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Taboni A, Fagoni N, Fontolliet T, Vinetti G, Ferretti G. Baroreflex dynamics during the rest to exercise transient in acute normobaric hypoxia in humans. Eur J Appl Physiol 2024:10.1007/s00421-024-05485-4. [PMID: 38656378 DOI: 10.1007/s00421-024-05485-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2024] [Accepted: 03/26/2024] [Indexed: 04/26/2024]
Abstract
PURPOSE We hypothesised that during a rest-to-exercise transient in hypoxia (H), compared to normoxia (N), (i) the initial baroreflex sensitivity (BRS) decrease would be slower and (ii) the fast heart rate (HR) and cardiac output (CO) response would have smaller amplitude (A1) due to lower vagal activity in H than N. METHODS Ten participants performed three rest-to-50 W exercise transients on a cycle-ergometer in N (ambient air) and three in H (inspired fraction of O2 = 0.11). R-to-R interval (RRi, by electrocardiography) and blood pressure profile (by photo-plethysmography) were recorded non-invasively. Analysis of the latter provided mean arterial pressure (MAP) and stroke volume (SV). CO = HR·SV. BRS was calculated by modified sequence method. RESULTS Upon exercise onset in N, MAP fell to a minimum (MAPmin) then recovered. BRS decreased immediately from 14.7 ± 3.6 at rest to 7.0 ± 3.0 ms mmHg-1 at 50 W (p < 0.01). The first BRS sequence detected at 50 W was 8.9 ± 4.8 ms mmHg-1 (p < 0.05 vs. rest). In H, MAP showed several oscillations until reaching a new steady state. BRS decreased rapidly from 10.6 ± 2.8 at rest to 2.9 ± 1.5 ms mmHg-1 at 50 W (p < 0.01), as the first BRS sequence at 50 W was 5.8 ± 2.6 ms mmHg-1 (p < 0.01 vs. rest). CO-A1 was 2.96 ± 1.51 and 2.31 ± 0.94 l min-1 in N and H, respectively (p = 0.06). HR-A1 was 7.7 ± 4.6 and 7.1 ± 5.9 min-1 in N and H, respectively (p = 0.81). CONCLUSION The immediate BRS decrease in H, coupled with similar rapid HR and CO responses, is compatible with a withdrawal of residual vagal activity in H associated with increased sympathetic drive.
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Affiliation(s)
- Anna Taboni
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, Brescia, Italy.
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy.
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland.
| | - Nazzareno Fagoni
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, Brescia, Italy
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland
| | - Timothée Fontolliet
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland
| | - Giovanni Vinetti
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, Brescia, Italy
- Institute of Mountain Emergency Medicine, Eurac Research, Bolzano, Italy
| | - Guido Ferretti
- Department of Molecular and Translational Medicine, University of Brescia, Viale Europa 11, Brescia, Italy
- Department of Anaesthesiology, Pharmacology, Intensive Care, and Emergencies, University of Geneva, Geneva, Switzerland
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Castagna O, Druelle A, Michoud G, Prevautel T, Lacour JR. Individual Changes in Respiratory Compliance Upon Immersion May Predict Susceptibility to Immersion Pulmonary Edema. SPORTS MEDICINE - OPEN 2023; 9:39. [PMID: 37261587 DOI: 10.1186/s40798-023-00590-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Received: 04/01/2023] [Accepted: 05/25/2023] [Indexed: 06/02/2023]
Abstract
