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Robin A, Van Ombergen A, Laurens C, Bergouignan A, Vico L, Linossier MT, Pavy-Le Traon A, Kermorgant M, Chopard A, Py G, Green DA, Tipton M, Choukér A, Denise P, Normand H, Blanc S, Simon C, Rosnet E, Larcher F, Fernandez P, de Glisezinski I, Larrouy D, Harant-Farrugia I, Antunes I, Gauquelin-Koch G, Bareille MP, Billette De Villemeur R, Custaud MA, Navasiolava N. Comprehensive assessment of physiological responses in women during the ESA dry immersion VIVALDI microgravity simulation. Nat Commun 2023; 14:6311. [PMID: 37813884 PMCID: PMC10562467 DOI: 10.1038/s41467-023-41990-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2023] [Accepted: 09/26/2023] [Indexed: 10/11/2023] Open
Abstract
Astronauts in microgravity experience multi-system deconditioning, impacting their inflight efficiency and inducing dysfunctions upon return to Earth gravity. To fill the sex gap of knowledge in the health impact of spaceflights, we simulate microgravity with a 5-day dry immersion in 18 healthy women (ClinicalTrials.gov Identifier: NCT05043974). Here we show that dry immersion rapidly induces a sedentarily-like metabolism shift mimicking the beginning of a metabolic syndrome with a drop in glucose tolerance, an increase in the atherogenic index of plasma, and an impaired lipid profile. Bone remodeling markers suggest a decreased bone formation coupled with an increased bone resorption. Fluid shifts and muscular unloading participate to a marked cardiovascular and sensorimotor deconditioning with decreased orthostatic tolerance, aerobic capacity, and postural balance. Collected datasets provide a comprehensive multi-systemic assessment of dry immersion effects in women and pave the way for future sex-based evaluations of countermeasures.
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Affiliation(s)
- Adrien Robin
- Univ Angers, CRC, CHU Angers, Inserm, CNRS, MITOVASC, Equipe CARME, SFR ICAT, F-49000, Angers, France.
| | | | - Claire Laurens
- Institute of Metabolic and Cardiovascular Diseases, INSERM, Paul Sabatier University, UMR1297, Toulouse, France
| | - Audrey Bergouignan
- Anschutz Health and Wellness Center, Division of Endocrinology, University of Colorado, Aurora, CO, USA
| | - Laurence Vico
- INSERM, University Jean Monnet, Mines Saint-Etienne, U 1059, Saint Etienne, France
| | | | - Anne Pavy-Le Traon
- Department of Neurology, CHU Toulouse and I2MC-INSERM 1297, Toulouse, France
| | - Marc Kermorgant
- Department of Neurology, CHU Toulouse and I2MC-INSERM 1297, Toulouse, France
| | - Angèle Chopard
- DMEM, Montpellier University, INRAE, Montpellier, France
| | - Guillaume Py
- DMEM, Montpellier University, INRAE, Montpellier, France
| | - David Andrew Green
- Centre of Human and Applied Physiological Sciences, King's College London, London, UK
| | - Michael Tipton
- Extreme Environments Laboratory, School of Sport, Health and Exercise Science, University of Portsmouth, Portsmouth, PO1 2EF, UK
| | - Alexander Choukér
- Laboratory of Translational Research Stress and Immunity, Department of Anesthesiology, Hospital of the Ludwig-Maximilians-University (LUM), Munich, Germany
| | - Pierre Denise
- Université de Caen Normandie, Inserm, COMETE U1075, CYCERON, CHU de Caen, F-14000, Caen, France
| | - Hervé Normand
- Université de Caen Normandie, Inserm, COMETE U1075, CYCERON, CHU de Caen, F-14000, Caen, France
| | - Stéphane Blanc
- DEPE-IPHC - Département Ecologie, Physiologie et Ethologie, Strasbourg, France
| | - Chantal Simon
- CarMeN Laboratory, INSERM 1060, INRA 1397, University Claude Bernard Lyon1, Human Nutrition Research Center Rhône-Alpes, Oullins, France
| | - Elisabeth Rosnet
- Faculty of Sport Sciences, Université de Reims Champagne-Ardenne, Reims, France
| | | | - Peter Fernandez
- INSERM, University Jean Monnet, Mines Saint-Etienne, U 1059, Saint Etienne, France
| | - Isabelle de Glisezinski
- Institute of Metabolic and Cardiovascular Diseases, INSERM, Paul Sabatier University, UMR1297, Toulouse, France
| | - Dominique Larrouy
- Institute of Metabolic and Cardiovascular Diseases, INSERM, Paul Sabatier University, UMR1297, Toulouse, France
| | - Isabelle Harant-Farrugia
- Institute of Metabolic and Cardiovascular Diseases, INSERM, Paul Sabatier University, UMR1297, Toulouse, France
| | - Inês Antunes
- Telespazio Belgium S.R.L. for the European Space Agency, Noordwijk, The Netherlands
| | | | | | | | - Marc-Antoine Custaud
- Univ Angers, CRC, CHU Angers, Inserm, CNRS, MITOVASC, Equipe CARME, SFR ICAT, F-49000, Angers, France.
| | - Nastassia Navasiolava
- Univ Angers, CRC, CHU Angers, Inserm, CNRS, MITOVASC, Equipe CARME, SFR ICAT, F-49000, Angers, France.
