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SCUBA Diving in Adult Congenital Heart Disease. J Cardiovasc Dev Dis 2023; 10:jcdd10010020. [PMID: 36661915 PMCID: PMC9863475 DOI: 10.3390/jcdd10010020] [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: 11/30/2022] [Revised: 12/29/2022] [Accepted: 01/01/2023] [Indexed: 01/05/2023] Open
Abstract
Conventionally, scuba diving has been discouraged for adult patients with congenital heart disease (ACHD). This restrictive sports advice is based on expert opinion in the absence of high-quality diving-specific studies. However, as survival and quality of life in congenital heart disease (CHD) patients have dramatically improved in the last decades, a critical appraisal whether such restrictive sports advice is still applicable is warranted. In this review, the cardiovascular effects of diving are described and a framework for the work-up for ACHD patients wishing to engage in scuba diving is provided. In addition, diving recommendations for specific CHD diagnostic groups are proposed.
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Castagna O, Blatteau JE, Druelle A, Amara J, Lacour JR. Oxygen uptake ( V ˙ O 2) and pulmonary ventilation ( V ˙ E) during military surface fin swimming in a swimming flume: Effects of surface immersion. Front Physiol 2023; 14:1145204. [PMID: 36950295 PMCID: PMC10025479 DOI: 10.3389/fphys.2023.1145204] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Accepted: 02/21/2023] [Indexed: 03/08/2023] Open
Abstract
Introduction: During military fin swimming, we suspected that oxygen uptake ( V ˙ O2) and pulmonary ventilation ( V ˙ E) might be much higher than expected. In this framework, we compared these variables in the responses of trained military divers during land cycling and snorkeling exercises. Methods: Eighteen male military divers (32.3 ± 4.2 years; 178.0 ± 5.0 cm; 76.4 ± 3.4 kg; 24.1 ± 2.1 kg m-2) participated in this study. They performed two test exercises on two separate days: a maximal incremental cycle test (land condition), and an incremental fin swimming (fin condition) in a motorized swimming flume. Results: The respective fin and land V ˙ O2max were 3,701 ± 39 mL min-1 and 4,029 ± 63 mL min-1 (p = 0.07), these values were strongly correlated (r 2 = 0.78 p < 0.01). Differences in V ˙ O2max between conditions increased relative to l; V ˙ O2max (r 2 = 0.4 p = 0.01). Fin V ˙ E max values were significantly lower than land V ˙ E max values (p = 0.01). This result was related to both the significantly lower fin Vt and f (p < 0.01 and <0.04, respectively). Consequently, the fin V ˙ E max / V ˙ O2max ratios were significantly lower than the corresponding ratios for land values (p < 0.01), and the fin and land V ˙ E max were not correlated. Other parameters measured at exhaustion-PaO2, PaCO2, and SO2 - were similar in fin and land conditions. Furthermore, no significant differences between land and fin conditions were observed for peak values for heart rate, blood lactate concentration, and respiratory exchange ratio R. Conclusion: Surface immersion did not significantly reduce the V ˙ O2max in trained divers relative to land conditions. As long as V ˙ O2 remained below V ˙ O2max , the V ˙ E values were identical in the two conditions. Only at V ˙ O2max was V ˙ E higher on land. Although reduced by immersion, V ˙ E max provided adequate pulmonary gas exchange during maximal fin swimming.