BACKGROUND Immersion pulmonary edema (IPE) is a frequent diving accident, and it is the primary cause of hospitalization for young military divers during training. The objective of this study was to identify immersion-induced parameters predicting individual susceptibility to IPE. METHODS Eighteen experienced male divers having completed at least 100 dives were recruited. Eight divers had previously been hospitalized for IPE (IPE), and the other ten had never developed IPE (non-IPE). The two groups were matched for age, BMI, and number of dives performed. Ventilatory function and overall compliance of the respiratory system (Crs) were measured on land and during head-out-of-water immersion. Subjects also performed 30 min of fin swimming in a channel at 33 m min-1. Following this exercise, the presence of extravascular lung water, revealed by ultrasound lung comets (ULC), was assessed. RESULTS In the whole group, the decrease in Crs upon immersion correlated with the immersion-induced alterations to expiratory reserve volume, ERV (r2 = 0.91; p < 0.001), inspiratory reserve volume, IRV (r2 = 0.94; p < 0.001), and tidal volume, Vt, changes (r2 = 0.43; p < 0.003). The number of ULC correlated strongly with immersion-induced changes in ventilatory function (r2 = 0.818; p < 0.001 for ERV, r2 = 0.849; p < 0.001 for IRV, r2 = 0.304; p = 0.0164 for Vt) and reduced Crs (r2 = 0.19; p < 0.001). The variations of ERV, IRV, and Crs at rest induced by head-out-of-water immersion and the number of ULC measured after swimming for 30 min were significantly greater in IPE subjects. CONCLUSION In the face of similar immersion stresses, the extent of alterations to ventilatory function and the number of ULCs were very different between individuals but remained statistically correlated. These parameters were significantly greater in divers with a history of IPE. Alterations to pulmonary function and, in particular, to pulmonary compliance induced by head-out-of-water immersion, through their effects on work of breathing appear to allow the identification of divers with a greater susceptibility to developing IPE. Measurement of these parameters could therefore be proposed as a predictive test for the risk of developing IPE.
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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.
| | | | | | - Thibaut Prevautel
- Department of Cardiology, Laveran Military Hospital (HIA Laveran), Marseille, France
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Chen HS, Zhang NN, Cui Y, Li XQ, Zhou CS, Ma YT, Zhang H, Jiang CH, Li RH, Wan LS, Jiao Z, Xiao HB, Li Z, Yan TG, Wang DL, Nguyen TN. A randomized trial of Trendelenburg position for acute moderate ischemic stroke. Nat Commun 2023; 14:2592. [PMID: 37147320 PMCID: PMC10163013 DOI: 10.1038/s41467-023-38313-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2022] [Accepted: 04/25/2023] [Indexed: 05/07/2023] Open
Abstract
We aim to explore the effect of head-down position (HDP), initiated within 24 hours of onset, in moderate anterior circulation stroke patients with probable large artery atherosclerosis (LAA) etiology. This investigator-initiated, multi-center trial prospective, randomized, open-label, blinded-endpoint, multi-center and phase-2 trial was conducted in China and completed in 2021. Eligible patients were randomly assigned (1:1) into the HDP group receiving -20° Trendelenburg, or control group receiving standard care according to national guideline. The primary endpoint was proportion of modified Rankin Scale (mRS) of 0 to 2 at 90 days, which is a scale for measuring the degree of disability after stroke. 90-day mRS was assessed by a certified staff member who was blinded to group assignment. A total of 96 patients were randomized (47 in HDP group and 49 in control group) and 94 (97.9%) patients were included in the final analysis: 46 in HDP group and 48 in control group. The proportion of favorable outcome was 65.2% (30/46) in the HDP group versus 50.0% (24/48) in the control group (unadjusted: OR 2.05 [95%CI 0.87-4.82], P = 0.099). No severe adverse event was attributed to HDP procedures. This work suggests that the head-down position seems safe and feasible, but does not improve favorable functional outcome in acute moderate stroke patients with LAA. This trial was registered with ClinicalTrials.gov, NCT03744533.
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Affiliation(s)
- Hui-Sheng Chen
- Department of Neurology, General Hospital of Northern Theater Command, Shenyang, 110016, China.