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Robin A, Wang L, Custaud MA, Liu J, Yuan M, Li Z, Lloret JC, Liu S, Dai X, Zhang J, Lv K, Li W, Gauquelin-Koch G, Wang H, Li K, Li X, Qu L, Navasiolava N, Li Y. Running vs. resistance exercise to counteract deconditioning induced by 90-day head-down bedrest. Front Physiol 2022; 13:902983. [PMID: 36117704 PMCID: PMC9473647 DOI: 10.3389/fphys.2022.902983] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Accepted: 06/29/2022] [Indexed: 11/13/2022] Open
Abstract
Spaceflight is associated with enhanced inactivity, resulting in muscular and cardiovascular deconditioning. Although physical exercise is commonly used as a countermeasure, separate applications of running and resistive exercise modalities have never been directly compared during long-term bedrest. This study aimed to compare the effectiveness of two exercise countermeasure programs, running and resistance training, applied separately, for counteracting cardiovascular deconditioning induced by 90-day head-down bedrest (HDBR). Maximal oxygen uptake (V˙O2max), orthostatic tolerance, continuous ECG and blood pressure (BP), body composition, and leg circumferences were measured in the control group (CON: n = 8), running exercise group (RUN: n = 7), and resistive exercise group (RES: n = 7). After HDBR, the decrease in V˙O2max was prevented by RUN countermeasure and limited by RES countermeasure (−26% in CON p < 0.05, −15% in RES p < 0.05, and −4% in RUN ns). Subjects demonstrated surprisingly modest orthostatic tolerance decrease for different groups, including controls. Lean mass loss was limited by RES and RUN protocols (−10% in CON vs. −5% to 6% in RES and RUN). Both countermeasures prevented the loss in thigh circumference (−7% in CON p < 0.05, −2% in RES ns, and −0.6% in RUN ns) and limited loss in calf circumference (−10% in CON vs. −7% in RES vs. −5% in RUN). Day–night variations in systolic BP were preserved during HDBR. Decrease in V˙O2max positively correlated with decrease in thigh (r = 0.54 and p = 0.009) and calf (r = 0.52 and p = 0.012) circumferences. During this 90-day strict HDBR, running exercise successfully preserved V˙O2max, and resistance exercise limited its decline. Both countermeasures limited loss in global lean mass and leg circumferences. The V˙O2max reduction seems to be conditioned more by muscular than by cardiovascular parameters.
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Affiliation(s)
- Adrien Robin
- Univ Angers, CHU Angers, CRC, INSERM, CNRS, MITOVASC, Equipe CarMe, SFR ICAT, Angers, France
| | - Linjie Wang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Marc-Antoine Custaud
- Univ Angers, CHU Angers, CRC, INSERM, CNRS, MITOVASC, Equipe CarMe, SFR ICAT, Angers, France
| | - Jiexin Liu
- Beijing Tiantan Hospital, Medical Capital University, Beijing, China
| | - Min Yuan
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Zhili Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | | | - Shujuan Liu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Xiaoqian Dai
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Jianfeng Zhang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Ke Lv
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Wenjiong Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | | | - Huijuan Wang
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Kai Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Xiaotao Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Lina Qu
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
| | - Nastassia Navasiolava
- Univ Angers, CHU Angers, CRC, INSERM, CNRS, MITOVASC, Equipe CarMe, SFR ICAT, Angers, France
- *Correspondence: Nastassia Navasiolava, ; Yinghui Li,
| | - Yinghui Li
- State Key Laboratory of Space Medicine Fundamentals and Application, China Astronaut Research and Training Center, Beijing, China
- *Correspondence: Nastassia Navasiolava, ; Yinghui Li,
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Guinet P, MacNamara JP, Berry M, Larcher F, Bareille MP, Custaud MA, Pavy-Le Traon A, Levine BD, Navasiolava N. MNX (Medium Duration Nutrition and Resistance-Vibration Exercise) Bed-Rest: Effect of Resistance Vibration Exercise Alone or Combined With Whey Protein Supplementation on Cardiovascular System in 21-Day Head-Down Bed Rest. Front Physiol 2020; 11:812. [PMID: 32765296 PMCID: PMC7378749 DOI: 10.3389/fphys.2020.00812] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Accepted: 06/18/2020] [Indexed: 12/20/2022] Open
Abstract
Current inflight countermeasures do not completely prevent bone and cardiovascular changes induced by microgravity. High load Resistance Exercise combined with whole body Vibration (RVE) demonstrated benefits on bone and cardiovascular system during previous Head-Down Bed Rest (HDBR) studies. We examined the effectiveness of RVE alone or combined with a nutritional supplementation of Whey protein (NeX) on cardiovascular deconditioning. Eight male subjects (age 34 ± 8 years) in a crossover design completed three 21-day HDBR campaigns (Control-CON, RVE, and NeX). Pre and post HDBR Orthostatic Tolerance (OT) was evaluated by a 15-min head-up tilt test followed by increasing levels of Lower Body Negative Pressure (LBNP). Heart rate (HR), blood pressure (BP), and Sympathetic Index (ΣI) through spectral analysis were measured during OT test. Plasma Volume (PV), and Maximal Oxygen Uptake (VO2max) were measured before and after each campaign. Left ventricular mass, left ventricular end diastolic (LVEDV), end systolic (LVESV), stroke (SV) volumes, and circumferential deformation at rest and during an orthostatic stress simulated by a 30 mmHg LBNP were measured by cardiac MRI. RVE failed to prevent any change in these variables and NeX did not have any additional effect over exercise alone. In the 3 groups, (1) OT time dropped similarly (bed rest p < 0.001), (2) HR and ΣI were increased at rest at the end of HDBR and HR increased markedly during LBNP-tilt test, with inability to increase further the ΣI, (3) PV dropped (bed rest p < 0.001), along with LVEDV, LVESV and SV (p = 0.08, p < 0.001, and p = 0.045, respectively), (4) Left ventricle mass did not change significantly, (5) Deformation of the heart assessed by global circumferential strain was preserved and early diastolic circumferential strain rate was increased during orthostatic stress at the end of HDBR, illustrating preserved systolic and diastolic function respectively, without any difference between groups. Despite the drop in PV and LV volumes, RVE and NeX tended to alleviate the decrease in VO2max. In conclusion, RVE and NeX failed to prevent the cardiovascular deconditioning induced by a 21 day-HDBR.