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Affiliation(s)
- Olivier Castagna
- Underwater research team—ERRSO, Military biomedical research institute-IRBA, Toulon, France
- LAMHESS (UPR 6312), Université de Nice, Nice, France
| | - Jean-Eric Blatteau
- Department of underwater and hyperbaric medicine (SMHEP), Ste Anne military hospital (HIA Ste Anne), Toulon, France
- *Correspondence: Jean-Eric Blatteau,
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Diving ergospirometry with suspended weights: breathing- and fin-swimming style matter. Eur J Appl Physiol 2022; 122:2463-2473. [PMID: 36006480 PMCID: PMC9560930 DOI: 10.1007/s00421-022-05009-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 07/05/2022] [Indexed: 11/06/2022]
Abstract
Purpose Scuba diving is a complex condition including elevated ambient pressure, limited air supply, increased breathing work, and unfamiliar fin-swimming. Earlier approaches to assess diving specific data did not comprehensively address these aspects. We first present an underwater ergospirometry system and then test the hypothesis that both breathing characteristics and fin-swimming style affect the air consumption. Methods/Participants A suspended-weights ergospirometry system was mounted inside a hyperbaric chamber. Ergo group: 25 divers (24.6 ± 4.1 years); three set-ups: dry normobaric cycling (75–225 W), dry cycling at 20 m simulated depth (75–225 W), fin-swimming at 20 m (5–8 kg suspended weights). Style group: 20 other divers (24.6 ± 4.1 years): fin-swimming at 20 m (5–8 kg) with regard to ventilation (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙E) and fin-swimming style. Results Ergo group: linear heart rate and oxygen uptake (\documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2) increases with both 50 W-bicycle steps and suspended-weights ergometry (r = 0.97). During hyperbaric conditions, \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙E was less increased versus normobaric conditions. Style group: the more efficient hip/thigh-oriented style shifted towards the knee/calf-oriented style. \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙E and \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2 were higher in beginners (< 100 dives) versus advanced divers (≥ 100 dives). Significant differences on the 5 kg-step: \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙E: 31.5 ± 7.1 l/min vs. 23.7 ± 5.9 l/min and \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙O2: 1.6 ± 0.3 l/min vs. 1.2 ± 0.3 l/min. A comparison is presented, in addition to illustrate the impact of differences in breathing characteristics and fin-swimming style. Conclusions Diving ergospirometry with suspended weights in a hyperbaric chamber allows for comprehensive studies. Little diving experience in terms of breathing characteristics and fin-swimming style significantly increases \documentclass[12pt]{minimal}
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\begin{document}$$\dot{V}$$\end{document}V˙E thereby increasing the risk of running-out-of-air.
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Rives S, Schmid B, Chaumet G, Brégeon F, Boussuges A. Changes in Diaphragmatic Function Induced by an Increased Inspiratory Load Experienced by Military Divers: An Ultrasound Study. Front Physiol 2021; 12:756533. [PMID: 34916955 PMCID: PMC8670941 DOI: 10.3389/fphys.2021.756533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/09/2021] [Indexed: 11/29/2022] Open
Abstract
Background: Inspiratory loading is experienced by military divers when they use rebreather device. Our objective was to assess the changes in diaphragm function induced by an increase in inspiratory load at values similar to those experienced by divers in real life. Methods: We recorded the excursion and the thickness of the right hemidiaphragm in 22 healthy male volunteers under inspiratory load conditions, using ultrasound in B- and M-mode. The measurements were performed at tidal volume and during breathing at 50% of inspiratory capacity. The breathing rate was regulated and similar in the various sessions with and without load. Results: The rebreather device used by French military divers leads to an increase in inspiratory load of close to 30 cmH2O. Consequently, the session under load was performed using a device set to this threshold. Significant increases in the excursion and the thickening fraction of the diaphragm were observed between the sessions at tidal volume and at high volume. With addition of the inspiratory load, the excursion of the right hemidiaphragm increased significantly from 2.3 to 3.4cm at tidal volume and from 3.9 to 4.7cm at high volume. The thickening fraction increased significantly from 30.4 to 76.6% at tidal volume and from 70 to 123% at high volume. The statistical analysis demonstrated that assessment of the changes of the thickening fraction during breathing at tidal volume was the most relevant marker to assess the impact of the inspiratory load on the diaphragm. Conclusion: Diaphragm ultrasound can be used to assess the changes in the diaphragm contraction pattern secondary to an increase in the respiratory load that can be generated by use a diving apparatus. The recording of the changes of the motion, and more importantly of the thickness of the diaphragm, during the breathing cycle is able to provide relevant information regarding the inspiratory load.