| | - Nan-Nan Zhang
- Department of Neurology, General Hospital of Northern Theater Command, Shenyang, 110016, China
| | - Yu Cui
- Department of Neurology, General Hospital of Northern Theater Command, Shenyang, 110016, China
| | - Xiao-Qiu Li
- Department of Neurology, General Hospital of Northern Theater Command, Shenyang, 110016, China
| | - Cheng-Shu Zhou
- Department of Neurology, Anshan Changda Hospital, Anshan, 114000, China
| | - Yu-Tong Ma
- Department of Neurology, Beipiao Central Hospital, Beipiao, 122100, China
| | - Hong Zhang
- Department of Neurology, Fukuang General Hospital of Liaoning Health Industry Group, Fushun, 113005, China
| | - Chang-Hao Jiang
- Department of Neurology, The Traditional Medicine Hospital of Dalian Lvshunkou, Dalian, 116045, China
| | - Run-Hui Li
- Department of Neurology, Central Hospital affiliated to Shenyang Medical College, Shenyang, 110024, China
| | - Li-Shu Wan
- Department of Neurology, Dandong First Hospital, Dandong, 118015, China
| | - Zhen Jiao
- Department of Neurology, Anshan Central Hospital, Anshan, 114000, China
| | - Hong-Bo Xiao
- Department of Neurology, Anshan Central Hospital, Anshan, 114000, China
| | - Zhuo Li
- Department of Neurology, Panjin Central Hospital, Panjin, 124010, China
| | - Ting-Guang Yan
- Department of Neurology, Chaoyang Central Hospital, Chaoyang, 122099, China
| | - Duo-Lao Wang
- Department of Clinical Sciences, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Thanh N Nguyen
- Neurology, Radiology, Boston Medical Center, Boston, MA, USA
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Hélissen O, Kermorgant M, Déjean S, Mercadie A, Le Gonidec S, Zahreddine R, Calise D, Nasr N, Galès C, Arvanitis DN, Pavy-Le Traon A. Autonomic Nervous System Adaptation and Circadian Rhythm Disturbances of the Cardiovascular System in a Ground-Based Murine Model of Spaceflight. Life (Basel) 2023; 13:life13030844. [PMID: 36983999 PMCID: PMC10057816 DOI: 10.3390/life13030844] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 03/16/2023] [Accepted: 03/17/2023] [Indexed: 03/30/2023] Open
Abstract
Whether in real or simulated microgravity, Humans or animals, the kinetics of cardiovascular adaptation and its regulation by the autonomic nervous system (ANS) remain controversial. In this study, we used hindlimb unloading (HU) in 10 conscious mice. Blood pressure (BP), heart rate (HR), temperature, and locomotor activity were continuously monitored with radio-telemetry, during 3 days of control, 5 days of HU, and 2 days of recovery. Six additional mice were used to assess core temperature. ANS activity was indirectly determined by analyzing both heart rate variability (HRV) and baroreflex sensitivity (BRS). Our study showed that HU induced an initial bradycardia, accompanied by an increase in vagal activity markers of HRV and BRS, together with a decrease in water intake, indicating the early adaptation to fluid redistribution. During HU, BRS was reduced; temperature and BP circadian rhythms were altered, showing a loss in day/night differences, a decrease in cycle amplitude, a drop in core body temperature, and an increase in day BP suggestive of a rise in sympathetic activity. Reloading induced resting tachycardia and a decrease in BP, vagal activity, and BRS. In addition to cardiovascular deconditioning, HU induces disruption in day/night rhythmicity of locomotor activity, temperature, and BP.
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Affiliation(s)
- Ophélie Hélissen
- Institute of Cardiovascular and Metabolic Diseases, UMR1297, INSERM, University Hospital of Toulouse, 31400 Toulouse, France
| | - Marc Kermorgant
- Institute of Cardiovascular and Metabolic Diseases, UMR1297, INSERM, University Hospital of Toulouse, 31400 Toulouse, France
- Neurology Department, University Hospital of Toulouse, 31400 Toulouse, France