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Affiliation(s)
- Patrick Guinet
- Département d’Anesthésie Réanimation, Centre Hospitalier Universitaire de Rennes, Rennes, France
- Centre Hospitalier de Fougères, Fougères, France
| | - James Patrick MacNamara
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | | | - Françoise Larcher
- Laboratoire de Biochimie, Centre Hospitalier Universitaire d’Angers, Angers, France
| | | | - Marc-Antoine Custaud
- Centre de Recherche Clinique, Centre Hospitalier Universitaire d’Angers, Angers, France
- Mitovasc UMR INSERM 1083-CNRS 6015, Université d’Angers, Angers, France
| | - Anne Pavy-Le Traon
- Department of Neurology, French Reference Center for MSA, University Hospital of Toulouse, Toulouse, France
- Institute of Cardiovascular and Metabolic Diseases INSERM U 1048, Toulouse, France
| | - Benjamin D. Levine
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital, The University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Nastassia Navasiolava
- Centre de Recherche Clinique, Centre Hospitalier Universitaire d’Angers, Angers, France
- Mitovasc UMR INSERM 1083-CNRS 6015, Université d’Angers, Angers, France
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Kermorgant M, Nasr N, Czosnyka M, Arvanitis DN, Hélissen O, Senard JM, Pavy-Le Traon A. Impacts of Microgravity Analogs to Spaceflight on Cerebral Autoregulation. Front Physiol 2020; 11:778. [PMID: 32719617 PMCID: PMC7350784 DOI: 10.3389/fphys.2020.00778] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Accepted: 06/15/2020] [Indexed: 12/16/2022] Open
Abstract
It is well known that exposure to microgravity in astronauts leads to a plethora physiological responses such as headward fluid shift, body unloading, and cardiovascular deconditioning. When astronauts return to Earth, some encounter problems related to orthostatic intolerance. An impaired cerebral autoregulation (CA), which could be compromised by the effects of microgravity, has been proposed as one of the mechanisms responsible for orthostatic intolerance. CA is a homeostatic mechanism that maintains cerebral blood flow for any variations in cerebral perfusion pressure by adapting the vascular tone and cerebral vessel diameter. The ground-based models of microgravity are useful tools for determining the gravitational impact of spaceflight on human body. The head-down tilt bed rest (HDTBR), where the subject remains in supine position at -6 degrees for periods ranging from few days to several weeks is the most commonly used ground-based model of microgravity for cardiovascular deconditioning. head-down bed rest (HDBR) is able to replicate cephalic fluid shift, immobilization, confinement, and inactivity. Dry immersion (DI) model is another approach where the subject remains immersed in thermoneutral water covered with an elastic waterproof fabric separating the subject from the water. Regarding DI, this analog imitates absence of any supporting structure for the body, centralization of body fluids, immobilization and hypokinesia observed during spaceflight. However, little is known about the impact of microgravity on CA. Here, we review the fundamental principles and the different mechanisms involved in CA. We also consider the different approaches in order to assess CA. Finally, we focus on the effects of short- and long-term spaceflight on CA and compare these findings with two specific analogs to microgravity: HDBR and DI.
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Affiliation(s)
- Marc Kermorgant
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Nathalie Nasr
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Neurology, Institute for Neurosciences, Toulouse University Hospital, Toulouse, France
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge University Hospital, Cambridge, United Kingdom
- Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Dina N. Arvanitis
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Ophélie Hélissen
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Jean-Michel Senard
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Clinical Pharmacology, Toulouse University Hospital, Toulouse, France
| | - Anne Pavy-Le Traon
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Neurology, Institute for Neurosciences, Toulouse University Hospital, Toulouse, France
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Kermorgant M, Nasr N, Custaud MA, Navasiolava N, Arbeille P, Guinet P, Labrunée M, Besnier F, Arvanitis DN, Czosnyka M, Senard JM, Pavy-Le Traon A. Effects of Resistance Exercise and Nutritional Supplementation on Dynamic Cerebral Autoregulation in Head-Down Bed Rest. Front Physiol 2019; 10:1114. [PMID: 31507460 PMCID: PMC6718616 DOI: 10.3389/fphys.2019.01114] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Accepted: 08/12/2019] [Indexed: 11/13/2022] Open
Abstract
Head-down bed rest (HDBR) is commonly considered as ground-based analog to spaceflight and simulates the headward fluid shift and cardiovascular deconditioning associated with spaceflight. We investigated in healthy volunteers whether HDBR, with or without countermeasures, affect cerebral autoregulation (CA). Twelve men (at selection: 34 ± 7 years; 176 ± 7 cm; 70 ± 7 kg) underwent three interventions of a 21-day HDBR: a control condition without countermeasure (CON), a condition with resistance vibration exercise (RVE) comprising of squats, single leg heel, and bilateral heel raises and a condition using also RVE associated with nutritional supplementation (NeX). Cerebral blood flow velocity was assessed using transcranial Doppler ultrasonography. CA was evaluated by transfer function analysis and by the autoregulatory index (Mxa) in order to determine the relationship between mean cerebral blood flow velocity and mean arterial blood pressure. In RVE condition, coherence was increased after HDBR. In CON condition, Mxa index was significantly reduced after HDBR. In contrast, in RVE and NeX conditions, Mxa were increased after HBDR. Our results indicate that HDBR without countermeasures may improve dynamic CA, but this adaptation may be dampened with RVE. Furthermore, nutritional supplementation did not enhance or worsen the negative effects of RVE. These findings should be carefully considered and could not be applied in spaceflight. Indeed, the subjects spent their time in supine position during bed rest, unlike the astronauts who perform normal daily activities.