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Affiliation(s)
- Sarah Rives
- ERRSO, Institut de Recherche Biomédicale des Armées (IRBA), Toulon, France.,Center for Cardiovascular and Nutrition Research (C2VN), INSERM, INRAE, Aix Marseille Université, Marseille, France
| | - Bruno Schmid
- ERRSO, Institut de Recherche Biomédicale des Armées (IRBA), Toulon, France
| | | | - Fabienne Brégeon
- Service d'Explorations Fonctionnelles Respiratoires, CHU Nord, Assistance Publique des Hôpitaux de Marseille et Aix Marseille Univ, IRD, APHM, MEPHIIHU-Méditerranée Infection, Marseille, France
| | - Alain Boussuges
- ERRSO, Institut de Recherche Biomédicale des Armées (IRBA), Toulon, France.,Center for Cardiovascular and Nutrition Research (C2VN), INSERM, INRAE, Aix Marseille Université, Marseille, France.,Service d'Explorations Fonctionnelles Respiratoires, CHU Nord, Assistance Publique des Hôpitaux de Marseille et Aix Marseille Univ, IRD, APHM, MEPHIIHU-Méditerranée Infection, Marseille, France
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Abstract
PURPOSE Water immersion adds additional drag and metabolic demand for limb movement with respect to air, but its effect on the internal metabolic power (Ėint) of cycling is unknown. We aimed at quantifying the increase in Ėint during underwater cycling with respect to dry conditions at different pedaling rates. METHODS 12 healthy subjects (4 females) pedaled on a waterproof cycle ergometer in an experimental pool that was either empty (DRY) or filled with tap water at 30.8 ± 0.6 °C (WET). Four different pedal cadences (fp) were studied (40, 50, 60 and 70 rpm) at 25, 50, 75 and 100 W. The metabolic power at steady state was measured via open circuit respirometry and Ėint was calculated as the metabolic power extrapolated for 0 W. RESULTS Ėint was significantly higher in WET than in DRY at 50, 60 and 70 rpm (81 ± 31 vs 32 ± 30 W, 167 ± 35 vs 50 ± 29 W, 311 ± 51 vs 81 ± 30 W, respectively, all p < 0.0001), but not at 40 rpm (16 ± 5 vs 11 ± 17 W, p > 0.99). Ėint increased with the third power of fp both in WET and DRY (R2 = 0.49 and 0.91, respectively). CONCLUSION Water drag increased Ėint, although limbs unloading via the Archimedes' principle and limbs shape could be potential confounding factors. A simple formula was developed to predict the increase in mechanical power in dry conditions needed to match the rate of energy expenditure during underwater cycling: 44 fp3 - 7 W, where fp is expressed in hertz.
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Affiliation(s)
- Giovanni Vinetti
- Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy Center for Research and Education in Special Environments, Department of Exercise and Nutrition Sciences, University at Buffalo, Buffalo, NY Department of Anaesthesiology, Clinical Pharmacology, Intensive Care and Emergency Medicine, University of Geneva, Geneva, Switzerland
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Cross TJ, Gideon EA, Morris SJ, Coriell CL, Hubbard CD, Duke JW. A comparison of methods used to quantify the work of breathing during exercise. J Appl Physiol (1985) 2021; 131:1123-1133. [PMID: 34410846 DOI: 10.1152/japplphysiol.00411.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The mechanical work of breathing (Wb) is an insightful tool used to assess respiratory mechanics during exercise. There are several different methods used to calculate the Wb, however, each approach having its own distinct advantages/disadvantages. To date, a comprehensive assessment of the differences in the components of Wb between these methods is lacking. We therefore sought to compare the values of Wb during graded exercise as determined via the four most popular methods: 1) pressure-volume integration; 2) the Hedstrand diagram; 3) the Otis diagram; and the 4) modified Campbell diagram. Forty-two participants (30 ± 15 yr; 16 women) performed graded cycling to volitional exhaustion. Esophageal pressure-volume loops were obtained throughout exercise. These data were used to calculate the total Wb and, where possible, its subcomponents of inspiratory and expiratory, resistive and elastic Wb, using each of the four methods. Our results demonstrate that the components of Wb were indeed different between methods across the minute ventilations engendered by graded exercise. Importantly, however, no systematic pattern in these differences could be observed. Our findings indicate that the values of Wb obtained during exercise are uniquely determined by the specific method chosen to compute its value-no two methods yield identical results. Because there is currently no "gold-standard" for measuring the Wb, it is emphasized that future investigators be cognizant of the limitations incurred by their chosen method, such that observations made by others may be interpreted with greater context, and transparency.NEW & NOTEWORTHY The measurement of the work of breathing (Wb) during exercise provides us with deep insights into respiratory (patho)physiology, and sheds light on the putative factors which lead to respiratory muscle fatigue. There are 4 popular methods available to determine the Wb. Our study demonstrates that no two of these methods produce identical values of Wb during exercise. This paper also discusses the practical and theoretical limitations of each method.