| | - Sébastien Déjean
- Institut de Mathématiques de Toulouse, UMR5219, CNRS, Université de Toulouse, UT3, 31062 Toulouse, France
| | - Aurélie Mercadie
- Institut de Mathématiques de Toulouse, UMR5219, CNRS, Université de Toulouse, UT3, 31062 Toulouse, France
| | - Sophie Le Gonidec
- CREFRE-Anexplo, Services Phénotypage et Microchirurgie, UMS006, INSERM, Université de Toulouse, UT3, ENVT, 31062 Toulouse, France
| | - Rana Zahreddine
- CREFRE-Anexplo, Services Phénotypage et Microchirurgie, UMS006, INSERM, Université de Toulouse, UT3, ENVT, 31062 Toulouse, France
| | - Denis Calise
- CREFRE-Anexplo, Services Phénotypage et Microchirurgie, UMS006, INSERM, Université de Toulouse, UT3, ENVT, 31062 Toulouse, France
| | - Nathalie Nasr
- Institute of Cardiovascular and Metabolic Diseases, UMR1297, INSERM, University Hospital of Toulouse, 31400 Toulouse, France
| | - Céline Galès
- Institute of Cardiovascular and Metabolic Diseases, UMR1297, INSERM, University Hospital of Toulouse, 31400 Toulouse, France
| | - Dina N Arvanitis
- Institute of Cardiovascular and Metabolic Diseases, UMR1297, INSERM, University Hospital of Toulouse, 31400 Toulouse, France
| | - Anne Pavy-Le Traon
- Institute of Cardiovascular and Metabolic Diseases, UMR1297, INSERM, University Hospital of Toulouse, 31400 Toulouse, France
- Neurology Department, University Hospital of Toulouse, 31400 Toulouse, France
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5
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A century of exercise physiology: key concepts on coupling respiratory oxygen flow to muscle energy demand during exercise. Eur J Appl Physiol 2022; 122:1317-1365. [PMID: 35217911 PMCID: PMC9132876 DOI: 10.1007/s00421-022-04901-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 01/25/2022] [Indexed: 12/26/2022]
Abstract
After a short historical account, and a discussion of Hill and Meyerhof’s theory of the energetics of muscular exercise, we analyse steady-state rest and exercise as the condition wherein coupling of respiration to metabolism is most perfect. The quantitative relationships show that the homeostatic equilibrium, centred around arterial pH of 7.4 and arterial carbon dioxide partial pressure of 40 mmHg, is attained when the ratio of alveolar ventilation to carbon dioxide flow (\documentclass[12pt]{minimal}
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\begin{document}$${\dot{V}}_{A}/{\dot{V}}_{R}{CO}_{2}$$\end{document}V˙A/V˙RCO2) is − 21.6. Several combinations, exploited during exercise, of pertinent respiratory variables are compatible with this equilibrium, allowing adjustment of oxygen flow to oxygen demand without its alteration. During exercise transients, the balance is broken, but the coupling of respiration to metabolism is preserved when, as during moderate exercise, the respiratory system responds faster than the metabolic pathways. At higher exercise intensities, early blood lactate accumulation suggests that the coupling of respiration to metabolism is transiently broken, to be re-established when, at steady state, blood lactate stabilizes at higher levels than resting. In the severe exercise domain, coupling cannot be re-established, so that anaerobic lactic metabolism also contributes to sustain energy demand, lactate concentration goes up and arterial pH falls continuously. The \documentclass[12pt]{minimal}
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\begin{document}$${\dot{V}}_{A}/{\dot{V}}_{R}{CO}_{2}$$\end{document}V˙A/V˙RCO2 decreases below − 21.6, because of ensuing hyperventilation, while lactate keeps being accumulated, so that exercise is rapidly interrupted. The most extreme rupture of the homeostatic equilibrium occurs during breath-holding, because oxygen flow from ambient air to mitochondria is interrupted. No coupling at all is possible between respiration and metabolism in this case.