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Affiliation(s)
- Marc Kermorgant
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Nathalie Nasr
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Neurology, Institute for Neurosciences, Toulouse University Hospital, Toulouse, France
| | - Marc-Antoine Custaud
- MITOVASC Institute, UMR CNRS 6015, UMR INSERM 1083, Clinical Research Centre, University Hospital of Angers, Angers, France
| | - Nastassia Navasiolava
- MITOVASC Institute, UMR CNRS 6015, UMR INSERM 1083, Clinical Research Centre, University Hospital of Angers, Angers, France
| | | | - Patrick Guinet
- Department of Anesthesiology, Thoracic and Cardiovascular Surgery, Rennes University Hospital, Rennes, France
| | - Marc Labrunée
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Rehabilitation, Toulouse University Hospital, Toulouse, France
| | - Florent Besnier
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Dina N. Arvanitis
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
| | - Marek Czosnyka
- Brain Physics Laboratory, Division of Neurosurgery, Department of Clinical Neurosciences, Cambridge University Hospitals, Cambridge, United Kingdom
- Institute of Electronic Systems, Warsaw University of Technology, Warsaw, Poland
| | - Jean-Michel Senard
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Clinical Pharmacology, Toulouse University Hospital, Toulouse, France
| | - Anne Pavy-Le Traon
- INSERM UMR 1048, Institute of Cardiovascular and Metabolic Diseases (I2MC), Toulouse, France
- Department of Neurology, Institute for Neurosciences, Toulouse University Hospital, Toulouse, France
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Laurens C, Simon C, Vernikos J, Gauquelin-Koch G, Blanc S, Bergouignan A. Revisiting the Role of Exercise Countermeasure on the Regulation of Energy Balance During Space Flight. Front Physiol 2019; 10:321. [PMID: 30984019 PMCID: PMC6449861 DOI: 10.3389/fphys.2019.00321] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Accepted: 03/11/2019] [Indexed: 01/24/2023] Open
Abstract
A body mass loss has been consistently observed in astronauts. This loss is of medical concern since energy deficit can exacerbate some of the deleterious physiological changes observed during space flight including cardiovascular deconditioning, bone density, muscle mass and strength losses, impaired exercise capacity, and immune deficiency among others. These may jeopardize crew health and performance, a healthy return to Earth and mission’s overall success. In the context of planning for planetary exploration, achieving energy balance during long-term space flights becomes a research and operational priority. The regulation of energy balance and its components in current longer duration missions in space must be re-examined and fully understood. The purpose of this review is to summarize current understanding of how energy intake, energy expenditure, and hence energy balance are regulated in space compared to Earth. Data obtained in both actual and simulated microgravity thus far suggest that the obligatory exercise countermeasures program, rather than the microgravity per se, may be partly responsible for the chronic weight loss in space. Little is known of the energy intake, expenditure, and balance during the intense extravehicular activities which will become increasingly more frequent and difficult. The study of the impact of exercise on energy balance in space also provides further insights on lifestyle modalities such as intensity and frequency of exercise, metabolism, and the regulation of body weight on Earth, which is currently a topic of animated debate in the field of energy and obesity research. While not dismissing the significance of exercise as a countermeasure during space flight, data now challenge the current exercise countermeasure program promoted and adopted for many years by all the International Space Agencies. An alternative exercise approach that has a minimum impact on total energy expenditure in space, while preventing muscle mass loss and other physiological changes, is needed in order to better understand the in-flight regulation of energy balance and estimate daily energy requirements. A large body of data generated on Earth suggests that alternate approaches, such as high intensity interval training (HIIT), in combination or not with sessions of resistive exercise, might fulfill such needs.
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Affiliation(s)
- Claire Laurens
- Université de Strasbourg, Centre National de la Recherche Scientifique, Institut Pluridisciplinaire Hubert Curien UMR 7178, Strasbourg, France.,Centre National d'Etudes Spatiales, Paris, France
| | - Chantal Simon
- Carmen INSERM U1060, Laboratoire de Recherche en Cardiovasculaire, Métabolisme, Diabétologie et Nutrition, Université de Lyon, Lyon, France.,Human Nutrition Research Centre of Rhône-Alpes, Hospices Civils de Lyon, Lyon, France
| | | | | | - Stéphane Blanc
- Université de Strasbourg, Centre National de la Recherche Scientifique, Institut Pluridisciplinaire Hubert Curien UMR 7178, Strasbourg, France
| | - Audrey Bergouignan
- Université de Strasbourg, Centre National de la Recherche Scientifique, Institut Pluridisciplinaire Hubert Curien UMR 7178, Strasbourg, France.,Anschutz Health and Wellness Center, Anschutz Medical Campus, Aurora, CO, United States.,Division of Endocrinology, Metabolism and Diabetes, University of Colorado, Anschutz Medical Campus, Aurora, CO, United States
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High-Intensity Jump Training Is Tolerated during 60 Days of Bed Rest and Is Very Effective in Preserving Leg Power and Lean Body Mass: An Overview of the Cologne RSL Study. PLoS One 2017; 12:e0169793. [PMID: 28081223 PMCID: PMC5231329 DOI: 10.1371/journal.pone.0169793] [Citation(s) in RCA: 56] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Accepted: 12/21/2016] [Indexed: 12/04/2022] Open
Abstract
Purpose Space agencies are looking for effective and efficient countermeasures for the degrading effects of weightlessness on the human body. The aim of this study was to assess the effects of a novel jump exercise countermeasure during bed rest on vitals, body mass, body composition, and jump performance. Methods 23 male participants (29±6 years, 181±6 cm, 77±7 kg) were confined to a bed rest facility for 90 days: a 15-day ambulatory measurement phase, a 60-day six-degree head-down-tilt bed rest phase (HDT), and a 15-day ambulatory recovery phase. Participants were randomly allocated to the jump training group (JUMP, n = 12) or the control group (CTRL, n = 11). A typical training session consisted of 4x10 countermovement jumps and 2x10 hops in a sledge jump system. The training group had to complete 5–6 sessions per week. Results Peak force for the reactive hops (3.6±0.4 kN) as well as jump height (35±4 cm) and peak power (3.1±0.2 kW) for the countermovement jumps could be maintained over the 60 days of HDT. Lean body mass decreased in CTRL but not in JUMP (-1.6±1.9 kg and 0±1.0 kg, respectively, interaction effect p = 0.03). Resting heart rate during recovery was significantly increased for CTRL but not for JUMP (interaction effect p<0.001). Conclusion Participants tolerated the near-daily high-intensity jump training and maintained high peak forces and high power output during 60 days of bed rest. The countermeasure was effective in preserving lean body mass and partly preventing cardiac deconditioning with only several minutes of training per day.
