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Iftime A, Tofolean IT, Pintilie V, Călinescu O, Busnatu S, Papacocea IR. Differential Functional Changes in Visual Performance during Acute Exposure to Microgravity Analogue and Their Potential Links with Spaceflight-Associated Neuro-Ocular Syndrome. Diagnostics (Basel) 2024; 14:1918. [PMID: 39272703 PMCID: PMC11394298 DOI: 10.3390/diagnostics14171918] [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: 06/17/2024] [Revised: 08/23/2024] [Accepted: 08/28/2024] [Indexed: 09/15/2024] Open
Abstract
BACKGROUND Spaceflight-Associated Neuro-Ocular Syndrome (SANS) is a complex pathology threatening the health of astronauts, with incompletely understood causes and no current specific functional diagnostic or screening test. We investigated the use of the differential performance of the visual system (central vs. perimacular visual function) as a candidate marker of SANS-related pathology in a ground-based microgravity analogue. METHODS We used a simple reaction time (SRT) task to visual stimuli, presented in the central and perimacular field of view, as a measure of the overall performance of the visual function, during acute settings (first 10 min) of vertical, bed rest (BR), -6°, and -15° head-down tilt (HDT) presentations in healthy participants (n = 8). We built dose-response models linking the gravitational component to SRT distribution parameters in the central vs. perimacular areas. RESULTS Acute exposure to microgravity induces detectable changes between SRT distributions in the perimacular vs. central retina (increased mean, standard deviation, and tau component of the ex-Gaussian function) in HDT compared with vertical presentation. CONCLUSIONS Functional testing of the perimacular retina might be beneficial for the earlier detection of SANS-related ailments in addition to regular testing of the central vision. Future diagnostic tests should consider the investigation of the extra-macular areas, particularly towards the optic disc.
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Affiliation(s)
- Adrian Iftime
- Biophysics Department, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Ioana Teodora Tofolean
- Ophthalmology Department, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
- Clinical Emergency Eye Hospital, 010464 Bucharest, Romania
| | - Victor Pintilie
- Biophysics Department, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Octavian Călinescu
- Biophysics Department, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
| | - Stefan Busnatu
- Department of Cardiology, University of Medicine and Pharmacy "Carol Davila", Emergency Hospital "Bagdasar-Arseni", 050474 Bucharest, Romania
- Center for Innovation and eHealth, Carol Davila University of Medicine and Pharmacy, 010451 Bucharest, Romania
| | - Ioana Raluca Papacocea
- Center for Innovation and eHealth, Carol Davila University of Medicine and Pharmacy, 010451 Bucharest, Romania
- Physiology III Department, Carol Davila University of Medicine and Pharmacy, 050474 Bucharest, Romania
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Alessandro C, Sarabadani Tafreshi A, Riener R. Cardiovascular responses to leg-press exercises during head-down tilt. Front Sports Act Living 2024; 6:1396391. [PMID: 39290333 PMCID: PMC11406980 DOI: 10.3389/fspor.2024.1396391] [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: 03/05/2024] [Accepted: 08/12/2024] [Indexed: 09/19/2024] Open
Abstract
Introduction Physical exercise and gravitational load affect the activity of the cardiovascular system. How these factors interact with one another is still poorly understood. Here we investigate how the cardiovascular system responds to leg-press exercise during head-down tilt, a posture that reduces orthostatic stress, limits gravitational pooling, and increases central blood volume. Methods Seventeen healthy participants performed leg-press exercise during head-down tilt at different combinations of resistive force, contraction frequency, and exercise duration (30 and 60 s), leading to different exercise power. Systolic (sBP), diastolic (dBP), mean arterial pressure (MAP), pulse pressure (PP) and heart rate (HR) were measured continuously. Cardiovascular responses were evaluated by comparing the values of these signals during exercise recovery to baseline. Mixed models were used to evaluate the effect of exercise power and of individual exercise parameter