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Lanéelle D, Ogoh S, Trihan JE, Bailey DM, Normand H. Selective elevation in external carotid artery flow during acute gravitational transition to microgravity during parabolic flight. Am J Physiol Heart Circ Physiol 2023; 325:H665-H672. [PMID: 37565259 DOI: 10.1152/ajpheart.00341.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 07/19/2023] [Accepted: 08/03/2023] [Indexed: 08/12/2023]
Abstract
This study sought to determine to what extent acute exposure to microgravity (0 G) and related increases in central blood volume (CBV) during parabolic flight influence the regional redistribution of intra and extra cranial cerebral blood flow (CBF). Eleven healthy participants performed during two parabolic flights campaigns aboard the Airbus A310-ZERO G aircraft. The response of select variables for each of the 15 parabolas involving exposure to both 0 G and hypergravity (1.8 G) were assessed in the seated position. Mean arterial blood pressure (MAP) and heart rate (HR) were continuously monitored and used to calculate stroke volume (SV), cardiac output ([Formula: see text]), and systemic vascular resistance (SVR). Changes in CBV were measured using an impedance monitor. Extracranial flow through the internal carotid, external carotid, and vertebral artery ([Formula: see text]ICA, [Formula: see text]ECA, and [Formula: see text]VA), and intracranial blood velocity was measured by duplex ultrasound. When compared with 1-G baseline condition, 0 G increased CBV (+375 ± 98 mL, P = 0.004) and [Formula: see text] (+16 ± 14%, P = 0.024) and decreased SVR (-7.3 ± 5 mmHg·min·L-1, P = 0.002) and MAP (-13 ± 4 mmHg, P = 0.001). [Formula: see text]ECA increased by 43 ± 46% in 0 G (P = 0.030), whereas no change was observed for CBF, [Formula: see text]ICA, or [Formula: see text]VA (P = 0.102, P = 0.637, and P = 0.095, respectively).NEW & NOTEWORTHY Our findings demonstrate that in microgravity there is a selective increase in external carotid artery blood flow whereas global and regional cerebral blood flow remained preserved. To what extent this reflects an adaptive, neuroprotective response to counter overperfusion remains to be established.
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Affiliation(s)
- Damien Lanéelle
- INSERM UMRS-1075, COMETE, GIP Cyceron, University of Caen Normandy, Caen, France
- Department of Vascular Medicine, University Hospital of Caen Normandy, Caen, France
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | | | - Damian M Bailey
- Neurovascular Research Laboratory, Faculty of Life Sciences and Education, University of South Wales, Glamorgan, United Kingdom
| | - Hervé Normand
- INSERM UMRS-1075, COMETE, GIP Cyceron, University of Caen Normandy, Caen, France
- Department of Clinical Physiology, University Hospital of Caen Normandy, Caen, France
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2
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Sugawara J, Hashimoto T, Tsukamoto H, Secher NH, Ogoh S. Attenuated pulsatile transition to the cerebral vasculature during high-intensity interval exercise in young healthy men. Exp Physiol 2023; 108:1057-1065. [PMID: 37309084 PMCID: PMC10988493 DOI: 10.1113/ep091119] [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: 01/04/2023] [Accepted: 05/15/2023] [Indexed: 06/14/2023]
Abstract
NEW FINDINGS What is the central question of this study? High-intensity interval exercise (HIIE) is recommended for its favourable haemodynamic stimulation, but excessive haemodynamic fluctuations may stress the brain: is the cerebral vasculature protected against exaggerated systemic blood flow fluctuation during HIIE? What is the main finding and its importance? Time- and frequency-domain indices of aortic-cerebral pulsatile transition were lowered during HIIE. The findings suggest that the arterial system to the cerebral vasculature may attenuate pulsatile transition during HIIE as a defence mechanism against pulsatile fluctuation for the cerebral vasculature. ABSTRACT High-intensity interval exercise (HIIE) is recommended because it provides favourable haemodynamic stimulation, but excessive haemodynamic fluctuations may be an adverse impact on the brain. We tested whether the cerebral vasculature is protected against systemic blood flow fluctuation during HIIE. Fourteen healthy men (age 24 ± 2 years) underwent four 4-min exercises at 80-90% of maximal workload (Wmax ) interspaced by 3-min active rest at 50-60% Wmax . Transcranial Doppler measured middle cerebral artery blood velocity (CBV). Systemic haemodynamics (Modelflow) and aortic pressure (AoP, general transfer function) were estimated from an invasively recorded brachial arterial pressure waveform. Using transfer function analysis, gain and phase between AoP and CBV (0.39-10.0 Hz) were calculated. Stroke volume, aortic pulse pressure and pulsatile CBV increased during exercise (time effect: P < 0.0001 for all), but a time-domain index of aortic-cerebral pulsatile transition (pulsatile CBV/pulsatile AoP) decreased throughout the exercise bouts (time effect: P < 0.0001). Furthermore, transfer function gain reduced, and phase increased throughout the exercise bouts (time effect: P < 0.0001 for both), suggesting the attenuation and delay of pulsatile transition. The cerebral vascular conductance index (mean CBV/mean arterial pressure; time effect: P = 0.296), an inverse index of cerebral vascular tone, did not change even though systemic vascular conductance increased during exercise (time effect: P < 0.0001). The arterial system to the cerebral vasculature may attenuate pulsatile transition during HIIE as a defence mechanism against pulsatile fluctuation for the cerebral vasculature.
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Affiliation(s)
- Jun Sugawara
- Human Informatics and Interaction Research InstituteNational Institute of Advanced Industrial Science and TechnologyTsukubaJapan
| | - Takeshi Hashimoto
- Graduate School of Sport and Health ScienceRitsumeikan UniversityShigaJapan
| | | | - Niels H. Secher
- Department of Anesthesia, Rigshospitalet, Institute for Clinical MedicineUniversity of CopenhagenDenmark
| | - Shigehiko Ogoh
- Graduate School of EngineeringToyo UniversitySaitamaJapan
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3
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Mankoo A, Roy S, Davies A, Panerai RB, Robinson TG, Brassard P, Beishon LC, Minhas JS. The role of the autonomic nervous system in cerebral blood flow regulation in stroke: A review. Auton Neurosci 2023; 246:103082. [PMID: 36870192 DOI: 10.1016/j.autneu.2023.103082] [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: 12/24/2021] [Revised: 11/22/2022] [Accepted: 02/22/2023] [Indexed: 03/02/2023]
Abstract
Stroke is a pathophysiological condition which results in alterations in cerebral blood flow (CBF). The mechanism by which the brain maintains adequate CBF in presence of fluctuating cerebral perfusion pressure (CPP) is known as cerebral autoregulation (CA). Disturbances in CA may be influenced by a number of physiological pathways including the autonomic nervous system (ANS). The cerebrovascular system is innervated by adrenergic and cholinergic nerve fibers. The role of the ANS in regulating CBF is widely disputed owing to several factors including the complexity of the ANS and cerebrovascular interactions, limitations to measurements, variation in methods to assess the ANS in relation to CBF as well as experimental approaches that can or cannot provide insight into the sympathetic control of CBF. CA is known to be impaired in stroke however the number of studies investigating the mechanisms by which this occurs are limited. This literature review will focus on highlighting the assessment of the ANS and CBF via indices derived from the analyses of heart rate variability (HRV), and baroreflex sensitivity (BRS), and providing a summary of both clinical and animal model studies investigating the role of the ANS in influencing CA in stroke. Understanding the mechanisms by which the ANS influences CBF in stroke patients may provide the foundation for novel therapeutic approaches to improve functional outcomes in stroke patients.