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Fukuie M, Hoshi D, Hashitomi T, Watanabe K, Tarumi T, Sugawara J. Exercise in Water Provides Better Cardiac Energy Efficiency Than on Land. Front Cardiovasc Med 2021; 8:747841. [PMID: 34966793 PMCID: PMC8710611 DOI: 10.3389/fcvm.2021.747841] [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: 07/26/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Although water-based exercise is one of the most recommended forms of physical activity, little information is available regarding its influence on cardiac workload and myocardial oxygen supply-to-demand. To address this question, we compared subendocardial viability ratio (SEVR, the ratio of myocardial oxygen supply-to-demand), cardiac inotropy (via the maximum rate of aortic pressure rise [dP/dTmax]), and stroke volume (SV, via a Modelflow method) responses between water- and land-based exercise. Eleven healthy men aged 24 ± 1 years underwent mild- to moderate-intensity cycling exercise in water (WC) and on land (LC) consecutively on separate days. In WC, cardiorespiratory variables were monitored during leg cycling exercise (30, 45, and 60 rpm of cadence for 5 min each) using an immersible stationary bicycle. In LC, each participant performed a cycling exercise at the oxygen consumption (VO2) matched to the WC. SEVR and dP/dTmax were obtained by using the pulse wave analysis from peripheral arterial pressure waveforms. With increasing exercise intensity, SEVR exhibited similar progressive reductions in WC (from 211 ± 44 to 75 ± 11%) and LC (from 215 ± 34 to 78 ± 9%) (intensity effect: P < 0.001) without their conditional differences. WC showed higher SV at rest and a smaller increase in SV than LC (environment-intensity interaction: P = 0.009). The main effect of environment on SV was significant (P = 0.002), but that of dP/dTmax was not (P = 0.155). SV was correlated with dP/dTmax (r = 0.717, P < 0.001). When analysis of covariance (ANCOVA) was performed with dP/dTmax as a covariate, the environment effect on SV was still significant (P < 0.001), although environment-intensity interaction was abolished (P = 0.543). These results suggest that water-based exercise does not elicit unfavorable myocardial oxygen supply-to-demand balance at mild-to-moderate intensity compared with land-based exercise. Rather, water-based exercise may achieve higher SV and better myocardial energy efficiency than land-based exercise, even at the same inotropic force.
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Affiliation(s)
- Marina Fukuie
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.,Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Daisuke Hoshi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.,Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Tatsuya Hashitomi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Koichi Watanabe
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takashi Tarumi
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Jun Sugawara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
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7
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Schulz A, Back SN, Schaan VK, Bertsch K, Vögele C. On the construct validity of interoceptive accuracy based on heartbeat counting: Cardiovascular determinants of absolute and tilt-induced change scores. Biol Psychol 2021; 164:108168. [PMID: 34411619 DOI: 10.1016/j.biopsycho.2021.108168] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 08/11/2021] [Accepted: 08/11/2021] [Indexed: 12/18/2022]
Abstract
Interoceptive accuracy (IAcc) as assessed with the heartbeat counting task (IAccHBCT) may be affected by a range of factors including (1.) the ability to adequately detect cardiac signals, indicated by IAcc in a heartbeat discrimination task (IAccHBDT), (2.) cardiac signal properties, affected by sympathetic and parasympathetic tone, and (3.) non-interoceptive processes, including time estimation accuracy (TEAcc). In the current study we investigated the contribution of these factors to absolute and Δ IAccHBCT scores, induced by passive head-up and head-down tilt in 49 healthy individuals. A set of hierarchical regression models showed IAccHBDT scores as the strongest and, across different orthostatic (tilt) conditions, most stable (positive) predictor of absolute and Δ IAccHBCT scores. Neither indicators of cardiac signal properties (except for HR in head-down-tilt), nor TEAcc predicted absolute or Δ IAccHBCT scores. These findings support the convergent and discriminant validity of absolute and Δ IAccHBCT scores.
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Affiliation(s)
- André Schulz
- Clinical Psychophysiology Laboratory, Department of Behavioural and Cognitive Sciences, University of Luxembourg, Esch-sur-Alzette, Luxembourg.