on the cardiovascular responses. Results Immediately after the exercise, we observed a clear undershoot in sBP (Δ = -7.78 ± 1.19 mmHg), dBP (Δ = -10.37 ± 0.84 mmHg), and MAP (Δ = -8.85 ± 0.85 mmHg), an overshoot in PP (Δ = 7.93 ± 1.13 mmHg), and elevated values of HR (Δ = 33.5 ± 0.94 bpm) compared to baseline (p < 0.0001). However, all parameters returned to similar baseline values 2 min following the exercise (p > 0.05). The responses of dBP, MAP and HR were significantly modulated by exercise power (correlation coefficients: rdBP = -0.34, rMAP = -0.25, rHR = 0.52, p < 0.001). All signals' responses were modulated by contraction frequency (p < 0.05), increasing the undershoot in sBP (Δ = -1.87 ± 0.98 mmHg), dBP (Δ = -4.85 ± 1.01 and Δ = -3.45 ± 0.98 mmHg for low and high resistive force respectively) and MAP (Δ = -3.31 ± 0.75 mmHg), and increasing the overshoot in PP (Δ = 2.57 ± 1.06 mmHg) as well as the value of HR (Δ = 16.8 ± 2.04 and Δ = 10.8 ± 2.01 bpm for low and high resistive force respectively). Resistive force affected only dBP (Δ = -4.96 ± 1.41 mmHg, p < 0.0001), MAP (Δ = -2.97 ± 1.07 mmHg, p < 0.05) and HR (Δ = 6.81 ± 2.81 bpm, p < 0.0001; Δ = 15.72 ± 2.86 bpm, p < 0.0001; Δ = 15.72 ± 2.86 bpm, p < 0.05, depending on the values of resistive force and contraction frequency), and exercise duration affected only HR (Δ = 9.64 ± 2.01 bpm, p < 0.0001). Conclusion Leg exercises caused only immediate cardiovascular responses, potentially due to facilitated venous return by the head-down tilt position. The modulation of dBP, MAP and HR responses by exercise power and that of all signals by contraction frequency may help optimizing exercise prescription in conditions of limited orthostatic stress.
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Affiliation(s)
- Cristiano Alessandro
- School of Medicine and Surgery, Sport and Exercise Medicine, University of Milano-Bicocca, Milan, Italy
- Sensory-Motor Systems Lab, Department of Health Sciences and Technology, Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
| | - Amirehsan Sarabadani Tafreshi
- Sensory-Motor Systems Lab, Department of Health Sciences and Technology, Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
| | - Robert Riener
- Sensory-Motor Systems Lab, Department of Health Sciences and Technology, Institute of Robotics and Intelligent Systems, ETH Zurich, Zurich, Switzerland
- Spinal Cord Injury Center, Medical Faculty, University of Zurich, Zurich, Switzerland
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Swain P, Caplan N, Hughes L. Blood flow restriction: The acute effects of body tilting and reduced gravity analogues on limb occlusion pressure. Exp Physiol 2024. [PMID: 39153209 DOI: 10.1113/ep091874] [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: 03/11/2024] [Accepted: 07/30/2024] [Indexed: 08/19/2024]
Abstract
Blood flow restriction (BFR) has been identified as a potential countermeasure to mitigate physiological deconditioning during spaceflight. Guidelines recommend that tourniquet pressure be prescribed relative to limb occlusion pressure (LOP); however, it is unclear whether body tilting or reduced gravity analogues influence LOP. We examined LOP at the leg and arm during supine bedrest and bodyweight suspension (BWS) at 6° head-down tilt (HDT), horizontal (0°), and 9.5° head-up tilt (HUT) positions. Twenty-seven adults (age, 26 ± 5 years; height, 1.75 ± 0.08 m; body mass, 73 ± 12 kg) completed all tilts during bedrest. A subgroup (n = 15) additionally completed the tilts during BWS. In each position, LOP was measured twice in the leg and arm using the Delfi Personalized Tourniquet System after 5 min of rest and again after a further 5 min. The LOP at the leg increased significantly from 6° HDT to 9.5° HUT in bedrest and BWS by 9-15 mmHg (Cohen's d = 0.7-1.0). Leg LOP was significantly higher during BWS at horizontal and 9.5° HUT postures relative to the same angles during bedrest by 8 mmHg (Cohen's d = 0.6). Arm LOP remained unchanged between body tilts and analogues. Intraclass correlation coefficients for LOP measurements taken after an initial and subsequent 5 min rest period in all conditions ranged between 0.91-0.95 (leg) and 0.83-0.96 (arm). It is advised that LOP be measured before the application of a vascular occlusion in the same body tilt/setting to which it is applied to minimize discrepancies between the actual and prescribed tourniquet pressure.