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Belavý DL, Seibel MJ, Roth HJ, Armbrecht G, Rittweger J, Felsenberg D. The effects of bed-rest and countermeasure exercise on the endocrine system in male adults: evidence for immobilization-induced reduction in sex hormone-binding globulin levels. J Endocrinol Invest 2012; 35:54-62. [PMID: 21422800 DOI: 10.3275/7606] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND AND AIM There is limited data on the effects of inactivity (prolonged bed-rest) on parameters of endocrine and metabolic function; we therefore aimed to examine changes in these systems during and after prolonged (56- day) bed-rest in male adults. SUBJECTS AND METHODS Twenty healthy male subjects underwent 8 weeks of strict bed-rest and 12 months of follow-up as part of the Berlin Bed Rest Study. Subjects were randomized to an inactive group or a group that performed resistive vibration exercise (RVE) during bed-rest. All outcome parameters were measured before, during and after bed-rest. These included body composition (by whole body dual X-ray absorptiometry), SHBG, testosterone (T), estradiol (E2), PRL, cortisol (C), TSH and free T3 (FT3). RESULTS Serum SHBG levels decreased in inactive subjects but remained unchanged in the RVE group (p<0.001). Serum T concentrations increased during the first 3 weeks of bed-rest in both groups (p<0.0001), while E2 levels sharply rose with re-mobilization (p<0.0001). Serum PRL decreased in the control group but increased in the RVE group (p=0.021). C levels did not change over time (p≥0.10). TSH increased whilst FT3 decreased during bed-rest (p all ≤0.0013). CONCLUSIONS Prolonged bed-rest has significant effects on parameters of endocrine and metabolic function, some of which are related to, or counteracted by physical activity.
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Affiliation(s)
- D L Belavý
- Charité University Medical School, Center for Muscle and Bone Research, Berlin, Germany.
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Marrow Fat and Bone: New Insights from Mice and Humans. Clin Rev Bone Miner Metab 2009. [DOI: 10.1007/s12018-009-9050-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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10
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Belavý DL, Miokovic T, Armbrecht G, Richardson CA, Rittweger J, Felsenberg D. Differential atrophy of the lower-limb musculature during prolonged bed-rest. Eur J Appl Physiol 2009; 107:489-99. [DOI: 10.1007/s00421-009-1136-0] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/15/2009] [Indexed: 10/20/2022]
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11
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Trudel G, Payne M, Mädler B, Ramachandran N, Lecompte M, Wade C, Biolo G, Blanc S, Hughson R, Bear L, Uhthoff HK. Bone marrow fat accumulation after 60 days of bed rest persisted 1 year after activities were resumed along with hemopoietic stimulation: the Women International Space Simulation for Exploration study. J Appl Physiol (1985) 2009; 107:540-8. [PMID: 19478189 DOI: 10.1152/japplphysiol.91530.2008] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Immobility in bed and decreased mobility cause adaptations to most human body systems. The effect of immobility on fat accumulation in hemopoietic bone marrow has never been measured prospectively. The reversibility of marrow fat accumulation and the effects on hemopoiesis are not known. In the present study, 24 healthy women (age: 25-40 yr) underwent -6 degrees head-down bed rest for 60 days. We used MRI to noninvasively measure the lumbar vertebral fat fraction at various time points. We also measured hemoglobin, erythropoietin, reticulocytes, leukocytes, platelet count, peripheral fat mass, leptin, cortisol, and C-reactive protein during bed rest and for 1 yr after bed rest ended. Compared with baseline, the mean (+/-SE) fat fraction was increased after 60 days of bed rest (+2.5+/-1.1%, P<0.05); the increase persisted 1 yr after the resumption of regular activities (+2.3+/-0.8%, P<0.05). Mean hemoglobin levels were significantly decreased 6 days after bed rest ended (-1.36+/-0.20 g/dl, P<0.05) but had recovered at 1 yr, with significantly lower mean circulating erythropoietin levels (-3.8+/-1.2 mU/ml, P<0.05). Mean numbers of neutrophils and lymphocytes remained significantly elevated at 1 yr (+617+/-218 neutrophils/microl and +498+/-112 lymphocytes/microl, both P<0.05). These results constitute direct evidence that bed rest irreversibly accelerated fat accumulation in hemopoietic bone marrow. The 2.5% increase in fat fraction after 60 days of bed rest was 25-fold larger than expected from historical ambulatory controls. Sixty days of bed rest accelerated by 4 yr the normal bone marrow involution. Bed rest and marrow adiposity were associated with hemopoietic stimulation. One year after subjects returned to normal activities, hemoglobin levels were maintained, with 43% lower circulating erythropoietin levels, and leukocytes remained significantly elevated across lineages. Lack of mobility alters hemopoiesis, possibly through marrow fat accumulation, with potentially wide-ranging clinical consequences.