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Affiliation(s)
- Alex Mankoo
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom
| | - Sankanika Roy
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom.
| | - Aaron Davies
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom
| | - Ronney B Panerai
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Thompson G Robinson
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Université Laval, Québec, QC, Canada; Research center of the Institut universitaire de cardiologie et de pneumologie de Québec-Université Laval, Québec, QC, Canada
| | - Lucy C Beishon
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom
| | - Jatinder S Minhas
- University of Leicester, Department of Cardiovascular Sciences, Leicester, United Kingdom; NIHR Leicester Biomedical Research Centre, British Heart Foundation Cardiovascular Research Centre, Glenfield Hospital, Leicester, United Kingdom
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4
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Saehle T. Cerebral Hemodynamics During Exposure to Hypergravity (+G z) or Microgravity (0 G). Aerosp Med Hum Perform 2022; 93:581-592. [DOI: 10.3357/amhp.6008.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND: Optimal human performance and health is dependent on steady blood supply to the brain. Hypergravity (+Gz) may impair cerebral blood flow (CBF), and several investigators have also reported that microgravity (0 G) may influence cerebral hemodynamics. This
has led to concerns for safe performance during acceleration maneuvers in aviation or the impact long-duration spaceflights may have on astronaut health.METHODS: A systematic PEO (Population, Exposure, Outcome) search was done in PubMed and Web of Science, addressing studies on
how elevated +Gz forces or absence of such may impact cerebral hemodynamics. All primary research containing anatomical or physiological data on relevant intracranial parameters were included. Quality of the evidence was analyzed using the GRADE tool.RESULTS: The search
revealed 92 eligible articles. It is evident that impaired CBF during +Gz acceleration remains an important challenge in aviation, but there are significant variations in individual tolerance. The reports on cerebral hemodynamics during weightlessness are inconsistent, but published
data indicate that adaptation to sustained microgravity is also characterized by significant variations among individuals.DISCUSSION: Despite a high number of publications, the quality of evidence is limited due to observational study design, too few included subjects, and methodological
challenges. Clinical consequences of high +Gz exposure are well described, but there are significant gaps in knowledge regarding the intracranial pathophysiology and individual hemodynamic tolerance to both hypergravity and microgravity environments.Saehle T. Cerebral
hemodynamics during exposure to hypergravity (+Gz) or microgravity (0 G). Aerosp Med Hum Perform. 2022; 93(7):581–592.
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5
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Saito S, Washio T, Watanabe H, Katayama K, Ogoh S. Influence of cardiac output response to the onset of exercise on cerebral blood flow. Eur J Appl Physiol 2022; 122:1939-1948. [PMID: 35660969 DOI: 10.1007/s00421-022-04973-9] [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: 11/17/2021] [Accepted: 05/18/2022] [Indexed: 11/03/2022]
Abstract
PURPOSE Change in cardiac output (Q) contributes to cerebral blood flow (CBF) regulation at rest and even during steady-state exercise. At the onset of cycling exercise, Q increases acutely and largely via muscle pump. The purpose of the present study was to examine whether onset exercise-induced a large increase in Q contributes to CBF regulation at the onset of exercise. METHODS In 20 young healthy participants (10 males and 10 females), Q, mean arterial pressure (MAP), and mean blood velocities of middle and posterior cerebral arteries (MCA Vm and PCA Vm) were continuously measured during light cycling exercise for 3 min. RESULTS At the onset of exercise, Q increased acutely to the peak (P < 0.001), while the CBF peak responses were not significantly higher than the values during the steady-state exercise (MCA Vm and PCA Vm; P = 0.183 and P = 0.101, respectively). The change in Q was correlated with that of MCA Vm or PCA Vm from resting baseline to the steady-state exercise (r = 0.404, P < 0.001 and r = 0.393, P < 0.001, respectively). However, the change in Q was not correlated with that of MCA Vm or PCA Vm at the onset of exercise (P = 0.853 and P = 0.893, respectively). Any sex differences in the onset response of peripheral and cerebral hemodynamics to exercise were not observed. CONCLUSION These findings suggest that the acute change in Q does not contribute to CBF regulation at the onset of exercise for protecting cerebral vasculature against a large and acute elevation in Q at the onset of exercise.
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Affiliation(s)
- Shotaro Saito
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Keisho Katayama
- Research Center of Health, Physical Fitness, and Sports, Graduate School of Medicine, Nagoya University, Nagoya, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan. .,Neurovascular Research Laboratory, University of South Wales, Pontypridd, UK.
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6
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Jirak P, Mirna M, Rezar R, Motloch LJ, Lichtenauer M, Jordan J, Binneboessel S, Tank J, Limper U, Jung C. How spaceflight challenges human cardiovascular health. Eur J Prev Cardiol 2022; 29:1399-1411. [PMID: 35148376 DOI: 10.1093/eurjpc/zwac029] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 01/08/2022] [Accepted: 02/06/2022] [Indexed: 11/14/2022]
Abstract
The harsh environmental conditions in space, particularly weightlessness and radiation exposure, can negatively affect cardiovascular function and structure. In the future, preventive cardiology will be crucial in enabling safe space travel. Indeed, future space missions destined to the Moon and from there to Mars will create new challenges to cardiovascular health while limiting medical management. Moreover, commercial spaceflight evolves rapidly such that older persons with cardiovascular risk factors will be exposed to space conditions. This review provides an overview on studies conducted in space and in terrestrial models, particularly head-down bedrest studies. These studies showed that weightlessness elicits a fluid shift towards the head, which likely predisposes to the spaceflight-associated neuro-ocular syndrome, neck vein thrombosis, and orthostatic intolerance after return to Earth. Moreover, cardiovascular unloading produces cardiopulmonary deconditioning which may be associated with cardiac atrophy. In addition to limiting physical performance, the mechanism further worsens orthostatic tolerance after return to Earth. Finally, space conditions may directly affect vascular health, however, the clinical relevance of these findings in terms of morbidity and mortality is unknown. Targeted preventive measures, which are referred to as countermeasures in aerospace medicine, and technologies to identify vascular risks early on will be required to maintain cardiovascular performance and health during future space missions.