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Affiliation(s)
- Patrick Swain
- Aerospace Medicine and Rehabilitation Laboratory, Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Nick Caplan
- Aerospace Medicine and Rehabilitation Laboratory, Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
| | - Luke Hughes
- Aerospace Medicine and Rehabilitation Laboratory, Department of Sport, Exercise and Rehabilitation, Faculty of Health and Life Sciences, Northumbria University, Newcastle upon Tyne, UK
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Mendes Zambetta R, Signini ÉDF, Ocamoto GN, Catai AM, Uliam NR, Santarnecchi E, Russo TL. Effects of weightlessness on the cardiovascular system: a systematic review and meta-analysis. Front Physiol 2024; 15:1438089. [PMID: 39129756 PMCID: PMC11310543 DOI: 10.3389/fphys.2024.1438089] [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: 05/25/2024] [Accepted: 07/02/2024] [Indexed: 08/13/2024] Open
Abstract
Background: The microgravity environment has a direct impact on the cardiovascular system due to the fluid shift and weightlessness that results in cardiac dysfunction, vascular remodeling, and altered Cardiovascular autonomic modulation (CAM), deconditioning and poor performance on space activities, ultimately endangering the health of astronauts. Objective: This study aimed to identify the acute and chronic effects of microgravity and Earth analogues on cardiovascular anatomy and function and CAM. Methods: CINAHL, Cochrane Library, Scopus, Science Direct, PubMed, and Web of Science databases were searched. Outcomes were grouped into cardiovascular anatomic, functional, and autonomic alterations, and vascular remodeling. Studies were categorized as Spaceflight (SF), Chronic Simulation (CS), or Acute Simulation (AS) based on the weightlessness conditions. Meta-analysis was performed for the most frequent outcomes. Weightlessness and control groups were compared. Results: 62 articles were included with a total of 963 participants involved. The meta-analysis showed that heart rate increased in SF [Mean difference (MD) = 3.44; p = 0.01] and in CS (MD = 4.98; p < 0.0001), whereas cardiac output and stroke volume decreased in CS (MD = -0.49; p = 0.03; and MD = -12.95; p < 0.0001, respectively), and systolic arterial pressure decreased in AS (MD = -5.20; p = 0.03). According to the qualitative synthesis, jugular vein cross-sectional area (CSA) and volume were greater in all conditions, and SF had increased carotid artery CSA. Heart rate variability and baroreflex sensitivity, in general, decreased in SF and CS, whereas both increased in AS. Conclusion: This review indicates that weightlessness impairs the health of astronauts during and after spaceflight, similarly to the effects of aging and immobility, potentially increasing the risk of cardiovascular diseases. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier CRD42020215515.
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Affiliation(s)
| | - Étore De Favari Signini
- Physical Therapy Department, Federal University of São Carlos, UFSCar, São Carlos, SP, Brazil
| | - Gabriela Nagai Ocamoto
- Physical Therapy Department, Federal University of São Carlos, UFSCar, São Carlos, SP, Brazil
- Brain4care Inc., São Carlos, SP, Brazil
| | - Aparecida Maria Catai
- Physical Therapy Department, Federal University of São Carlos, UFSCar, São Carlos, SP, Brazil
| | - Nicoly Ribeiro Uliam
- Physical Therapy Department, Federal University of São Carlos, UFSCar, São Carlos, SP, Brazil
| | | | - Thiago Luiz Russo
- Physical Therapy Department, Federal University of São Carlos, UFSCar, São Carlos, SP, Brazil
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Magajevski AS, Távora‐Mehta MZP, Mehta N, Maluf DLS, Silva ECP, Concato L, Ortiz MR, Doubrawa E, Lofrano‐Alves MS. Differential hemodynamic adaptations to tilt test in patients with idiopathic atrial fibrillation. Physiol Rep 2024; 12:e16131. [PMID: 38942728 PMCID: PMC11213645 DOI: 10.14814/phy2.16131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 05/29/2024] [Accepted: 06/20/2024] [Indexed: 06/30/2024] Open
Abstract
The hemodynamic response during the transition from the supine to standing position in idiopathic atrial fibrillation (AF) patients is not completely understood. This study aimed to analyze the hemodynamic changes that occur during the head-up tilt test in idiopathic AF patients. We investigated the hemodynamic changes during the head-up tilt test with impedance cardiography in 40 AF patients (12 with AF rhythm-AFr and 28 with sinus rhythm-AFsr) and 38 non-AF controls. Patients with AFr had attenuated SVI decrease after standing when compared to AFsr and non-AF [ΔSVI in mL/m2: -1.3 (-3.4 to 1.7) vs. -6.4 (-17.3 to -0.1) vs. -11.8 (-18.7 to -8.0), respectively; p < 0.001]. PVRI decreased in AFr but increased in AFsr and non-AF [ΔPVRI in dyne.seg.m2/cm5: -477 (-1148 to 82.5) vs. 131 (-525 to 887) vs. 357 (-29 to 681), respectively; p < 0.01]. Similarly, compared with non-AF patients, AFr patients also had a greater HR and greater CI increase after standing. The haemodynamic response to orthostatic challenge suggests differential adaptations between patients with AF rhythm and those reverted to sinus rhythm or healthy controls. Characterizing the hemodynamic phenotype may be relevant for the individualized treatment of AF patients.