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Affiliation(s)
- Guy Trudel
- Bone and Joint Laboratory, University of Ottawa, The Ottawa Hospital Rehabilitation Centre, 505 Smyth Rd., Ottawa, ON, Canada K1H 8M2.
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WISE-2005: effect of aerobic and resistive exercises on orthostatic tolerance during 60 days bed rest in women. Eur J Appl Physiol 2009; 106:217-27. [PMID: 19247686 DOI: 10.1007/s00421-009-1009-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/02/2009] [Indexed: 10/21/2022]
Abstract
Cardiovascular deconditioning after long duration spaceflight is especially challenging in women who have a lower orthostatic tolerance (OT) compared with men. We hypothesized that an exercise prescription, combining supine aerobic treadmill exercise in a lower body negative pressure (LBNP) chamber followed by 10 min of resting LBNP, three to four times a week, and flywheel resistive training every third day would maintain orthostatic tolerance (OT) in women during a 60-day head-down-tilt bed rest (HDBR). Sixteen women were assigned to two groups (exercise, control). Pre and post HDBR OT was assessed with a tilt/LBNP test until presyncope. OT time (mean +/- SE) decreased from 17.5 +/- 1.0 min to 9.1 +/- 1.5 min (-50 +/- 6%) in control group (P < 0.001) and from 19.3 +/- 1.3 min to 13.0 +/- 1.9 min (-35 +/- 7%) in exercise group (P < 0.001), with no significant difference in OT time between the two groups after HDBR (P = 0.13). Nevertheless, compared with controls post HDBR, exercisers had a lower heart rate during supine rest (mean +/- SE, 71 +/- 3 vs. 85 +/- 4, P < 0.01), a slower increase in heart rate and a slower decrease in stroke volume over the course of tilt/LBNP test (P < 0.05). Blood volume (mean +/- SE) decreased in controls (-9 +/- 2%, P < 0.01) but was maintained in exercisers (-4 +/- 3%, P = 0.17).Our results suggest that the combined exercise countermeasure did not significantly improve OT but protected blood volume and cardiovascular response to sub tolerance levels of orthostatic stress.
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Arbeille P, Kerbeci P, Mattar L, Shoemaker JK, Hughson R. Insufficient flow reduction during LBNP in both splanchnic and lower limb areas is associated with orthostatic intolerance after bedrest. Am J Physiol Heart Circ Physiol 2008; 295:H1846-54. [DOI: 10.1152/ajpheart.509.2008] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We quantified the impact of a 60-day head-down tilt bed rest (HDBR) with countermeasures on the arterial response to supine lower body negative pressure (LBNP). Twenty-four women [8 control (Con), 8 exercise + LBNP (Ex-LBNP), and 8 nutrition (Nut) subjects] were studied during LBNP (0 to −45 mmHg) before (pre) and on HDBR day 55 (HDBR-55). Left ventricle diastolic volume (LVDV) and mass, flow velocities in the middle cerebral artery (MCA flow) and femoral artery (femoral flow), portal vein cross-sectional area (portal flow), and lower limb resistance (femoral resistance index) were measured. Muscle sympathetic nerve activity (MSNA) was measured in the fibular nerve. Subjects were identified as finishers or nonfinishers of the 10-min post-HDBR tilt test. At HDBR-55, LVDV, mass, and portal flow were decreased from pre-HDBR ( P < 0.05) in the Con and Nut groups only. During LBNP at HDBR-55, femoral and portal flow decreased less, whereas leg MSNA increased similarly, compared with pre-HDBR in the Con, Nut, and NF groups; 11 of 13 nonfinishers showed smaller LBNP-induced reductions in both femoral and portal flow (less vasoconstriction), whereas 10 of 11 finishers maintained vasoconstriction in either one or both regions. The relative distribution of blood flow in the cerebral versus portal and femoral beds during LBNP [MCA flow/(femoral + portal flow)] increased or reduced <15% from pre-HDBR in 10 of 11 finishers but decreased >15% from pre-HDBR in 11 of 13 nonfinishers. Abnormal vasoconstriction in both the portal and femoral vascular areas was associated with orthostatic intolerance. The vascular deconditioning was partially prevented by Ex-LBNP.
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Pavy-Le Traon A, Heer M, Narici MV, Rittweger J, Vernikos J. From space to Earth: advances in human physiology from 20 years of bed rest studies (1986-2006). Eur J Appl Physiol 2007; 101:143-94. [PMID: 17661073 DOI: 10.1007/s00421-007-0474-z] [Citation(s) in RCA: 375] [Impact Index Per Article: 22.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/13/2007] [Indexed: 01/11/2023]
Abstract
Bed rest studies of the past 20 years are reviewed. Head-down bed rest (HDBR) has proved its usefulness as a reliable simulation model for the most physiological effects of spaceflight. As well as continuing to search for better understanding of the physiological changes induced, these studies focused mostly on identifying effective countermeasures with encouraging but limited success. HDBR is characterised by immobilization, inactivity, confinement and elimination of Gz gravitational stimuli, such as posture change and direction, which affect body sensors and responses. These induce upward fluid shift, unloading the body's upright weight, absence of work against gravity, reduced energy requirements and reduction in overall sensory stimulation. The upward fluid shift by acting on central volume receptors induces a 10-15% reduction in plasma volume which leads to a now well-documented set of cardiovascular changes including changes in cardiac performance and baroreflex sensitivity that are identical to those in space. Calcium excretion is increased from the beginning of bed rest leading to a sustained negative calcium balance. Calcium absorption is reduced. Body weight, muscle mass, muscle strength is reduced, as is the resistance of muscle to insulin. Bone density, stiffness of bones of the lower limbs and spinal cord and bone architecture are altered. Circadian rhythms may shift and are dampened. Ways to improve the process of evaluating countermeasures--exercise (aerobic, resistive, vibration), nutritional and pharmacological--are proposed. Artificial gravity requires systematic evaluation. This review points to clinical applications of BR research revealing the crucial role of gravity to health.
