
- C Caspers
- Research Group Experimental Surgery, University Hospital Düsseldorf, Düsseldorf, Germany
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