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Affiliation(s)
- Peter Jirak
- Clinic II for Internal Medicine, University Hospital Salzburg, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Moritz Mirna
- Clinic II for Internal Medicine, University Hospital Salzburg, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Richard Rezar
- Clinic II for Internal Medicine, University Hospital Salzburg, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Lukas J Motloch
- Clinic II for Internal Medicine, University Hospital Salzburg, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Michael Lichtenauer
- Clinic II for Internal Medicine, University Hospital Salzburg, Paracelsus Medical University, 5020 Salzburg, Austria
| | - Jens Jordan
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany.,Medical Faculty, University of Cologne, Germany
| | - Stephan Binneboessel
- Division of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, University Duesseldorf, Germany
| | - Jens Tank
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany
| | - Ulrich Limper
- Institute of Aerospace Medicine, German Aerospace Center, Cologne, Germany.,Department of Anaesthesiology and Critical Care Medicine, Merheim Medical Center, Witten/Herdecke University, Cologne, Germany
| | - Christian Jung
- Division of Cardiology, Pulmonology, and Vascular Medicine, Medical Faculty, University Duesseldorf, Germany
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7
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Ogoh S, Saito S, Watanabe H, Katayama K. Cerebral blood velocity and arterial pressure at the onset of exercise: potential influence of the cardiopulmonary baroreflex. Clin Auton Res 2022; 32:143-146. [PMID: 35129712 DOI: 10.1007/s10286-022-00855-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 02/01/2022] [Indexed: 11/27/2022]
Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan.
- Neurovascular Research Laboratory, University of South Wales, Pontypridd, UK.
| | - Shotaro Saito
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Hironori Watanabe
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe-shi, Saitama, 350-8585, Japan
| | - Keisho Katayama
- Physical Fitness, and Sports, Graduate School of Medicine, Research Center of Health, Nagoya University, Nagoya, Japan
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8
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Fukuie M, Hoshi D, Hashitomi T, Watanabe K, Tarumi T, Sugawara J. Exercise in Water Provides Better Cardiac Energy Efficiency Than on Land. Front Cardiovasc Med 2021; 8:747841. [PMID: 34966793 PMCID: PMC8710611 DOI: 10.3389/fcvm.2021.747841] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 11/08/2021] [Indexed: 11/13/2022] Open
Abstract
Although water-based exercise is one of the most recommended forms of physical activity, little information is available regarding its influence on cardiac workload and myocardial oxygen supply-to-demand. To address this question, we compared subendocardial viability ratio (SEVR, the ratio of myocardial oxygen supply-to-demand), cardiac inotropy (via the maximum rate of aortic pressure rise [dP/dTmax]), and stroke volume (SV, via a Modelflow method) responses between water- and land-based exercise. Eleven healthy men aged 24 ± 1 years underwent mild- to moderate-intensity cycling exercise in water (WC) and on land (LC) consecutively on separate days. In WC, cardiorespiratory variables were monitored during leg cycling exercise (30, 45, and 60 rpm of cadence for 5 min each) using an immersible stationary bicycle. In LC, each participant performed a cycling exercise at the oxygen consumption (VO2) matched to the WC. SEVR and dP/dTmax were obtained by using the pulse wave analysis from peripheral arterial pressure waveforms. With increasing exercise intensity, SEVR exhibited similar progressive reductions in WC (from 211 ± 44 to 75 ± 11%) and LC (from 215 ± 34 to 78 ± 9%) (intensity effect: P < 0.001) without their conditional differences. WC showed higher SV at rest and a smaller increase in SV than LC (environment-intensity interaction: P = 0.009). The main effect of environment on SV was significant (P = 0.002), but that of dP/dTmax was not (P = 0.155). SV was correlated with dP/dTmax (r = 0.717, P < 0.001). When analysis of covariance (ANCOVA) was performed with dP/dTmax as a covariate, the environment effect on SV was still significant (P < 0.001), although environment-intensity interaction was abolished (P = 0.543). These results suggest that water-based exercise does not elicit unfavorable myocardial oxygen supply-to-demand balance at mild-to-moderate intensity compared with land-based exercise. Rather, water-based exercise may achieve higher SV and better myocardial energy efficiency than land-based exercise, even at the same inotropic force.
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Affiliation(s)
- Marina Fukuie
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.,Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Daisuke Hoshi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan.,Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
| | - Tatsuya Hashitomi
- Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba, Japan
| | - Koichi Watanabe
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Takashi Tarumi
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Jun Sugawara
- Human Informatics and Interaction Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan.,Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
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9
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van der Ster BJP, Kim YS, Westerhof BE, van Lieshout JJ. Central Hypovolemia Detection During Environmental Stress-A Role for Artificial Intelligence? Front Physiol 2021; 12:784413. [PMID: 34975538 PMCID: PMC8715014 DOI: 10.3389/fphys.2021.784413] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 11/18/2021] [Indexed: 11/19/2022] Open
Abstract
The first step to exercise is preceded by the required assumption of the upright body position, which itself involves physical activity. The gravitational displacement of blood from the chest to the lower parts of the body elicits a fall in central blood volume (CBV), which corresponds to the fraction of thoracic blood volume directly available to the left ventricle. The reduction in CBV and stroke volume (SV) in response to postural stress, post-exercise, or to blood loss results in reduced left ventricular filling, which may manifest as orthostatic intolerance. When termination of exercise removes the leg muscle pump function, CBV is no longer maintained. The resulting imbalance between a reduced cardiac output (CO) and a still enhanced peripheral vascular conductance may provoke post-exercise hypotension (PEH). Instruments that quantify CBV are not readily available and to express which magnitude of the CBV in a healthy subject should remains difficult. In the physiological laboratory, the CBV can be modified by making use of postural stressors, such as lower body "negative" or sub-atmospheric pressure (LBNP) or passive head-up tilt (HUT), while quantifying relevant biomedical parameters of blood flow and oxygenation. Several approaches, such as wearable sensors and advanced machine-learning techniques, have been followed in an attempt to improve methodologies for better prediction of outcomes and to guide treatment in civil patients and on the battlefield. In the recent decade, efforts have been made to develop algorithms and apply artificial intelligence (AI) in the field of hemodynamic monitoring. Advances in quantifying and monitoring CBV during environmental stress from exercise to hemorrhage and understanding the analogy between postural stress and central hypovolemia during anesthesia offer great relevance for healthy subjects and clinical populations.