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Affiliation(s)
- Adriano Senter Magajevski
- Post Graduate Program in Internal Medicine, Internal Medicine DepartmentFederal University of ParanaCuritibaParanaBrazil
- Cardiac Electrophysiology Service of ParanaCuritibaParanaBrazil
| | - Maria Zildany P. Távora‐Mehta
- Post Graduate Program in Internal Medicine, Internal Medicine DepartmentFederal University of ParanaCuritibaParanaBrazil
- Cardiac Electrophysiology Service of ParanaCuritibaParanaBrazil
| | - Niraj Mehta
- Post Graduate Program in Internal Medicine, Internal Medicine DepartmentFederal University of ParanaCuritibaParanaBrazil
- Cardiac Electrophysiology Service of ParanaCuritibaParanaBrazil
| | | | | | - Leticia Concato
- Cardiac Electrophysiology Service of ParanaCuritibaParanaBrazil
| | | | | | - Marco Stephan Lofrano‐Alves
- Post Graduate Program in Internal Medicine, Internal Medicine DepartmentFederal University of ParanaCuritibaParanaBrazil
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Hall EA, Whittle RS, Diaz-Artiles A. Ocular perfusion pressure is not reduced in response to lower body negative pressure. NPJ Microgravity 2024; 10:67. [PMID: 38851800 PMCID: PMC11162494 DOI: 10.1038/s41526-024-00404-5] [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: 08/19/2023] [Accepted: 05/16/2024] [Indexed: 06/10/2024] Open
Abstract
Lower body negative pressure (LBNP) has been proposed as a countermeasure to mitigate the cephalad fluid shift occurring during spaceflight, which may be associated with the development of Spaceflight Associated Neuro-ocular Syndrome (SANS). This study quantifies the effect of LBNP on intraocular pressure (IOP), mean arterial pressure at eye level (MAPeye), and ocular perfusion pressure (OPP). Twenty-four subjects (12 male, 12 female) were subjected to graded LBNP in 0° supine and 15° head-down tilt (HDT) postures from 0 mmHg to -50 mmHg in 10 mmHg increments. IOP decreased significantly with LBNP pressure in 0° supine (by 0.7 ± 0.09 mmHg per 10 mmHg LBNP pressure, p < 0.001) and in 15° HDT (by 1.0 ± 0.095 mmHg per 10 mmHg of LBNP pressure, p < 0.001). MAPeye significantly decreased by 0.9 ± 0.4 mmHg per 10 mmHg of LBNP pressure in 0° supine (p = 0.016) but did not significantly change with LBNP in 15° HDT (p = 0.895). OPP did not significantly change with LBNP in 0° supine (p = 0.539) but it significantly increased in 15° HDT at 1.0 ± 0.3 mmHg per 10 mmHg of LBNP pressure (p = 0.010). Sex did not have a significant effect on OPP, MAPeye, or IOP in any condition. In 15° HDT, the reduction in IOP during increasing negative pressure, combined with the relatively constant MAPeye, led to the increase in OPP. Furthermore, results suggest that LBNP, while effective in reducing IOP, is not effective in reducing OPP across all postures investigated.
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Affiliation(s)
- Eric A Hall
- Department of Biomedical Engineering, Texas A&M University, College Station, TX, USA
- School of Engineering Medicine (EnMed), Texas A&M University, Houston, TX, USA
| | - Richard S Whittle
- Department of Mechanical and Aerospace Engineering, University of California Davis, Davis, CA, USA
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, USA
| | - Ana Diaz-Artiles
- Department of Aerospace Engineering, Texas A&M University, College Station, TX, USA.
- Department of Kinesiology and Sport Management, Texas A&M University, College Station, TX, USA.