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Affiliation(s)
- Troy J Cross
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia.,Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
| | - Elizabeth A Gideon
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Sarah J Morris
- Faculty of Medicine and Health, University of Sydney, Sydney, New South Wales, Australia
| | - Catherine L Coriell
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Colin D Hubbard
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
| | - Joseph W Duke
- Department of Biological Sciences, Northern Arizona University, Flagstaff, Arizona
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Dreyer S, Schneppendahl J, Moeller F, Koch A, Muth T, Schipke JD. An Updated Narrative Review on Ergometric Systems Applied to Date in Assessing Divers' Fitness. Healthcare (Basel) 2021; 9:1044. [PMID: 34442180 PMCID: PMC8394438 DOI: 10.3390/healthcare9081044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 08/09/2021] [Accepted: 08/10/2021] [Indexed: 11/18/2022] Open
Abstract
Many recreational divers suffer medical conditions, potentially jeopardizing their safety. To scale down risks, medical examinations are mandatory and overwhelmingly performed using bicycle ergometry, which overlooks some important aspects of diving. Searching ergometric systems that better address the underwater environment, a systematic literature search was conducted using the keywords 'diving', 'fitness', 'ergometry', and 'exertion'. All presented alternative systems found convincingly describe a greatly reduced underwater physical performance. Thus, if a diver's workload in air should already be limited, he/she will suffer early from fatigue, risking a diving incident. How to assess fitness? Performance diagnostics in sports is always specific for a modality or movement. Therefore, professional scuba divers should be tested when fin-swimming underwater. For the vast number of recreational divers, the current screening can likely not be replaced. However, to prevent accidents, divers need to understand and be able to improve factors that limit their physical performance underwater. Other systems, presented here, will continue to be important tools in underwater research.
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Affiliation(s)
- Sven Dreyer
- Hyperbaric Oxygen Therapy, University Hospital Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany; (S.D.); (J.S.)
| | - Johannes Schneppendahl
- Hyperbaric Oxygen Therapy, University Hospital Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany; (S.D.); (J.S.)
| | - Fabian Moeller
- Department of Exercise Physiology, Institute of Exercise Training and Sport Informatics, German Sport University Cologne, 50933 Cologne, Germany;
| | - Andreas Koch
- German Naval Medical Institute, Maritime Medicine, 24119 Kronshagen, Germany;
| | - Thomas Muth
- Institute of Occupational, Social and Environmental Medicine, Medical Faculty and University Hospital Düsseldorf, Heinrich-Heine-University, 40225 Düsseldorf, Germany;
| | - Jochen D. Schipke
- Forschungsgruppe Experimentelle Chirurgie, Universitäts-Klinikum Düsseldorf, Moorenstrasse 5, 40225 Düsseldorf, Germany
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Wheelock CE, Hess HW, Johnson BD, Schlader ZJ, Clemency BM, St James E, Hostler D. Endurance and Resistance Respiratory Muscle Training and Aerobic Exercise Performance in Hypobaric Hypoxia. Aerosp Med Hum Perform 2020; 91:776-784. [PMID: 33187563 DOI: 10.3357/amhp.5624.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
INTRODUCTION: Hypoxia-induced hyperventilation is an effect of acute altitude exposure, which may lead to respiratory muscle fatigue and secondary locomotor muscle fatigue. The purpose of this study was to determine if resistive and/or endurance respiratory muscle training (RRMT and ERMT, respectively) vs. placebo respiratory muscle training (PRMT) improve cycling performance at altitude.METHODS: There were 24 subjects who were assigned to PRMT (N 8), RRMT (N 8), or ERMT (N 8). Subjects cycled to exhaustion in a hypobaric chamber decompressed to 3657 m (12,000 ft) at an intensity of 55% sea level maximal oxygen consumption (Vo2max) before and after respiratory muscle training (RMT). Additionally, subjects completed a Vo2max, pulmonary function, and respiratory endurance test (RET) before and after RMT. All RMT protocols consisted of three 30-min training sessions per week for 4 wk.RESULTS: The RRMT group increased maximum inspiratory (PImax) and expiratory (PEmax) mouth pressure after RMT (PImax: 117.7 11.6 vs. 162.6 20.0; PEmax: 164.0 33.2 vs. 216.5 44.1 cmH₂O). The ERMT group increased RET after RMT (5.2 5.2 vs.18.6 16.9 min). RMT did not improve Vo2max in any group. Both RRMT and ERMT groups increased cycling time to exhaustion (RRMT: 35.9 17.2 vs. 45.6 22.2 min and ERMT: 33.8 9.6 vs. 42.9 27.0 min).CONCLUSION: Despite different improvements in pulmonary function, 4 wk of RRMT and ERMT both improved cycle time to exhaustion at altitude.Wheelock CE, Hess HW, Johnson BD, Schlader ZJ, Clemency BM, St. James E, Hostler D. Endurance and resistance respiratory muscle training and aerobic exercise performance in hypobaric hypoxia. Aerosp Med Hum Perform. 2020; 91(10):776784.