| | - Sarah N Back
- Clinical Psychophysiology Laboratory, Department of Behavioural and Cognitive Sciences, University of Luxembourg, Esch-sur-Alzette, Luxembourg; Division of Clinical Psychology and Psychotherapy, Department of Psychology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Violetta K Schaan
- Clinical Psychophysiology Laboratory, Department of Behavioural and Cognitive Sciences, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | - Katja Bertsch
- Division of Clinical Psychology and Psychotherapy, Department of Psychology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Claus Vögele
- Clinical Psychophysiology Laboratory, Department of Behavioural and Cognitive Sciences, University of Luxembourg, Esch-sur-Alzette, Luxembourg
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8
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Lafère P, Lambrechts K, Germonpré P, Balestra A, Germonpré FL, Marroni A, Cialoni D, Bosco G, Balestra C. Heart Rate Variability During a Standard Dive: A Role for Inspired Oxygen Pressure? Front Physiol 2021; 12:635132. [PMID: 34381372 PMCID: PMC8350129 DOI: 10.3389/fphys.2021.635132] [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: 11/29/2020] [Accepted: 06/18/2021] [Indexed: 01/02/2023] Open
Abstract
Introduction: Heart rate variability (HRV) during underwater diving has been infrequently investigated because of environment limitations and technical challenges. This study aims to analyze HRV changes while diving at variable hyperoxia when using open circuit (OC) air diving apparatus or at constant hyperoxia using a closed-circuit rebreather (CCR). We used HRV analysis in time and frequency domain adding nonlinear analysis which is more adapted to short-time analysis and less dependent on respiratory rate (Sinus respiratory arrhythmia). Materials and Methods: 18 males, 12 using OC (30 mfw for 20 min) and 6 using CCR (30 mfw for 40 min.). HRV was recorded using a polar recorder. Four samples of R-R intervals representing the dive were saved for HRV analysis. Standard deviation of normal-to-normal intervals (SDNN), square root of the mean squared differences between successive RR intervals (rMSSD), and average RR intervals (RR) in time-domain; low frequency (LF) and high frequency (HF) in frequency domain were investigated. Nonlinear analysis included fractal dimension (FrD). Results: SDNN and rMSSD were significantly increased during descent and at depth with OC, not with CCR. Mean RR interval was longer at depth with OC, but only during ascent and after the dive with CCR. HF power was higher than baseline during the descent both with OC and CCR and remained elevated at depth for OC. The LF/HF ratio was significantly lower than baseline for descent and at depth with both OC and CCR. After 30 min of recovery, the LF/HF ratio was higher than baseline with both OC and CCR. Nonlinear analysis detected differences at depth for OC and CCR. Discussion: Increased parasympathetic tone was present during diving. RR duration, SDNN; rMSSD, HF spectral power all increased during the dive above pre-dive levels. Conversely, HF power decreased (and the LF/HF increased) 30 min after the dive. Using FrD, a difference was detected between OC and CCR, which may be related to differences in partial pressure of oxygen breathed during the dive.
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Affiliation(s)
- Pierre Lafère
- Environmental, Occupational & Ageing Physiology Laboratory, Haute Ecole Bruxelles-Brabant, Brussels, Belgium.,DAN Europe Research Division, Roseto degli Abruzzi, Italy.,Laboratoire ORPHY, EA4324, Université de Bretagne Occidentale, Brest, France
| | - Kate Lambrechts
- Environmental, Occupational & Ageing Physiology Laboratory, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - Peter Germonpré
- Environmental, Occupational & Ageing Physiology Laboratory, Haute Ecole Bruxelles-Brabant, Brussels, Belgium.,DAN Europe Research Division, Roseto degli Abruzzi, Italy.,Centre for Hyperbaric Oxygen Therapy, Military Hospital "Queen Astrid", Brussels, Belgium
| | - Ambre Balestra
- Environmental, Occupational & Ageing Physiology Laboratory, Haute Ecole Bruxelles-Brabant, Brussels, Belgium
| | - Faye Lisa Germonpré
- Centre for Hyperbaric Oxygen Therapy, Military Hospital "Queen Astrid", Brussels, Belgium
| | | | - Danilo Cialoni
- DAN Europe Research Division, Roseto degli Abruzzi, Italy.,Environmental Physiology and Medicine Laboratory, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Gerardo Bosco
- Environmental Physiology and Medicine Laboratory, Department of Biomedical Sciences, University of Padova, Padova, Italy
| | - Costantino Balestra
- Environmental, Occupational & Ageing Physiology Laboratory, Haute Ecole Bruxelles-Brabant, Brussels, Belgium.,DAN Europe Research Division, Roseto degli Abruzzi, Italy.,Physical Activity Teaching Unit, Motor Sciences Department, Université Libre de Bruxelles (ULB), Brussels, Belgium
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9
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Broad individual immersion-scattering of respiratory compliance likely substantiates dissimilar breathing mechanics. Sci Rep 2021; 11:9434. [PMID: 33941815 PMCID: PMC8093428 DOI: 10.1038/s41598-021-88925-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 04/19/2021] [Indexed: 11/30/2022] Open
Abstract
Head-out water immersion alters respiratory compliance which underpins defining pressure at a “Lung centroid” and the breathing “Static Lung Load”. In diving medicine as in designing dive-breathing devices a single value of lung centroid pressure is presumed as everyone’s standard. On the contrary, we considered that immersed respiratory compliance is disparate among a homogenous adult group (young, healthy, sporty). We wanted to substantiate this ample scattering for two reasons: (i) it may question the European standard used in designing dive-breathing devices; (ii) it may contribute to understand the diverse individual figures of immersed work of breathing. Resting spirometric measurements of lung volumes and the pressure–volume curve of the respiratory system were assessed for 18 subjects in two body positions (upright Up, and supine Sup). Measurements were taken in air (Air) and with subjects immersed up to the sternal notch (Imm). Compliance of the respiratory system (Crs) was calculated from pressure–volume curves for each condition. A median 60.45% reduction in Crs was recorded between Up-Air and Up-Imm (1.68 vs 0.66 L/kPa), with individual reductions ranging from 16.8 to 82.7%. We hypothesize that the previously disregarded scattering of immersion-reduced respiratory compliance might participate to substantial differences in immersed work of breathing.