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Wang Y, Neto OP, Weinrich M, Abbott R, Diaz-Artiles A, Kennedy DM. The effect of inherent and incidental constraints on bimanual force control in simulated Martian gravity. Hum Mov Sci 2024; 95:103199. [PMID: 38518737 DOI: 10.1016/j.humov.2024.103199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 02/23/2024] [Accepted: 03/04/2024] [Indexed: 03/24/2024]
Abstract
The ability to coordinate actions between the limbs is important for many operationally relevant tasks associated with space exploration. A future milestone in space exploration is sending humans to Mars. Therefore, an experiment was designed to examine the influence of inherent and incidental constraints on the stability characteristics associated with the bimanual control of force in simulated Martian gravity. A head-up tilt (HUT)/head-down tilt (HDT) paradigm was used to simulate gravity on Mars (22.3° HUT). Right limb dominant participants (N = 11) were required to rhythmically coordinate patterns of isometric forces in 1:1 in-phase and 1:2 multifrequency patterns by exerting force with their right and left limbs. Lissajous displays were provided to guide task performance. Participants performed 14 twenty-second practice trials at 90° HUT (Earth). Following a 30-min rest period, participants performed 2 test trials for each coordination pattern in both Earth and Mars conditions. Performance during the test trials were compared. Results indicated very effective temporal performance of the goal coordination tasks in both gravity conditions. However, results indicated differences associated with the production of force between Earth and Mars. In general, participants produced less force in simulated Martian gravity than in the Earth condition. In addition, force production was more harmonic in Martian gravity than Earth gravity for both limbs, indicating that less force distortions (adjustments, hesitations, and/or perturbations) occurred in the Mars condition than in the Earth condition. The force coherence analysis indicated significantly higher coherence in the 1:1 task than in the 1:2 task for all force frequency bands, with the highest level of coherence in the 1-4 Hz frequency band for both gravity conditions. High coherence in the 1-4 Hz frequency band is associated with a common neural drive that activates the two arms simultaneously and is consistent with the requirements of the two tasks. The results also support the notion that neural crosstalk stabilizes the performance of the 1:1 in-phase task. In addition, significantly higher coherence in the 8-12 Hz frequency bands were observed for the Earth condition than the Mars condition. Force coherence in the 8-12 Hz bands is associated with the processing of sensorimotor information, suggesting that participants were better at integrating visual, proprioceptive, and/or tactile feedback in Earth than for the Mars condition. Overall, the results indicate less neural interference in Martian gravity; however, participants appear to be more effective at using the Lissajous displays to guide performance under Earth's gravity.
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Affiliation(s)
- Yiyu Wang
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA
| | - Osmar P Neto
- Department of Biomedical Engineering, Anhembi Morumbi University, SP, Brazil
| | - Madison Weinrich
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA
| | - Renee Abbott
- Department of Aerospace Engineering, Texas A&M University, TX, USA
| | - Ana Diaz-Artiles
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA; Department of Aerospace Engineering, Texas A&M University, TX, USA
| | - Deanna M Kennedy
- Department of Kinesiology and Sport Management, Texas A&M University, TX, USA.
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Novak P. Head-down tilt reduces the heart rate in postural tachycardia syndrome in acute setting: a pilot study. Neurol Sci 2024; 45:1719-1723. [PMID: 37919442 DOI: 10.1007/s10072-023-07153-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 10/21/2023] [Indexed: 11/04/2023]
Abstract
BACKGROUND Reduced preload and thoracic blood volume accompany postural tachycardia syndrome (POTS). Head-down tilt (HDT) increases both preload and intrathoracic blood volume. The objective of this study was to assess the safety and efficacy of HDT in POTS in acute settings. METHODS This retrospective study evaluated POTS patients. Analyzed data included heart rate, blood pressure, cerebral blood flow velocity (CBFv) in the middle cerebral artery, and capnography. The baseline supine hemodynamic data were compared with the data obtained at the second minute of the -10° HDT. A linear mixed-effects model was used to assess the effect of HDT on hemodynamic variables. RESULTS The HDT was explored in seven POTS patients and an additional seven POTS patients without HDT served as controls. In the HDT arm, four POTS patients had overlapping diagnoses of myalgic encephalopathy/chronic fatigue syndrome (ME/CFS) and one patient had comorbidity of post-acute sequelae of SARS-CoV-2 infection (PASC). HDT lowered heart rate by 10% and increased end-tidal CO2 by 8%. There was no change in other cardiovascular variables. CONCLUSIONS In the acute setting, HDT is safe. HDT reduces the heart rate presumably by modulating baroreflex by enhancing preload and stroke volume, which in turn increases thoracic blood volume with a net effect of parasympathetic cardiovagal activation and/or sympathetic withdrawal. This pilot study provides a foundation to proceed with longitudinal studies exploring the long-term effect of repetitive HDT in conditions associated with preload failure such as POTS, ME/CSF, and PASC.
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Affiliation(s)
- Peter Novak
- Autonomic Laboratory, Department of Neurology, Brigham and Women's Faulkner Hospital, Harvard Medical School, 1153 Centre Street, Boston, MA, 02130, USA.