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Hostler D, Pendergast DR. Respiratory Responses during Exercise in Self-contained Breathing Apparatus among Firefighters and Nonfirefighters. Saf Health Work 2018; 9:468-472. [PMID: 30559997 PMCID: PMC6284167 DOI: 10.1016/j.shaw.2018.02.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 09/08/2017] [Accepted: 02/09/2018] [Indexed: 11/28/2022] Open
Abstract
Background Firefighters are required to use self-contained breathing apparatus (SCBA), which impairs ventilatory mechanics. We hypothesized that firefighters have elevated arterial CO2 when using SCBA. Methods Firefighters and controls performed a maximal exercise test on a cycle ergometer and two graded exercise tests (GXTs) at 25%, 50%, and 70% of their maximal aerobic power, once with a SCBA facemask and once with protective clothing and full SCBA. Results Respiratory rate increased more in controls than firefighters. Heart rate increased as a function of oxygen consumption (V.O2) more in controls than firefighters. End-tidal CO2 (ETCO2) during the GXTs was not affected by work rate in either group for either condition but was higher in firefighters at all work rates in both GXTs. SCBA increased ETCO2 in controls but not firefighters. Conclusions The present study showed that when compared to controls, firefighters’ hypoventilate during a maximal test and GXT. The hypoventilation resulted in increased ETCO2, and presumably increased arterial CO2, during exertion. It is proposed that firefighters have altered CO2 sensitivity due to voluntary hypoventilation during training and work. Confirmation of low CO2 sensitivity and the consequence of this on performance and long-term health remain to be determined.
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Affiliation(s)
- David Hostler
- SUNY University at Buffalo, Department of Exercise and Nutrition Sciences, Center for Research and Education in Special Environments (CRESE), USA
| | - David R Pendergast
- SUNY University at Buffalo, Department of Physiology and Biophysics, USA
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Castagna O, Regnard J, Gempp E, Louge P, Brocq FX, Schmid B, Desruelle AV, Crunel V, Maurin A, Chopard R, MacIver DH. The Key Roles of Negative Pressure Breathing and Exercise in the Development of Interstitial Pulmonary Edema in Professional Male SCUBA Divers. SPORTS MEDICINE-OPEN 2018; 4:1. [PMID: 29299780 PMCID: PMC5752643 DOI: 10.1186/s40798-017-0116-x] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/27/2017] [Accepted: 12/17/2017] [Indexed: 12/12/2022]
Abstract
Background Immersion pulmonary edema is potentially a catastrophic condition; however, the pathophysiological mechanisms are ill-defined. This study assessed the individual and combined effects of exertion and negative pressure breathing on the cardiovascular system during the development of pulmonary edema in SCUBA divers. Methods Sixteen male professional SCUBA divers performed four SCUBA dives in a freshwater pool at 1 m depth while breathing air at either a positive or negative pressure both at rest or with exercise. Echocardiography and lung ultrasound were used to assess the cardiovascular changes and lung comet score (a measure of interstitial pulmonary edema). Results The ultrasound lung comet score was 0 following both the dives at rest regardless of breathing pressure. Following exercise, the mean comet score rose to 4.2 with positive pressure breathing and increased to 15.1 with negative pressure breathing. The development of interstitial pulmonary edema was significantly related to inferior vena cava diameter, right atrial area, tricuspid annular plane systolic excursion, right ventricular fractional area change, and pulmonary artery pressure. Exercise combined with negative pressure breathing induced the greatest changes in these cardiovascular indices and lung comet score. Conclusions A diver using negative pressure breathing while exercising is at greatest risk of developing interstitial pulmonary edema. The development of immersion pulmonary edema is closely related to hemodynamic changes in the right but not the left ventricle. Our findings have important implications for divers and understanding the mechanisms of pulmonary edema in other clinical settings.