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Affiliation(s)
- A Pavy-Le Traon
- Service D'explorations Fonctionnelles Respiratoires Et d'analyses Physiologiques, Hopital La Cavale Blanche, University Hospital of Brest, 29609, Brest Cedex, France.
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15
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Payne MWC, Uhthoff HK, Trudel G. Anemia of immobility: caused by adipocyte accumulation in bone marrow. Med Hypotheses 2007; 69:778-86. [PMID: 17408874 DOI: 10.1016/j.mehy.2007.01.077] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2006] [Accepted: 01/23/2007] [Indexed: 02/06/2023]
Abstract
Anemia of chronic disease has long been used to classify a non-regenerative, low-grade, chronic, normocytic, normochromic anemia that presents with no obvious etiology. Within this group, some patients have a chronic inflammatory condition that limits erythrocyte generation or access to iron stores. This specific type of anemia has been termed anemia of chronic inflammation. However, a substantial remainder of patients diagnosed with anemia of chronic disease present with no active inflammation. These include many clinical populations with reduced limb loading, such as spinal cord injured patients, astronauts, elderly people with limited mobility and experimental bed-rest subjects. In some populations with decreased mobility, accumulation of fat in the bone marrow has been demonstrated. We hypothesize that adipocyte accumulation in bone marrow both passively and actively impairs erythropoiesis and thus defines a new type of anemia called anemia of immobility. The non-specific umbrella term anemia of chronic disease thus becomes obsolete in favour of either the diagnosis of anemia of immobility or anemia of chronic inflammation according to the distinct mechanism involved.
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Affiliation(s)
- Michael W C Payne
- Department of Medicine, Division of Physical Medicine and Rehabilitation, University of Ottawa, Canada.
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Bergouignan A, Schoeller DA, Normand S, Gauquelin-Koch G, Laville M, Shriver T, Desage M, Maho YL, Ohshima H, Gharib C, Blanc S. Effect of physical inactivity on the oxidation of saturated and monounsaturated dietary Fatty acids: results of a randomized trial. PLOS CLINICAL TRIALS 2006; 1:e27. [PMID: 17016547 PMCID: PMC1584255 DOI: 10.1371/journal.pctr.0010027] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Grants] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Accepted: 08/16/2006] [Indexed: 11/18/2022]
Abstract
OBJECTIVES Changes in the way dietary fat is metabolized can be considered causative in obesity. The role of sedentary behavior in this defect has not been determined. We hypothesized that physical inactivity partitions dietary fats toward storage and that a resistance exercise training program mitigates storage. DESIGN We used bed rest, with randomization to resistance training, as a model of physical inactivity. SETTING The trial took place at the Space Clinic (Toulouse, France). PARTICIPANTS A total of 18 healthy male volunteers, of mean age +/- standard deviation 32.6 +/- 4.0 y and body mass index 23.6 +/- 0.7 kg/m(2), were enrolled. INTERVENTIONS An initial 15 d of baseline data collection were followed by 3 mo of strict bed-rest alone (control group, n = 9) or with the addition of supine resistance exercise training every 3 d (exercise group, n = 9). OUTCOME MEASURES Oxidation of labeled [d(31)]palmitate (the main saturated fatty acid of human diet) and [1-(13)C]oleate (the main monounsaturated fatty acid), body composition, net substrate use, and plasma hormones and metabolites were measured. RESULTS Between-group comparisons showed that exercise training did not affect oxidation of both oleate (mean difference 5.6%; 95% confidence interval [95% CI], -3.3% to 14.5%; p = 0.20) and palmitate (mean difference -0.2%; 95% CI, -4.1% to 3.6%; p = 0.89). Within-group comparisons, however, showed that inactivity changed oxidation of palmitate in the control group by -11.0% (95% CI, -19.0% to -2.9%; p = 0.01) and in the exercise group by -11.3% (95% CI, -18.4% to -4.2%; p = 0.008). In contrast, bed rest did not significantly affect oleate oxidation within groups. In the control group, the mean difference in oleate oxidation was 3.2% (95% CI, -4.2% to 10.5%; p = 0.34) and 6.8% (95% CI, -1.2% to 14.7%; p = 0.08) in the exercise group. CONCLUSIONS Independent of changes in energy balance (intake and/or output), physical inactivity decreased the oxidation of saturated but not monounsaturated dietary fat. The effect is apparently not compensated by resistance exercise training. These results suggest that Mediterranean diets should be recommended in sedentary subjects and recumbent patients.