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Fois M, Diaz-Artiles A, Zaman SY, Ridolfi L, Scarsoglio S. Linking cerebral hemodynamics and ocular microgravity-induced alterations through an in silico-in vivo head-down tilt framework. NPJ Microgravity 2024; 10:22. [PMID: 38413627 PMCID: PMC10899661 DOI: 10.1038/s41526-024-00366-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 02/15/2024] [Indexed: 02/29/2024] Open
Abstract
Head-down tilt (HDT) has been widely proposed as a terrestrial analog of microgravity and used also to investigate the occurrence of spaceflight-associated neuro-ocular syndrome (SANS), which is currently considered one of the major health risks for human spaceflight. We propose here an in vivo validated numerical framework to simulate the acute ocular-cerebrovascular response to 6° HDT, to explore the etiology and pathophysiology of SANS. The model links cerebral and ocular posture-induced hemodynamics, simulating the response of the main cerebrovascular mechanisms, as well as the relationship between intracranial and intraocular pressure to HDT. Our results from short-term (10 min) 6° HDT show increased hemodynamic pulsatility in the proximal-to-distal/capillary-venous cerebral direction, a marked decrease (-43%) in ocular translaminar pressure, and an increase (+31%) in ocular perfusion pressure, suggesting a plausible explanation of the underlying mechanisms at the onset of ocular globe deformation and edema formation over longer time scales.
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Affiliation(s)
- Matteo Fois
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10129, Italy.
| | - Ana Diaz-Artiles
- Department of Aerospace Engineering, Texas A&M University, 3141 TAMU, College Station, TX, 77843-3141, USA
- Department of Kinesiology and Sport Management, Texas A&M University, 2929 Research Pkwy, College Station, TX, 77845, USA
| | - Syeda Yasmin Zaman
- Department of Aerospace Engineering, Texas A&M University, 3141 TAMU, College Station, TX, 77843-3141, USA
| | - Luca Ridolfi
- Department of Environmental, Land and Infrastructure Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10129, Italy
- PolitoBioMed Lab, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10129, Italy
| | - Stefania Scarsoglio
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10129, Italy
- PolitoBioMed Lab, Politecnico di Torino, Corso Duca degli Abruzzi 24, Turin, 10129, Italy
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Jagtap S, Kumar A, Mahale B, Dixit J, Kalange AE, Kanawade R, Gangal S, Vidyasagar P. Response of cardiac pulse parameters in humans at various inclinations via 360° rotating platform for simulated microgravity perspective. NPJ Microgravity 2023; 9:54. [PMID: 37463938 DOI: 10.1038/s41526-023-00301-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 07/02/2023] [Indexed: 07/20/2023] Open
Abstract
On the Earth, the human body is designed and adapted to function under uniform gravitational acceleration. However, exposure to microgravity or weightlessness as experienced by astronauts in space causes significant alterations in the functioning of the human cardiovascular system. Due to limitations in using real microgravity platforms, researchers opted for various ground-based microgravity analogs including head-down tilt (HDT) at fixed inclination. However, in the present study, an investigation of response of various cardiac parameters and their circulatory adaptation in 18 healthy male subjects was undertaken by using an indigenously developed 360° rotating platform. Cardiac pulse was recorded from 0° to 360° in steps of 30° inclination using piezoelectric pulse sensor (MLT1010) and associated cardiac parameters were analyzed. The results showed significant changes in the pulse shape while an interesting oscillating pattern was observed in associated cardiac parameters when rotated from 0° to 360°. The response of cardiac parameters became normal after returning to supine posture indicating the ability of the cardiovascular system to reversibly adapt to the postural changes. The observed changes in cardiac parameters at an inclination of 270°, in particular, were found to be comparable with spaceflight studies. Based on the obtained results and the proposed extended version of fluid redistribution mechanism, we herewith hypothesize that the rotation of a subject to head down tilt inclination (270°) along with other inclinations could represent a better microgravity analog for understanding the cumulative cardiac response of astronauts in space, particularly for short duration space missions.
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Affiliation(s)
- Sagar Jagtap
- Department of Physics, Haribhai V. Desai College, Pune, MS, 411002, India.
| | - Ajay Kumar
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, MS, 411008, India.
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India.
| | - Bhoopesh Mahale
- Department of Electronics, Savitribai Phule Pune University, Pune, MS, 411007, India
| | - Jyotsana Dixit
- Department of Microbiology, Savitribai Phule Pune University, Pune, MS, 411007, India
| | - Ashok E Kalange
- Department of Physics, Tuljaram Chaturchand College, Baramati, Dist., Pune, 413102, MS, India
| | - Rajesh Kanawade
- Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune, MS, 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad, 201002, India
| | - Shashikala Gangal
- Department of Electronics, Savitribai Phule Pune University, Pune, MS, 411007, India
| | - Pandit Vidyasagar
- Department of Physics, Savitribai Phule Pune University, Pune, MS, 411007, India.