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Affiliation(s)
- Björn J. P. van der Ster
- Department of Internal Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Department of Anesthesiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory for Clinical Cardiovascular Physiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
| | - Yu-Sok Kim
- Laboratory for Clinical Cardiovascular Physiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Department of Internal Medicine, Medisch Centrum Leeuwarden, Leeuwarden, Netherlands
| | - Berend E. Westerhof
- Laboratory for Clinical Cardiovascular Physiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Department of Pulmonary Medicine, Amsterdam University Medical Center, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Johannes J. van Lieshout
- Department of Internal Medicine, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Laboratory for Clinical Cardiovascular Physiology, Amsterdam University Medical Center, University of Amsterdam, Amsterdam, Netherlands
- Medical Research Council Versus Arthritis Centre for Musculoskeletal Ageing Research, Division of Physiology, Pharmacology and Neuroscience, School of Life Sciences, The Medical School, University of Nottingham Medical School, Queen's Medical Centre, Nottingham, United Kingdom
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10
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Claassen JAHR, Thijssen DHJ, Panerai RB, Faraci FM. Regulation of cerebral blood flow in humans: physiology and clinical implications of autoregulation. Physiol Rev 2021; 101:1487-1559. [PMID: 33769101 PMCID: PMC8576366 DOI: 10.1152/physrev.00022.2020] [Citation(s) in RCA: 275] [Impact Index Per Article: 91.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Brain function critically depends on a close matching between metabolic demands, appropriate delivery of oxygen and nutrients, and removal of cellular waste. This matching requires continuous regulation of cerebral blood flow (CBF), which can be categorized into four broad topics: 1) autoregulation, which describes the response of the cerebrovasculature to changes in perfusion pressure; 2) vascular reactivity to vasoactive stimuli [including carbon dioxide (CO2)]; 3) neurovascular coupling (NVC), i.e., the CBF response to local changes in neural activity (often standardized cognitive stimuli in humans); and 4) endothelium-dependent responses. This review focuses primarily on autoregulation and its clinical implications. To place autoregulation in a more precise context, and to better understand integrated approaches in the cerebral circulation, we also briefly address reactivity to CO2 and NVC. In addition to our focus on effects of perfusion pressure (or blood pressure), we describe the impact of select stimuli on regulation of CBF (i.e., arterial blood gases, cerebral metabolism, neural mechanisms, and specific vascular cells), the interrelationships between these stimuli, and implications for regulation of CBF at the level of large arteries and the microcirculation. We review clinical implications of autoregulation in aging, hypertension, stroke, mild cognitive impairment, anesthesia, and dementias. Finally, we discuss autoregulation in the context of common daily physiological challenges, including changes in posture (e.g., orthostatic hypotension, syncope) and physical activity.
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Affiliation(s)
- Jurgen A H R Claassen
- Department of Geriatrics, Radboud University Medical Center, Donders Institute for Brain, Cognition, and Behaviour, Nijmegen, The Netherlands
| | - Dick H J Thijssen
- Department of Physiology, Radboud Institute for Health Sciences, Nijmegen, The Netherlands
- Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Ronney B Panerai
- Department of Cardiovascular Sciences, University of Leicester, Leicester, United Kingdom
- >National Institute for Health Research Leicester Biomedical Research Centre, University of Leicester, Leicester, United Kingdom
| | - Frank M Faraci
- Departments of Internal Medicine, Neuroscience, and Pharmacology, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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11
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Kim YS, van der Ster BJP, Brassard P, Secher NH, van Lieshout JJ. Cerebral vs. Cardiovascular Responses to Exercise in Type 2 Diabetic Patients. Front Physiol 2021; 11:583155. [PMID: 33519500 PMCID: PMC7844205 DOI: 10.3389/fphys.2020.583155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 12/23/2020] [Indexed: 12/17/2022] Open
Abstract
The human brain is constantly active and even small limitations to cerebral blood flow (CBF) may be critical for preserving oxygen and substrate supply, e.g., during exercise and hypoxia. Exhaustive exercise evokes a competition for the supply of oxygenated blood between the brain and the working muscles, and inability to increase cardiac output sufficiently during exercise may jeopardize cerebral perfusion of relevance for diabetic patients. The challenge in diabetes care is to optimize metabolic control to slow progression of vascular disease, but likely because of a limited ability to increase cardiac output, these patients perceive aerobic exercise to be more strenuous than healthy subjects and that limits the possibility to apply physical activity as a preventive lifestyle intervention. In this review, we consider the effects of functional activation by exercise on the brain and how it contributes to understanding the control of CBF with the limited exercise tolerance experienced by type 2 diabetic patients. Whether a decline in cerebral oxygenation and thereby reduced neural drive to working muscles plays a role for "central" fatigue during exhaustive exercise is addressed in relation to brain's attenuated vascular response to exercise in type 2 diabetic subjects.
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Affiliation(s)
- Yu-Sok Kim
- Laboratory for Clinical Cardiovascular Physiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Department of Internal Medicine, Medisch Centrum Leeuwarden, Leeuwarden, Netherlands
| | - Björn J. P. van der Ster
- Laboratory for Clinical Cardiovascular Physiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Department of Anesthesiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
| | - Patrice Brassard
- Department of Kinesiology, Faculty of Medicine, Research Center of the Institut Universitaire de Cardiologie et de Pneumologie de Québec, Université Laval, Québec, QC, Canada
| | - Niels H. Secher
- Department of Anesthesia, The Copenhagen Muscle Research Center, University of Copenhagen, Copenhagen, Denmark
| | - Johannes J. van Lieshout
- Laboratory for Clinical Cardiovascular Physiology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- Department of Medical Biology, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
- MRC/Arthritis Research UK Centre for Musculoskeletal Ageing Research, School of Life Sciences, University of Nottingham Medical School, Queen’s Medical Centre, Nottingham, United Kingdom
- Department of Internal Medicine, Amsterdam UMC, University of Amsterdam, Amsterdam, Netherlands
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12
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Stewart JM, Kota A, O'Donnell-Smith MB, Visintainer P, Terilli C, Medow MS. The preponderance of initial orthostatic hypotension in postural tachycardia syndrome. J Appl Physiol (1985) 2020; 129:459-466. [PMID: 32702262 DOI: 10.1152/japplphysiol.00540.2020] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Reduced systolic/diastolic blood pressure (BP) by >40/20 mmHg defines initial orthostatic hypotension (IOH). Rapid resolution of hypotension and lightheadedness follows, but tachycardia may be prolonged. We aimed to examine IOH in controls and patients with postural tachycardia syndrome (POTS) using indices of spontaneous fluctuations of heart rate (HR) and systolic BP as measures of cardiac baroreflex differences. We recruited otherwise healthy IOH patients without POTS (n = 20, 16 ± 3 yr), healthy volunteers (n = 32, 17 ± 3 yr), and POTS patients (n = 39, 17 ± 4 yr). Subjects were instrumented for electrocardiography and beat-to-beat BP. After 10 min supine, subjects stood for 5 min. Following supine recovery, subjects underwent 70° head-up tilt for 10 min to test for POTS. BP, HR, and time, referenced to standing, were measured at events during standing: minimum BP, BP recovery, peak HR, HR minimum, and steady state. Baseline HR and BP were higher in POTS compared with healthy groups. IOH occurred in 13% of controls and 51% of POTS patients. The BP minimum was lower in POTS. Parasympathetic modulation of cardiac baroreflex was decreased in all POTS and control-IOH subjects. Sympathetic indices were increased. Events following BP minimum occurred progressively later in all POTS and control-IOH subjects compared with non-IOH controls. IOH is more frequent in POTS than in controls with a lower minimum BP. POTS has markedly reduced heart rate variability and baroreflex, indicating reduced HR buffering of BP. POTS-IOH and control-IOH subjects had similar peak HR despite decreased minimum BP in POTS. IOH data indicate modest parasympathetic and cardiovagal baroreflex deficits in control-IOH subjects. Parasympathetic deficits are more severe in all POTS patients.NEW & NOTEWORTHY Significant initial orthostatic hypotension (IOH) occurs in ~50% of postural tachycardia syndrome (POTS) patients and 13% of controls. Heart rate and blood pressure recovery are prolonged in IOH sustaining lightheadedness; IOH is more prevalent and severe in POTS. Altered cerebral blood flow and cardiorespiratory regulation are more prevalent in POTS. Altered heart rate variability and baroreflex gain may cause nearly instantaneous lightheadedness in POTS. IOH alone fails to confer a strong probability of POTS.