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10
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Lundell RV, Tuominen L, Ojanen T, Parkkola K, Räisänen-Sokolowski A. Diving Responses in Experienced Rebreather Divers: Short-Term Heart Rate Variability in Cold Water Diving. Front Physiol 2021; 12:649319. [PMID: 33897457 PMCID: PMC8058382 DOI: 10.3389/fphys.2021.649319] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 03/16/2021] [Indexed: 11/13/2022] Open
Abstract
Introduction Technical diving is very popular in Finland throughout the year despite diving conditions being challenging, especially due to arctic water and poor visibility. Cold water, immersion, submersion, hyperoxia, as well as psychological and physiological stress, all have an effect on the autonomic nervous system (ANS). Materials and methods To evaluate divers' ANS responses, short-term (5 min) heart rate variability (HRV) during dives in 2-4°C water was measured. HRV resting values were evaluated from separate measurements before and after the dives. Twenty-six experienced closed circuit rebreather (CCR) divers performed an identical 45-meter decompression dive with a non-physical task requiring concentration at the bottom depth. Results Activity of the ANS branches was evaluated with the parasympathetic (PNS) and sympathetic (SNS) indexes of the Kubios HRV Standard program. Compared to resting values, PNS activity decreased significantly on immersion with face out of water. From immersion, it increased significantly with facial immersion, just before decompression and just before surfacing. Compared to resting values, SNS activity increased significantly on immersion with face out of water. Face in water and submersion measures did not differ from the immersion measure. After these measurements, SNS activity decreased significantly over time. Conclusion Our study indicates that the trigeminocardiac part of the diving reflex causes the strong initial PNS activation at the beginning of the dive but the reaction seems to decrease quickly. After this initial activation, cold seemed to be the most prominent promoter of PNS activity - not pressure. Also, our study showed a concurrent increase in both SNS and PNS branches, which has been associated with an elevated risk for arrhythmia. Therefore, we recommend a short adaptation phase at the beginning of cold-water diving before physical activity.
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Affiliation(s)
| | - Laura Tuominen
- Department of Anaestesia, Tampere University Hospital, Tampere, Finland
| | - Tommi Ojanen
- Finnish Defence Research Agency, Finnish Defence Forces, Tuusula, Finland
| | - Kai Parkkola
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland.,Department of Leadership and Military Pedagogy, National Defence University, Helsinki, Finland
| | - Anne Räisänen-Sokolowski
- Diving Medical Centre, Finnish Defence Forces, Helsinki, Finland.,Department of Pathology, Helsinki University Hospital, and University of Helsinki, Helsinki, Finland
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11
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Comparison of effect of aquatic interventions on cardiac modulation of obese young males in motion. A crossover trial. BIOMEDICAL HUMAN KINETICS 2021. [DOI: 10.2478/bhk-2021-0003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Abstract
Study aim: The study aimed to compare the effects of passive Watsu therapy and immersion on cardiac locomotor synchronization of obese young males.