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Whittle RS, Diaz-Artiles A. Gravitational effects on carotid and jugular characteristics in graded head-up and head-down tilt. J Appl Physiol (1985) 2023; 134:217-229. [PMID: 36476158 PMCID: PMC9870583 DOI: 10.1152/japplphysiol.00248.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2022] [Revised: 11/23/2022] [Accepted: 12/06/2022] [Indexed: 12/13/2022] Open
Abstract
Altered gravity affects hemodynamics and blood flow in the neck. At least one incidence of jugular venous thrombosis has been reported in an astronaut on the International Space Station. This investigation explores the impact of changes in the direction of the gravitational vector on the characteristics of the neck arteries and veins. Twelve subjects underwent graded tilt from 45° head-up to 45° head-down in 15° increments in both supine and prone positions. At each angle, the cross-sectional area of the left and right common carotid arteries (ACCA) and internal jugular veins (AIJV) were measured by ultrasound. Internal jugular venous pressure (IJVP) was also measured by compression sonography. Gravitational dose-response curves were generated from experimental data. ACCA did not show any gravitational dependence. Conversely, both AIJV and IJVP increased in a nonlinear fashion with head-down tilt. AIJV was significantly larger on the right side than the left side at all tilt angles. In addition, IJVP was significantly elevated in the prone position compared with the supine position, most likely because of raised intrathoracic pressure while prone. Dose-response curves were compared with existing experimental data from parabolic flight and spaceflight studies, showing good agreement on an acute timescale. The quantification of jugular hemodynamics as a function of changes in the gravitational vector presented here provides a terrestrial model to reference spaceflight-induced changes, contributes to the assessment of the pathogenesis of spaceflight venous thromboembolism events, and informs the development of countermeasures.NEW & NOTEWORTHY Flow stasis and thrombosis have been identified in the jugular vein during spaceflight. We measured the area and pressure of the internal jugular vein and the area of the common carotid artery in graded head-up and head-down tilt. Experimental data are used to generate gravitational dose-response curves for the measured variables, demonstrating that jugular vein area and pressure exhibit a nonlinear response to altered gravity. Gravitational dose-response curves show good agreement with spaceflight and parabolic flight studies.
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Affiliation(s)
- Richard S Whittle
- Department of Aerospace Engineering, Texas A&M University, College Station, Texas
| | - Ana Diaz-Artiles
- Department of Aerospace Engineering, Texas A&M University, College Station, Texas
- Department of Kinesiology & Sport Management, Texas A&M University, College Station, Texas
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Wang H, Gao X, Shi Y, Wu D, Li C, Wang W. Effects of trunk posture on cardiovascular and autonomic nervous systems: A pilot study. Front Physiol 2022; 13:1009806. [PMID: 36330208 PMCID: PMC9623330 DOI: 10.3389/fphys.2022.1009806] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 09/28/2022] [Indexed: 01/28/2024] Open
Abstract
Objective: Although regular and moderate physical activity has been shown to improve the cardiovascular and autonomic nervous systems, little has been done to study the effects of postural changes in the movement on the heart and autonomic nervous system. To uncover changes in cardiac function and autonomic nerves induced by different underlying posture transitions and explore which trunk postures lead to chronic sympathetic activation. Therefore, this study investigated the effects of trunk posture on the cardiovascular and autonomic nervous systems. Methods: Twelve male subjects (age 24.7 ± 1.3) underwent this study. The non-invasive cardiac output NICOM monitoring equipment and the FIRSTBEAT system are used to dynamically monitor seven trunk postures in the sitting position simultaneously (neutral position, posterior extension, forward flexion, left lateral flexion, right lateral flexion, left rotation, right rotation). Each posture was maintained for 3 min, and the interval between each movement was 3 min to ensure that each index returned to the baseline level. Repeated analysis of variance test was used to compare and analyze the differences in human cardiac function, heart rate variability index, and respiratory rate under different postures. Results: Compared with the related indicators of cardiac output in a neutral trunk position: the cardiac index (CI) was significantly reduced in forwarding flexion and left rotation (3.48 ± 0.34 vs. 3.21 ± 0.50; 3.48 ± 0.34 vs. 3.21 ± 0.46, Δ L/(min/m2)) (p = 0.016, p = 0.013), cardiac output decreased significantly (6.49 ± 0.78 vs. 5.93 ± 0.90; 6.49 ± 0.78 vs. 6.00 ± 0.96, Δ L/min) (p = 0.006, p = 0.014), the stroke volume (stroke volume)decreased significantly (87.90 ± 15.10 vs. 81.04 ± 16.35; 87.90 ± 15.10 vs. 79.24 ± 16.83, Δ ml/beat) (p = 0.017, p = 0.0003); heart rate increased significantly in posterior extension (75.08 ± 10.43 vs. 78.42 ± 10.18, Δ beat/min) (p = 0.001); left rotation stroke volume index (SVI) decreased significantly (47.28 ± 7.97 vs. 46.14 ± 8.06, Δ ml/m2) (p = 0.0003); in the analysis of HRV-related indicators, compared with the neutral trunk position, the LF/HF of the posterior extension was significantly increased (1.90 ± 1.38 vs. 3.00 ± 1.17, p = 0.037), and the LF/HF of the forward flexion was significantly increased (1.90 ± 1.38 vs. 2.85 ± 1.41, p = 0.041), and the frequency-domain index LF/HF of right rotation was significantly increased (1.90 ± 1.38 vs. 4.06 ± 2.19, p = 0.008). There was no significant difference in respiratory rate (p > 0.05). Conclusion: A neutral trunk is the best resting position, and deviations from a neutral trunk position can affect the cardiovascular and autonomic nervous systems, resulting in decreased stroke volume, increased heart rate, and relative activation of sympathetic tone.