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Affiliation(s)
- Julian M Stewart
- Department of Pediatric, New York Medical College, Valhalla, New York.,Department of Physiology, New York Medical College, Valhalla, New York
| | - Archana Kota
- Department of Pediatric, New York Medical College, Valhalla, New York
| | | | - Paul Visintainer
- Baystate Medical Center, University of Massachusetts School of Medicine, Springfield, Massachusetts
| | - Courtney Terilli
- Department of Pediatric, New York Medical College, Valhalla, New York
| | - Marvin S Medow
- Department of Pediatric, New York Medical College, Valhalla, New York.,Department of Physiology, New York Medical College, Valhalla, New York
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13
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Lee SMC, Martin DS, Miller CA, Scott JM, Laurie SS, Macias BR, Mercaldo ND, Ploutz-Snyder L, Stenger MB. Venous and Arterial Responses to Partial Gravity. Front Physiol 2020; 11:863. [PMID: 32848835 PMCID: PMC7399573 DOI: 10.3389/fphys.2020.00863] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2020] [Accepted: 06/26/2020] [Indexed: 01/25/2023] Open
Abstract
Introduction: Chronic exposure to the weightlessness-induced cephalad fluid shift is hypothesized to be a primary contributor to the development of spaceflight-associated neuro-ocular syndrome (SANS) and may be associated with an increased risk of venous thrombosis in the jugular vein. This study characterized the relationship between gravitational level (Gz-level) and acute vascular changes. Methods: Internal jugular vein (IJV) cross-sectional area, inferior vena cava (IVC) diameter, and common carotid artery (CCA) flow were measured using ultrasound in nine subjects (5F, 4M) while seated when exposed to 1.00-Gz, 0.75-Gz, 0.50-Gz, and 0.25-Gz during parabolic flight and while supine before flight (0-G analog). Additionally, IJV flow patterns were characterized. Results: IJV cross-sectional area progressively increased from 12 (95% CI: 9–16) mm2 during 1.00-Gz seated to 24 (13–35), 34 (21–46), 68 (40–97), and 103 (75–131) mm2 during 0.75-Gz, 0.50-Gz, and 0.25-Gz seated and 1.00-Gz supine, respectively. Also, IJV flow pattern shifted from the continuous forward flow observed during 1.00-Gz and 0.75-Gz seated to pulsatile flow during 0.50-Gz seated, 0.25-Gz seated, and 1.00-Gz supine. In contrast, we were unable to detect differences in IVC diameter measured during 1.00-G seated and any level of partial gravity or during 1.00-Gz supine. CCA blood flow during 1.00-G seated was significantly less than 0.75-Gz and 1.00-Gz supine but differences were not detected at partial gravity levels 0.50-Gz and 0.25-Gz. Conclusions: Acute exposure to decreasing Gz-levels is associated with an expansion of the IJV and flow patterns that become similar to those observed in supine subjects and in astronauts during spaceflight. These data suggest that Gz-levels greater than 0.50-Gz may be required to reduce the weightlessness-induced headward fluid shift that may contribute to the risks of SANS and venous thrombosis during spaceflight.
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Affiliation(s)
| | | | | | - Jessica M Scott
- Memorial Sloan Kettering Cancer Center, New York, NY, United States
| | | | | | | | - Lori Ploutz-Snyder
- School of Kinesiology, University of Michigan, Ann Arbor, MI, United States
| | - Michael B Stenger
- Lyndon B. Johnson Space Center, National Aeronautics and Space Administration, Houston, TX, United States
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14
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Matsuzono K, Furuya K, Mashiko T, Ozawa T, Miura K, Suzuki M, Ozawa M, Shimazaki H, Koide R, Tanaka R, Fujimoto S. A new simple method using carotid duplex ultrasonography to assess intracranial vertebrobasilar arterial stenosis. J Neurol Sci 2020; 415:116924. [PMID: 32460146 DOI: 10.1016/j.jns.2020.116924] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 05/10/2020] [Accepted: 05/13/2020] [Indexed: 11/29/2022]
Abstract
OBJECTIVES Magnetic resonance angiography (MRA), three-dimensional computed tomography angiography, and cerebral angiography may be used to assess intracranial vertebrobasilar stenosis. However, these examinations cannot be performed at patients' bedsides. Our purpose was to develop a new bedside method to assess intracranial vertebrobasilar arterial stenosis. METHODS We developed the new method using carotid duplex ultrasonography combined with the head-up test. A total of 141 subjects admitted between June 1, 2017 and March 31, 2019 were enrolled in this study. We calculated vertebral arterial peak systolic velocities (PSVs), end-diastolic velocities (EDVs), and mean velocities (MVs) at 0°, 16°, and 30° head-up angles. Vertebrobasilar arterial stenosis was confirmed using MRA. RESULTS We excluded 28 subjects and included data for 113 subjects and 226 vessels in the final analysis. Cervical vertebral arterial PSV, EDV, and MV gradually decreased from 0° to 30° only in stenotic intracranial vertebral arteries. Sensitivity (probability of detection) was 75.5% and specificity (true negative rate) was 79.7% when EDV at the 30° head-up angle decreased ≥19.5% from the initial 0° head-up angle. Specificity was better (86.4%; sensitivity: 69.4%) when EDV was <9.1 cm/s at the 30° head-up angle. CONCLUSION This new method easily detects intracranial vertebrobasilar arterial stenosis.
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Affiliation(s)
- Kosuke Matsuzono
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Kohei Furuya
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Takafumi Mashiko
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Tadashi Ozawa
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Kumiko Miura
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Masayuki Suzuki
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Misato Ozawa
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Haruo Shimazaki
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Reiji Koide
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Ryota Tanaka
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
| | - Shigeru Fujimoto
- Division of Neurology, Department of Medicine, Jichi Medical University, Tochigi, Japan.