Material and methods: Twenty-six volunteer obese males participated in this study (age 18.3 ± 0.32, BMI 36.9 ± 6.52). Heart rate variability parameters were recorded in different positions by the Polar H7 heart rate sensor and HRV+ software. Participants were assigned to two groups, randomly, in a single-blinded crossover design. Kubios HRV 2.2 and MATLAB were used to analyze the bio-signals. Statistical analysis was performed via t-test and ANOVA (analysis of variance) using SPSS. For the significance in results and group comparison, the paired t-test and the independent t-test were used respectively.
Results: Combined results indicated that Watsu therapy increased 3 HRV vertical position parameters and immersion increased 3 HRV non-locomotor parameters, significantly (p < 0.05).
Conclusion: The findings show that Watsu and immersion improved the specific autonomic cardiac modulation. However, non-contact immersion seemed to provide better synchronization of cardiac control and locomotion. The close contact Watsu approach provided improvements in autonomic cardiac regulation. Collectively, these improvements suggest the combination of both therapies in maximizing the cardiac benefits sought by aquatic therapy programs.
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12
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Corbier C, Chouchou F, Roche F, Barthélémy JC, Pichot V. Causal analyses to study autonomic regulation during acute head-out water immersion, head-down tilt and supine position. Exp Physiol 2020; 105:1216-1222. [PMID: 32436624 DOI: 10.1113/ep088640] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 05/18/2020] [Indexed: 11/08/2022]
Abstract
NEW FINDINGS What is the central question of this study? Can Granger causality analysis of R-R intervals, systolic blood pressure and respiration provide evidence for the different physiological mechanisms induced during thermoneutral water immersion, 6 deg head-down tilt and supine position tests that are not accessible using traditional heart rate variability and baroreflex methods? What is the main finding and its importance? The Granger analysis demonstrated a significant difference in the causal link from R-R intervals to respiration between water immersion and head-down tilt. The underlying physiological mechanism explaining this difference could be the variation in peripheral resistances. ABSTRACT Thermoneutral head-out water immersion (WI) and 6 deg head-down tilt (HDT) are used to simulate SCUBA diving, swimming and microgravity, because these models induce an increase in central blood volume. Standard methods to analyse autonomic regulation have demonstrated an increase in parasympathetic activity and baroreflex sensitivity during these experimental conditions. However, such methods are not adapted to quantify all closed-loop interactions involved in respiratory and cardiovascular regulation. To overcome this limitation, we used Granger causality analysis between R-R intervals (RR), systolic blood pressure (SBP) and respiration (RE) in eight young, healthy subjects, recorded during 30 min periods in the supine position, WI and HDT. For all experimental conditions, we found a bidirectional causal relationship between RE and RR and between RR and SBP, with a dominant direction from RR to SBP, and a unidirectional causality from RE to SBP. These causal relationships remained unchanged for the three experimental tests. Interestingly, there was a lower causal relationship from RR to RE during WI compared with HDT. This causal link from RR to RE could be modulated by peripheral resistances. These results highlight differences in cardiovascular regulation during WI and HDT and confirm that Granger causality might reveal physiological mechanisms not accessible with standard methods.
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Affiliation(s)
- Christophe Corbier
- Saint-Etienne Jean Monnet University, Roanne Technology University Institute, University of Lyon, LASPI (EA3059), Roanne, F-42334, France
| | - Florian Chouchou
- University of La Réunion, UFRSHE, IRISSE Laboratory (EA4075), Le Tampon, F-97430, France
| | - Frédéric Roche
- Saint-Etienne Jean Monnet University, CHU de Saint-Etienne, Department of Clinical and Exercise Physiology, University of Lyon, SNA-EPIS (EA4607), Saint-Etienne, F-42055, France
| | - Jean-Claude Barthélémy
- Saint-Etienne Jean Monnet University, CHU de Saint-Etienne, Department of Clinical and Exercise Physiology, University of Lyon, SNA-EPIS (EA4607), Saint-Etienne, F-42055, France
| | - Vincent Pichot
- Saint-Etienne Jean Monnet University, CHU de Saint-Etienne, Department of Clinical and Exercise Physiology, University of Lyon, SNA-EPIS (EA4607), Saint-Etienne, F-42055, France
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