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Affiliation(s)
- Hao Wang
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing, China
| | - Xiaolin Gao
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing, China
| | - Yongjin Shi
- Department of Sports and Arts, China Agricultural University, Beijing, China
| | - Dongzhe Wu
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing, China
| | - Chuangtao Li
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing, China
| | - Wendi Wang
- Sports Rehabilitation Research Center, China Institute of Sport Science, Beijing, China
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Dorogovtsev VN, Yankevich DS, Petrova MV, Torshin VI, Severin AE, Borisov IV, Podolskaya JA, Grechko AV. Detection of Preclinical Orthostatic Disorders in Young African and European Adults Using the Head-Up Tilt Test with a Standardized Hydrostatic Column Height: A Pilot Study. Biomedicines 2022; 10:biomedicines10092156. [PMID: 36140257 PMCID: PMC9496141 DOI: 10.3390/biomedicines10092156] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 08/29/2022] [Accepted: 08/29/2022] [Indexed: 11/16/2022] Open
Abstract
Arterial hypertension (AH) remains the most common disease. One possible way to improve the effectiveness of the primary prevention of AH is to identify and control the preclinical orthostatic disturbances that precede the development of AH. The aim of the study was to determine the feasibility of a new protocol for the head-up tilt test (HUTT) with a standardized hydrostatic column height for the detection of asymptomatic orthostatic circulatory disorders and their racial differences in young African and European adults. Methods. In total, 80 young healthy adults (40 African and 40 European) aged 20–23 years performed the HUTT with a standardized hydrostatic column height of 133 cm. The hemodynamic parameters were recorded using a Task Force Monitor (3040i). The cardio-ankle vascular index (CAVI) was measured using a VaSera VS-2000 volumetric sphygmograph. Results. The baseline and orthostatic hemodynamic changes in both racial groups were within normal limits. Orthostatic circulatory disturbances were not detected in 70% of the European participants and 65% of the African participants; however, preclinical orthostatic hypertension, which precedes AH, was detected using the new HUTT protocol in 32.5% of the African participants and 20% of the European participants. The baseline CAVI was higher in the European group compared to the African group. Conclusion. The results of this study showed the feasibility of the detection of preclinical orthostatic disturbances in young adults and the detection of their racial differences using the HUTT protocol, providing the use of a standard gravity load. Further study on the evolution of preclinical orthostatic disturbances and their relation to increased vascular stiffness is necessary among large samples.
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Affiliation(s)
- Victor N. Dorogovtsev
- Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia
- Correspondence:
| | - Dmitry S. Yankevich
- Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia
| | - Marina V. Petrova
- Department of Anesthesiology and Resuscitation with Medical Rehabilitation Courses, Peoples’ Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198 Moscow, Russia
| | - Vladimir I. Torshin
- Department of Normal Physiology, and Department of Anesthesiology and Resuscitation with Medical Rehabilitation Courses, Peoples’ Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198 Moscow, Russia
| | - Aleksander E. Severin
- Department of Normal Physiology, and Department of Anesthesiology and Resuscitation with Medical Rehabilitation Courses, Peoples’ Friendship University of Russia (RUDN University), 6 Miklukho-Maklaya Street, 117198 Moscow, Russia
| | - Ilya V. Borisov
- Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia
| | - Julia A. Podolskaya
- Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia
| | - Andrey V. Grechko
- Federal Research and Clinical Center of Intensive Care Medicine and Rehabilitology, 107031 Moscow, Russia
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