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15
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Klein T, Sanders M, Wollseiffen P, Carnahan H, Abeln V, Askew CD, Claassen JA, Schneider S. Transient cerebral blood flow responses during microgravity. LIFE SCIENCES IN SPACE RESEARCH 2020; 25:66-71. [PMID: 32414494 DOI: 10.1016/j.lssr.2020.03.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 02/23/2020] [Accepted: 03/07/2020] [Indexed: 06/11/2023]
Abstract
PURPOSE A number of studies has well described central cardiovascular changes caused by changing gravity levels as they occur e.g. during parabolic flight. limited data exists describing the effect of microgravity on the cerebrovascular system and brain perfusion. METHODS In this study middle cerebral artery velocity (MCAv) of 16 participants was continuously monitored on a second-by-second basis during 15 consecutive parabolas (1G, 1,8G, 0G, 1,8G) using doppler ultrasound. Simultaneously central cardiovascular parameters (heart rate, mean arterial blood pressure, cardiac output) were assessed. RESULTS Results revealed an immediate reaction of central cardiovascular parameters to changed gravity levels. In contrast, changes in MCAv only initially were in accordance with a normal cerebral autoregulation. Whereas all of the measured central cardiovascular parameters seemed to have reached a steady state after approximately 8 s of microgravity, MCAv, after an initial decrease with the onset of microgravity, increased again during the second half of the microgravity phase. CONCLUSION It is concluded that this increase in MCAv during the second half of the microgravity period reflects a decrease of cerebrovascular resistance caused by a pressure driven increased venous outflow and/or a contraction of precapillary sphincters in order to avoid hyperperfusion of the brain.
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Affiliation(s)
- Timo Klein
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore DC, QLD, Australia; Institute of Movement and Neuroscience, German Sport University Cologne, Cologne, Germany
| | - Marit Sanders
- Department of Geriatric Medicine, Radboud Alzheimer Centre, Radboud University Medical Center, Donders Institute for Brain, Nijmegen, The Netherlands
| | - Petra Wollseiffen
- Institute of Movement and Neuroscience, German Sport University Cologne, Cologne, Germany
| | - Heather Carnahan
- Offshore Safety and Survival Centre, Marine Institute, Memorial University of Newfoundland, Canada
| | - Vera Abeln
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore DC, QLD, Australia
| | - Christopher D Askew
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore DC, QLD, Australia
| | - Jurgen Ahr Claassen
- Department of Geriatric Medicine, Radboud Alzheimer Centre, Radboud University Medical Center, Donders Institute for Brain, Nijmegen, The Netherlands
| | - Stefan Schneider
- VasoActive Research Group, School of Health and Sport Sciences, University of the Sunshine Coast, Maroochydore DC, QLD, Australia; Institute of Movement and Neuroscience, German Sport University Cologne, Cologne, Germany; Offshore Safety and Survival Centre, Marine Institute, Memorial University of Newfoundland, Canada.
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16
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Ogoh S, Sato K, Abreu S, Denise P, Normand H. Arterial and venous cerebral blood flow responses to long‐term head‐down bed rest in male volunteers. Exp Physiol 2019; 105:44-52. [DOI: 10.1113/ep088057] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2019] [Accepted: 11/04/2019] [Indexed: 12/17/2022]
Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering Toyo University Kawagoe‐Shi Saitama Japan
| | - Kohei Sato
- Tokyo Gakugei University Koganei Tokyo Japan
| | - Steven Abreu
- Normandie Université, Unicaen; Inserm Comete GIP Cyceron Chu Caen France
| | - Pierre Denise
- Normandie Université, Unicaen; Inserm Comete GIP Cyceron Chu Caen France
| | - Hervé Normand
- Normandie Université, Unicaen; Inserm Comete GIP Cyceron Chu Caen France
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17
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Ogoh S, Tarumi T. Cerebral blood flow regulation and cognitive function: a role of arterial baroreflex function. J Physiol Sci 2019; 69:813-823. [PMID: 31444691 PMCID: PMC10717347 DOI: 10.1007/s12576-019-00704-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 08/13/2019] [Indexed: 10/26/2022]
Abstract
A strict adequate perfusion pressure via arterial baroreflex for the delivery of oxygen to the tissues of the body is well established; however, the importance of baroreflex for cerebral blood flow (CBF) is unclear. On the other hand, there is convincing evidence for arterial baroreflex function playing an important role in maintaining brain homeostasis, e.g., cerebral metabolism, cerebral hemodynamics, and cognitive function. For example, mild cognitive impairment attenuates the sensitivity of baroreflex, and Alzheimer's disease further decreases it. These clinical findings suggest that CBF and cerebral function are affected by systemic blood pressure regulation via the arterial baroreflex. However, dysfunction of arterial baroreflex is likely to affect CBF regulation as well as the underlying neuronal function, but identifying how this is achieved is arduous since neurological diseases affect systemic as well as cerebral circulation independently. Recent insights into the influence of blood pressure regulation via the arterial baroreflex on cerebral function and blood flow regulation may help elucidate this important question. This review summarizes some update findings regarding direct (autonomic regulation) and indirect (systemic blood pressure regulation) contributions of the arterial baroreflex to the maintenance of cerebral vasculature regulation.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, 2100 Kujirai, Kawagoe, Saitama, 350-8585, Japan.
| | - Takashi Tarumi
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
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18
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The influence of microgravity on cerebral blood flow and electrocortical activity. Exp Brain Res 2019; 237:1057-1062. [PMID: 30741333 DOI: 10.1007/s00221-019-05490-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2018] [Accepted: 02/04/2019] [Indexed: 10/27/2022]
Abstract
Changes in gravity conditions have previously been reported to influence brain hemodynamics as well as neuronal activity. This paper attempts to identify a possible link between changes in brain blood flow and neuronal activity during microgravity. Middle cerebral artery flow velocity (MCAv) was measured using Doppler ultrasound. Brain cortical activity (i.e., cortical current density) was measured using electroencephalography. Finger blood pressure was recorded and exported to generate beat-by-beat systolic (SBP), diastolic (DBP) and mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), and cerebrovascular conductance index (CVCi). Seventeen participants were evaluated under normal gravity conditions and microgravity conditions, during 15 bouts of 22-s intervals of weightlessness during a parabolic flight. Although MAP decreased and CO increased, MCAv remained unchanged in the microgravity condition. CVCi as the quotient of MCAv and MAP increased in microgravity. Cortical current density showed a global decrease. Our data support earlier data reporting a decrease in the amplitude of event-related potentials recorded during microgravity. However, the general decrease in neural excitability in microgravity seems not to be dependent on hemodynamic changes.