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Affiliation(s)
- Olivier Castagna
- Underwater Research Team (ERRSO) from the Military Biomedical Research Institute (IRBA), Toulon, France.,Laboratory of Human Motricity, Education Sport and Health, LAMHESS (EA 6312), Toulon, France
| | - Jacques Regnard
- EA3920, University Bourgogne Franche-Comté and University Hospitals, Besançon, France
| | | | - Pierre Louge
- Department of Hyperbaric Medicine, HIA St Anne Military Hospital, Toulon, France
| | | | - Bruno Schmid
- Underwater Research Team (ERRSO) from the Military Biomedical Research Institute (IRBA), Toulon, France
| | - Anne-Virginie Desruelle
- Underwater Research Team (ERRSO) from the Military Biomedical Research Institute (IRBA), Toulon, France
| | - Valentin Crunel
- Underwater Research Team (ERRSO) from the Military Biomedical Research Institute (IRBA), Toulon, France
| | - Adrien Maurin
- Underwater Research Team (ERRSO) from the Military Biomedical Research Institute (IRBA), Toulon, France
| | - Romain Chopard
- Department of Cardiology EA3920, Franche Comté University and University Hospital, Besançon, France
| | - David Hunter MacIver
- Biological Physics Group, University of Manchester, Manchester, UK. .,Musgrove Park, Taunton & Somerset Hospital, Taunton, UK.
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Pendergast DR, Moon RE, Krasney JJ, Held HE, Zamparo P. Human Physiology in an Aquatic Environment. Compr Physiol 2015; 5:1705-50. [PMID: 26426465 DOI: 10.1002/cphy.c140018] [Citation(s) in RCA: 99] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Water covers over 70% of the earth, has varying depths and temperatures and contains much of the earth's resources. Head-out water immersion (HOWI) or submersion at various depths (diving) in water of thermoneutral (TN) temperature elicits profound cardiorespiratory, endocrine, and renal responses. The translocation of blood into the thorax and elevation of plasma volume by autotransfusion of fluid from cells to the vascular compartment lead to increased cardiac stroke volume and output and there is a hyperperfusion of some tissues. Pulmonary artery and capillary hydrostatic pressures increase causing a decline in vital capacity with the potential for pulmonary edema. Atrial stretch and increased arterial pressure cause reflex autonomic responses which result in endocrine changes that return plasma volume and arterial pressure to preimmersion levels. Plasma volume is regulated via a reflex diuresis and natriuresis. Hydrostatic pressure also leads to elastic loading of the chest, increasing work of breathing, energy cost, and thus blood flow to respiratory muscles. Decreases in water temperature in HOWI do not affect the cardiac output compared to TN; however, they influence heart rate and the distribution of muscle and fat blood flow. The reduced muscle blood flow results in a reduced maximal oxygen consumption. The properties of water determine the mechanical load and the physiological responses during exercise in water (e.g. swimming and water based activities). Increased hydrostatic pressure caused by submersion does not affect stroke volume; however, progressive bradycardia decreases cardiac output. During submersion, compressed gas must be breathed which introduces the potential for oxygen toxicity, narcosis due to nitrogen, and tissue and vascular gas bubbles during decompression and after may cause pain in joints and the nervous system.
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Affiliation(s)
- David R Pendergast
- Center for Research and Education in Special Environments, University at Buffalo, Buffalo, New York, USA
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York, USA
| | - Richard E Moon
- Center for Hyperbaric Medicine and Environmental Physiology, Duke University, Durham, North Carolina, USA
| | - John J Krasney
- Department of Physiology and Biophysics, University at Buffalo, Buffalo, New York, USA
| | - Heather E Held
- Biomedical Hyperbarics Research Laboratory, Molecular Pharmacology and Physiology, College of Medicine, University of South Florida, Tampa, Florida, USA
| | - Paola Zamparo
- Department of Neurological and Movement Sciences, University of Verona, Verona, Italy
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Held HE, Pendergast DR. The effects of respiratory muscle training on respiratory mechanics and energy cost. Respir Physiol Neurobiol 2014; 200:7-17. [PMID: 24816143 DOI: 10.1016/j.resp.2014.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 04/25/2014] [Accepted: 05/02/2014] [Indexed: 11/16/2022]
Abstract
Resistance respiratory muscle training (RRMT) increases respiratory muscle strength and can increase swimming endurance time by as much as 85%. The purpose of this study was to examine potential mechanisms by which RRMT improves exercise endurance. Eight healthy adult male scuba divers underwent experiments in a hyperbaric chamber at sea level (1 atmosphere absolute (ATA)), 2.7 ATA and 4.6 ATA, both dry and fully submersed. Subjects rested, exercised, and rested while mimicking their own exercise breathing (ISEV). Airway resistance (R(aw)), exhaled nitric oxide output (V˙(NO)), and respiratory duty cycle (T(I)/T(Tot)) were determined before and after four weeks of RRMT. RRMT decreased T(I)/T(Tot) (-10% at rest at 1 ATA), V˙(O2) (-17% at 2.7 ATA during submersed exercise), V˙(E) (-6% at 2.7 ATA during submersed exercise), and R(aw) (-34% inspiratory at 4.6 ATA submersed, -38% expiratory at 2.7 ATA dry), independent of changes in V˙(NO). Most importantly, respiratory muscle efficiency increased (+83% at 2.7 ATA submersed).