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Affiliation(s)
- Audrey Bergouignan
- Institut Pluridisciplinaire Hubert Curien, Département d'Ecologie, Physiologie, et Ethologie, Strasbourg, France
| | - Dale A Schoeller
- Department of Nutritional Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Sylvie Normand
- Centre de Recherche en Nutrition Humaine de Lyon, Faculté de Médecine Laennec, Lyon, France
| | | | - Martine Laville
- Centre de Recherche en Nutrition Humaine de Lyon, Faculté de Médecine Laennec, Lyon, France
| | - Timothy Shriver
- Department of Nutritional Sciences, University of Wisconsin–Madison, Madison, Wisconsin, United States of America
| | - Michel Desage
- Centre de Recherche en Nutrition Humaine de Lyon, Faculté de Médecine Laennec, Lyon, France
| | - Yvon Le Maho
- Institut Pluridisciplinaire Hubert Curien, Département d'Ecologie, Physiologie, et Ethologie, Strasbourg, France
| | - Hiroshi Ohshima
- Japan Aerospace Exploration Agency, Tsukuba Space Center, Tsukuba, Ibaraki, Japan
| | - Claude Gharib
- Laboratoire de Physiologie de l'Environnement, Faculté de Médecine Grange Blanche, Lyon, France
| | - Stéphane Blanc
- Institut Pluridisciplinaire Hubert Curien, Département d'Ecologie, Physiologie, et Ethologie, Strasbourg, France
- * To whom correspondence should be addressed. E-mail:
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Capelli C, Antonutto G, Kenfack MA, Cautero M, Lador F, Moia C, Tam E, Ferretti G. Factors determining the time course of $${\dot{V}}\hbox{O}_{2\max}$$ decay during bedrest: implications for $${\dot{V}}\hbox{O}_{2\max}$$ limitation. Eur J Appl Physiol 2006; 98:152-60. [PMID: 16924528 DOI: 10.1007/s00421-006-0252-3] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/08/2006] [Indexed: 10/24/2022]
Abstract
The aim of this study was to characterize the time course of maximal oxygen consumption VO2(max) changes during bedrests longer than 30 days, on the hypothesis that the decrease in VO2(max) tends to asymptote. On a total of 26 subjects who participated in one of three bedrest campaigns without countermeasures, lasting 14, 42 and 90 days, respectively, VO2(max) maximal cardiac output (Qmax) and maximal systemic O2 delivery (QaO2max) were measured. After all periods of HDT, VO2max, Qmax, and QaO2max were significantly lower than before. The VO2max decreased less than qmax after the two shortest bedrests, but its per cent decay was about 10% larger than that of Qmax after 90-day bedrest. The VO2max decrease after 90-day bedrest was larger than after 42- and 14-day bedrests, where it was similar. The Qmax and QaO2max declines after 90-day bedrest was equal to those after 14- and 42-day bedrest. The average daily rates of the VO2max, Qmax, and QaO2max decay during bedrest were less if the bedrest duration were longer, with the exception of that of VO2max in the longest bedrest. The asymptotic VO2max decay demonstrates the possibility that humans could keep working effectively even after an extremely long time in microgravity. Two components in the VO2max decrease were identified, which we postulate were related to cardiovascular deconditioning and to impairment of peripheral gas exchanges due to a possible muscle function deterioration.
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Affiliation(s)
- C Capelli
- Dipartimento di Scienze e Tecnologie Biomediche, School of Medicine, University of Udine, Udine, Italy.
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Capelli C, Antonutto G, Kenfack MA, Cautero M, Lador F, Moia C, Tam E, Ferretti G. Factors determining the time course of $${\dot{V}}\hbox{O}_{2\max}$$ decay during bedrest: implications for $${\dot{V}}\hbox{O}_{2\max}$$ limitation. Eur J Appl Physiol 2006. [DOI: 10.100710.1007/s00421-006-0252-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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Arbeille PP, Besnard SS, Kerbeci PP, Mohty DM. Portal vein cross-sectional area and flow and orthostatic tolerance: a 90-day bed rest study. J Appl Physiol (1985) 2005; 99:1853-7. [PMID: 16227458 DOI: 10.1152/japplphysiol.00331.2005] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The objective of this study was to evaluate the changes in the portal vein cross-sectional area (PV CSA) and flow during a stand test associated with orthostatic intolerance. Eighteen subjects underwent a 90-day head-down tilt (HDT) bed rest at 6°: 9 controls (Con) and 9 with flywheel exercise countermeasures (CM). At post-HDT, nine subjects (5 CM, 4 Con) were tolerant, and nine were intolerant. The PV CSA was measured by echography. We found that at HDT day 85, the PV CSA at rest had increased less in the CM subjects than in the Con (+12 vs. +27% from pre-HDT supine; P < 0.05), whereas it increased similarly in tolerant and intolerant subjects (23 and 16%, respectively). Two days after the HDT, there was a decrease in the PV CSA supine compared with the pre-HDT PV CSA supine that was similar for all groups (Con: −11%, CM: −21%; tolerant: −10%, intolerant: −16%; P < 0.05). The PV CSA decreased significantly less from supine to standing in the Con than in the CM group (−2 vs. −10% compared with the pre-HDT stand test; P < 0.05). The PV CSA also decreased significantly from supine to standing compared with the pre-HDT stand test in the tolerant group but not in the intolerant group (−20 vs. +2%; P < 0.05). From these findings, we conclude the following. 1) Because the portal vein is the only output from the splanchnic vascular area, we suggest that the lower reduction in the PV CSA and flow associated with orthostatic intolerance was related to a lower splanchnic arterial vasoconstriction. 2) The flywheel exercise CM helped to reduce the distention of the splanchnic network at rest and to maintain partially the splanchnic vasoconstriction, but it did not reduce the orthostatic intolerance.
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Affiliation(s)
- Philippe P Arbeille
- Unité Médecine et Physiologie Spatiale, Departement de Médecine Nucléaire et Ultrasons, Centres Hospitaliers Universitaires Trousseau, 37044 Tours, France.
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