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19
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Tomoto T, Imai T, Ogoh S, Maeda S, Sugawara J. Relationship between Aortic Compliance and Impact of Cerebral Blood Flow Fluctuation to Dynamic Orthostatic Challenge in Endurance Athletes. Front Physiol 2018; 9:25. [PMID: 29422868 PMCID: PMC5788908 DOI: 10.3389/fphys.2018.00025] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 01/09/2018] [Indexed: 12/29/2022] Open
Abstract
Aorta effectively buffers cardiac pulsatile fluctuation generated from the left ventricular (LV) which could be a mechanical force to high blood flow and low-resistance end-organs such as the brain. A dynamic orthostatic challenge may evoke substantial cardiac pulsatile fluctuation via the transient increases in venous return and stroke volume (SV). Particularly, this response may be greater in endurance-trained athletes (ET) who exhibit LV eccentric remodeling. The aim of this study was to determine the contribution of aortic compliance to the response of cerebral blood flow fluctuation to dynamic orthostatic challenge in ET and age-matched sedentary (SED) young healthy men. ET (n = 10) and SED (n = 10) underwent lower body negative pressure (LBNP) (-30 mmHg for 4 min) stimulation and release the pressure that initiates a rapid regain of limited venous return and consequent increase in SV. The recovery responses of central and middle cerebral arterial (MCA) hemodynamics from the release of LBNP (~15 s) were evaluated. SV (via Modeflow method) and pulsatile and systolic MCA (via transcranial Doppler) normalized by mean MCA velocity (MCAv) significantly increased after the cessation of LBNP in both groups. ET exhibited the higher ratio of SV to aortic pulse pressure (SV/AoPP), an index of aortic compliance, at the baseline compared with SED (P < 0.01). Following the LBNP release, SV was significantly increased in SED by 14 ± 7% (mean ± SD) and more in ET by 30 ± 15%; nevertheless, normalized pulsatile, systolic, and diastolic MCAv remained constant in both groups. These results might be attributed to the concomitant with the increase in aortic compliance assessed by SV/AoPP. Importantly, the increase in SV/AoPP following the LBNP release was greater in ET than in SED (P < 0.01), and significantly correlated with the baseline SV/AoPP (r = 0.636, P < 0.01). These results suggest that the aortic compliance in the endurance athletes is able to accommodate the additional SV and buffer the potential increase in pulsatility at end-organs such as the brain.
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Affiliation(s)
- Tsubasa Tomoto
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
| | - Tomoko Imai
- Center for General Education, Aichi Institute of Technology, Toyota, Japan
| | - Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Seiji Maeda
- Faculty of Health and Sport Sciences, University of Tsukuba, Tsukuba, Japan
| | - Jun Sugawara
- Human Informatics Research Institute, National Institute of Advanced Industrial Science and Technology, Ibaraki, Japan
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20
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Ogoh S, Moralez G, Washio T, Sarma S, Hieda M, Romero SA, Cramer MN, Shibasaki M, Crandall CG. Effect of increases in cardiac contractility on cerebral blood flow in humans. Am J Physiol Heart Circ Physiol 2017; 313:H1155-H1161. [PMID: 28916637 DOI: 10.1152/ajpheart.00287.2017] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Revised: 09/05/2017] [Accepted: 09/12/2017] [Indexed: 01/17/2023]
Abstract
The effect of acute increases in cardiac contractility on cerebral blood flow (CBF) remains unknown. We hypothesized that the external carotid artery (ECA) downstream vasculature modifies the direct influence of acute increases in heart rate and cardiac function on CBF regulation. Twelve healthy subjects received two infusions of dobutamine [first a low dose (5 μg·kg-1·min-1) and then a high dose (15 μg·kg-1·min-1)] for 12 min each. Cardiac output, blood flow through the internal carotid artery (ICA) and ECA, and echocardiographic measurements were performed during dobutamine infusions. Despite increases in cardiac contractility, cardiac output, and arterial pressure with dobutamine, ICA blood flow and conductance slightly decreased from resting baseline during both low- and high-dose infusions. In contrast, ECA blood flow and conductance increased appreciably during both low- and high-dose infusions. Greater ECA vascular conductance and corresponding increases in blood flow may protect overperfusion of intracranial cerebral arteries during enhanced cardiac contractility and associated increases in cardiac output and perfusion pressure. Importantly, these findings suggest that the acute increase of blood perfusion attributable to dobutamine administration does not cause cerebral overperfusion or an associated risk of cerebral vascular damage.NEW & NOTEWORTHY A dobutamine-induced increase in cardiac contractility did not increase internal carotid artery blood flow despite an increase in cardiac output and arterial blood pressure. In contrast, external carotid artery blood flow and conductance increased. This external cerebral blood flow response may assist with protecting from overperfusion of intracranial blood flow.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe-shi, Saitama, Japan;
| | - Gilbert Moralez
- Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe-shi, Saitama, Japan
| | - Satyam Sarma
- Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Michinari Hieda
- Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Steven A Romero
- Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Matthew N Cramer
- Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
| | - Manabu Shibasaki
- Department of Environmental Health, Nara Women's University, Nara-shi, Nara, Japan
| | - Craig G Crandall
- Institute for Exercise and Environmental Medicine, University of Texas Southwestern Medical Center, Dallas, Texas; and
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21
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Xing CY, Tarumi T, Liu J, Zhang Y, Turner M, Riley J, Tinajero CD, Yuan LJ, Zhang R. Distribution of cardiac output to the brain across the adult lifespan. J Cereb Blood Flow Metab 2017; 37:2848-2856. [PMID: 27789785 PMCID: PMC5536794 DOI: 10.1177/0271678x16676826] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 09/23/2016] [Accepted: 10/04/2016] [Indexed: 11/16/2022]
Abstract
A widely accepted dogma is that about 15-20% of cardiac output is received by the brain in healthy adults under resting conditions. However, it is unclear if the distribution of cardiac output directed to the brain alters across the adult lifespan and is modulated by sex or other hemodynamic variables. We measured cerebral blood flow/cardiac output ratio index in 139 subjects (88 women, age 21-80 years) using phase-contrast magnetic resonance imaging and echocardiography. Body mass index, cardiac systolic function (eject fraction), central arterial stiffness (carotid-femoral pulse wave velocity), arterial pressure, heart rate, physical fitness (VO2 max), and total brain volume were measured to assess their effects on the cardiac output-cerebral blood flow relationship. Cerebral blood flow/cardiac output ratio index decreased by 1.3% per decade associated with decreases in cerebral blood flow ( P < 0.001), while cardiac output remained unchanged. Women had higher cerebral blood flow, lower cardiac output, and thus higher cerebral blood flow/cardiac output ratio index than men across the adult lifespan. Age, body mass index, carotid-femoral pulse wave velocity, and arterial pressure all had negative correlations with cerebral blood flow and cerebral blood flow/cardiac output ratio index ( P < 0.05). Multivariable analysis adjusted for sex, age showed that only body mass index was negatively associated with cerebral blood flow/cardiac output ratio index (β = -0.33, P < 0.001). These findings demonstrated that cardiac output distributed to the brain has sex differences and decreases across the adult lifespan and is inversely associated with body mass index.