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Affiliation(s)
- Heather E Held
- Center for Research and Education in Special Environments, Department of Physiology and Biophysics, State University of New York at Buffalo, 16 Sherman Annex, Buffalo, NY 14260, United States.
| | - David R Pendergast
- Center for Research and Education in Special Environments, Department of Physiology and Biophysics, State University of New York at Buffalo, 16 Sherman Annex, Buffalo, NY 14260, United States
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Rubini A, Porzionato A, Sarasin G, Zara S, Macchi V, Camporesi E, Bosco G. Hyperbaric air exposure at 2.5 ATA does not affect respiratory mechanics and lung histology in the rat. Lung 2014; 192:609-14. [PMID: 24691890 DOI: 10.1007/s00408-014-9576-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Accepted: 03/14/2014] [Indexed: 10/25/2022]
Abstract
BACKGROUND We previously demonstrated that the exposure to hyperbaric hyperoxia increased respiratory system elastance and both the "ohmic" and viscoelastic components of inspiratory resistances, probably because of increased oxygen tension toxic effects. We presently investigated the possible consequences of a single exposure to 2.5-atmospheres absolute air (hyperbarism) lasting 90 min. METHODS We used the end-inflation occlusion method on anesthetized rats after about 15 min from previous exposure to hyperbarism. The method allows the measurements of respiratory system elastance and of the ohmic and viscoelastic components of airway resistance, which respectively depend on the Newtonian pressure dissipation due to the ohmic airway resistance to airflow and on the viscoelastic pressure dissipation caused by respiratory system tissue stress relaxation. The expressions of inducible NO synthase (iNOS) and endothelial NO synthase (eNOS) in the lung's tissues were also investigated, together with the histological characteristics of lung tissue. Data were compared with those obtained in control animals and in previously studied animals exposed to hyperoxic hyperbarism. RESULTS Unlike with hyperoxic hyperbarism, hyperbarism per se did not change significantly the parameters of respiratory mechanics in the control animals (respiratory system elastance and ohmic and viscoelastic resistances were 2.01 ± 0.17 vs. 1.74 ± 0.08 cm H(2)O/ml, and 0.13 ± 0.02 vs. 0.13 ± 0.03 and 0.425 ± 0.04 vs. 0.33 ± 0.03 cm H(2)O/ml s(-1) in control vs. experimental animals, respectively, none significantly different), nor did it induce evident effects on lung histology. An increment of both iNOS and eNOS expressions was documented instead (0.50 ± 0.05 vs. 0.75 ± 0.07 and 1.04 ± 0.1 and 1.4 ± 0.15, respectively). CONCLUSION Our results indicate that, at variance with hyperoxic hyperbarism, the acute exposure to only hyperbarism does not affect either the elastic or the resistive respiratory system properties, or lung histology.
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Affiliation(s)
- Alessandro Rubini
- Department of Biomedical Sciences, Section Physiology, University of Padova, Via Marzolo, 3, 35100, Padua, Italy,
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Boussuges A, Rostain JC. What cardiovascular changes during SCUBA diving? Acta Physiol (Oxf) 2013; 209:9-10. [PMID: 23764211 DOI: 10.1111/apha.12136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
| | - J.-C. Rostain
- UMR MD2; Aix Marseille University (AMU); Marseille; France
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