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Affiliation(s)
- Chang-Yang Xing
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA
- Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Takashi Tarumi
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA
| | - Jie Liu
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA
- Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Yinan Zhang
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, USA
| | - Marcel Turner
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA
| | - Jonathan Riley
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA
| | - Cynthia Duron Tinajero
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA
| | - Li-Jun Yuan
- Department of Ultrasound Diagnostics, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Rong Zhang
- Institute for Exercise and Environmental Medicine, Texas Health Presbyterian Hospital Dallas, Dallas, USA
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, USA
- Department of Neurology and Neurotherapeutics, University of Texas Southwestern Medical Center, Dallas, USA
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22
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Redistribution of Cerebral Blood Flow during Severe Hypovolemia and Reperfusion in a Sheep Model: Critical Role of α1-Adrenergic Signaling. Int J Mol Sci 2017; 18:ijms18051031. [PMID: 28492488 PMCID: PMC5454943 DOI: 10.3390/ijms18051031] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2017] [Revised: 05/05/2017] [Accepted: 05/08/2017] [Indexed: 11/29/2022] Open
Abstract
Background: Maintenance of brain circulation during shock is sufficient to prevent subcortical injury but the cerebral cortex is not spared. This suggests area-specific regulation of cerebral blood flow (CBF) during hemorrhage. Methods: Cortical and subcortical CBF were continuously measured during blood loss (≤50%) and subsequent reperfusion using laser Doppler flowmetry. Blood gases, mean arterial blood pressure (MABP), heart rate and renal blood flow were also monitored. Urapidil was used for α1A-adrenergic receptor blockade in dosages, which did not modify the MABP-response to blood loss. Western blot and quantitative reverse transcription polymerase chain reactions were used to determine adrenergic receptor expression in brain arterioles. Results: During hypovolemia subcortical CBF was maintained at 81 ± 6% of baseline, whereas cortical CBF decreased to 40 ± 4% (p < 0.001). Reperfusion led to peak CBFs of about 70% above baseline in both brain regions. α1A-Adrenergic blockade massively reduced subcortical CBF during hemorrhage and reperfusion, and prevented hyperperfusion during reperfusion in the cortex. α1A-mRNA expression was significantly higher in the cortex, whereas α1D-mRNA expression was higher in the subcortex (p < 0.001). Conclusions: α1-Adrenergic receptors are critical for perfusion redistribution: activity of the α1A-receptor subtype is a prerequisite for redistribution of CBF, whereas the α1D-receptor subtype may determine the magnitude of redistribution responses.
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Garrett ZK, Pearson J, Subudhi AW. Postural effects on cerebral blood flow and autoregulation. Physiol Rep 2017; 5:5/4/e13150. [PMID: 28242827 PMCID: PMC5328778 DOI: 10.14814/phy2.13150] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 01/10/2017] [Accepted: 01/13/2017] [Indexed: 11/24/2022] Open
Abstract
Cerebral autoregulation (CA) is thought to maintain relatively constant cerebral blood flow (CBF) across normal blood pressures. To determine if postural changes alter CA, we measured cerebral blood flow velocity (CBFv) in the middle cerebral arteries, mean arterial blood pressure (MABP), cardiac output (Q), and end‐tidal carbon dioxide (PETCO2) in 18 healthy individuals (11 female and seven male; 26 ± 9 years) during repeated periods of supine and seated rest. Multiple regression was used to evaluate the influence of PETCO2, MABP, Q, and hydrostatic pressure on CBFv. Static CA was assessed by evaluating absolute changes in steady‐state CBFv. Dynamic CA was assessed by transfer function analysis of the CBFv response to spontaneous oscillations in MABP. In the seated versus supine posture, MABP (67.2 ± 7.2 vs. 84.2 ± 12.1 mmHg; P < 0.001), CBFv (55.2 ± 9.1 vs. 63.6 ± 10.6 cm/sec; P < 0.001) and PETCO2 (29.1 ± 2.6 vs. 30.9 ± 2.3 mmHg; P < 0.001) were reduced. Changes in CBFv were not explained by variance in PETCO2, MABP, Q, or hydrostatic pressure. A reduction in MABP to CBFv transfer function gain while seated (P < 0.01) was explained by changes in the power spectrum of MABP, not CBFv. Our findings suggest that changes in steady‐state cerebral hemodynamics between postures do not appear to have a large functional consequence on the dynamic regulation of CBF.
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Affiliation(s)
- Zachary K Garrett
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado
| | - James Pearson
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado
| | - Andrew W Subudhi
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado
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Ogoh S, Washio T, Sasaki H, Petersen LG, Secher NH, Sato K. Coupling between arterial and venous cerebral blood flow during postural change. Am J Physiol Regul Integr Comp Physiol 2016; 311:R1255-R1261. [DOI: 10.1152/ajpregu.00325.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2016] [Revised: 10/28/2016] [Accepted: 10/28/2016] [Indexed: 11/22/2022]
Abstract
In supine humans the main drainage from the brain is through the internal jugular vein (IJV), but the vertebral veins (VV) become important during orthostatic stress because the IJV is partially collapsed. To identify the effect of this shift in venous drainage from the brain on the cerebral circulation, this study addressed both arterial and venous flow responses in the “anterior” and “posterior” parts of the brain when nine healthy subjects (5 men) were seated and flow was manipulated by hyperventilation and inhalation of 6% carbon dioxide (CO2). From a supine to a seated position, both internal carotid artery (ICA) and IJV blood flow decreased ( P = 0.004 and P = 0.002), while vertebral artery (VA) flow did not change ( P = 0.348) and VV flow increased ( P = 0.024). In both supine and seated positions the ICA response to manipulation of end-tidal CO2 tension was reflected in IJV ( r = 0.645 and r = 0.790, P < 0.001) and VV blood flow ( r = 0.771 and r = 0.828, P < 0.001). When seated, the decrease in ICA blood flow did not affect venous outflow, but the decrease in IJV blood flow was associated with the increase in VV blood flow ( r = 0.479, P = 0.044). In addition, the increase in VV blood flow when seated was reflected in VA blood flow ( r = 0.649, P = 0.004), and the two flows were coupled during manipulation of the end-tidal CO2 tension (supine, r = 0.551, P = 0.004; seated, r = 0.612, P < 0001). These results support that VV compensates for the reduction in IJV blood flow when seated and that VV may influence VA blood flow.
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Affiliation(s)
- Shigehiko Ogoh
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Takuro Washio
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Hiroyuki Sasaki
- Department of Biomedical Engineering, Toyo University, Kawagoe, Japan
| | - Lonnie G. Petersen
- The Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Niels H. Secher
- The Copenhagen Muscle Research Center, Department of Anesthesia, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Kohei Sato
- Research Institute of Physical Fitness, Japan Women’s College of Physical Education, Tokyo, Japan; and
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