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Bertacchini P. Neurofascialvascular training for the treatment of Raynaud's phenomenon: A case report. Mod Rheumatol Case Rep 2024; 8:302-309. [PMID: 38727559 DOI: 10.1093/mrcr/rxae026] [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: 01/18/2024] [Revised: 04/03/2024] [Accepted: 05/09/2024] [Indexed: 07/09/2024]
Abstract
Primary Raynaud's phenomenon (PRP) is characterised by episodic, reversible, and disabling vasospasms of the peripheral arteries. In the most severe cases, it can lead to ulceration of the fingers and toes. Neuro fascial VascularTraining (NFVT) is a novel therapeutic approach for treating PRP. NFVT aims to enhance peripheral circulation and stimulate the autonomic nervous system (ANS) by engaging multiple physiological mechanisms simultaneously. This integrated approach works to reduce vasospasms and alleviate associated symptoms through neurodynamic and myofascial interventions. A 54-year-old woman, who has experienced pain and hypoesthesia in her hands for 9 years, received a diagnosis of PRP without systemic sclerosis in 2014. The patient reported daily colour changes in her fingers, along with pain and a temporary decrease in tactile sensitivity. The patient engaged in ten 30-minute exercise sessions, and the clinical outcomes were assessed based on several parameters. These included the frequency and duration of vasospastic attacks, evaluated using the Raynaud Condition Score, as well as pain and tingling, measured through the daily Numeric Rating Scale. The Composite Autonomic Symptom Score (COMPASS 31) was utilised to assess dysautonomia, while the frequency of medication use and the Disabilities of the Arm, Shoulder, and Hand questionnaire were also considered. The results indicated a significant improvement in symptoms. NFVT improved symptoms and motor dysfunction in a patient with Raynaud's syndrome, demonstrating how NFVT can increase peripheral blood flow, stimulate the ANS, and improve symptoms in PRP.
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Affiliation(s)
- Paolo Bertacchini
- Master OMPT, University of Bologna, Bologna, Emilia-Romagna 40138, Italy
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2
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Schwartz JL, Fongwoo TA, Bentley RF. The effect of self-identified arm dominance on exercising forearm hemodynamics and skeletal muscle desaturation. PLoS One 2024; 19:e0305539. [PMID: 38885214 PMCID: PMC11182511 DOI: 10.1371/journal.pone.0305539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2024] [Accepted: 06/01/2024] [Indexed: 06/20/2024] Open
Abstract
The human forearm model is commonly employed in physiological investigations exploring local vascular function and oxygen delivery; however, the effect of arm dominance on exercising forearm hemodynamics and skeletal muscle oxygen saturation (SmO2) in untrained individuals is poorly understood. Therefore, the purpose of this study was to explore the effect of self-identified arm dominance on forearm hemodynamics and SmO2 in untrained individuals during submaximal, non-ischemic forearm exercise. Twenty healthy individuals (23±4 years, 50% female; 80% right-handed) completed three-minute bouts of supine rhythmic (1 second contraction: 2 second relaxation duty cycle) forearm handgrip exercise at both absolute (10kg; 98N) and relative (30% of maximal voluntary contraction) intensities in each forearm. Beat-by-beat measures of forearm blood flow (FBF; ml/min), mean arterial blood pressure (MAP; mmHg) and flexor digitorum superficialis SmO2 (%) were obtained throughout and averaged during the final 30 seconds of rest, exercise, and recovery while forearm vascular conductance was calculated (FVC; ml/min/100mmHg). Data are Δ from rest (mean±SD). Absolute force production did not differ between non-dominant and dominant arms (97±11 vs. 98±13 N, p = 0.606) whereas relative force production in females did (69±24 vs. 82±25 N, p = 0.001). At both exercise intensities, FBFRELAX, FVCRELAX, MAPRELAX, and the time constant tau for FBF and SmO2 were unaffected by arm dominance (all p>0.05). While arm dominance did not influence SmO2 during absolute intensity exercise (p = 0.506), the non-dominant arm in females experienced an attenuated reduction in SmO2 during relative intensity exercise (-14±10 vs. -19±8%, p = 0.026)-though exercise intensity was also reduced (p = 0.001). The present investigation has demonstrated that arm dominance in untrained individuals does not impact forearm hemodynamics or SmO2 during handgrip exercise.
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Affiliation(s)
- Jacob L. Schwartz
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Trishawna A. Fongwoo
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Robert F. Bentley
- Faculty of Kinesiology & Physical Education, University of Toronto, Toronto, Ontario, Canada
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3
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Leach OK, Gifford JR, Mack GW. Rapid onset vasodilation during baroreceptor loading and unloading. Am J Physiol Regul Integr Comp Physiol 2023; 325:R568-R575. [PMID: 37694334 DOI: 10.1152/ajpregu.00116.2023] [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: 05/17/2023] [Revised: 08/21/2023] [Accepted: 09/05/2023] [Indexed: 09/12/2023]
Abstract
The purpose of these experiments was to determine if the increase in vascular conductance following a single muscle contraction (50% of maximal voluntary contraction) (6 male and 6 female subjects) was altered during baroceptor loading and unloading. Rapid onset vasodilation (ROV) was determined by measuring brachial artery blood flow (Doppler ultrasound) and blood pressure (Finapress monitor). Brachial artery vascular conductance was calculated by dividing blood flow by mean arterial pressure. ROV was described by the area under the Δvascular conductance (VC)-time curve during the 30 s following muscle contraction. ROV was determined using chamber pressures of +20, +10, 0, -10, -20, and -40 mmHg (lower body positive and negative pressure, LBPP, and LBNP). We tested the hypothesis that the impact of baroreceptor loading and unloading produces a proportion change in ROV. The level of ROV following each contraction was proportional to the peak force (r2 = 0.393, P = 0.0001). Peak force was therefore used as a covariate in further analysis. ROV during application of -40 mmHg LBNP (0.345 ± 0.229 mL·mmHg-1) was lower than that observed at Control (0.532 ± 0.284 mL·mmHg-1, P = 0.034) and +20 mmHg LBPP (0.658 ± 0.364 mL·mmHg-1, P = 0.0008). ROV was linearly related to chamber pressure from -40 to +20 mmHg chamber pressure (r2 = 0.512, P = 0.022, n = 69) and from -20 to +10 mmHg chamber pressure (r2= 0.973, P < 0.0425, n = 45), Overall, vasoconstrictor tone altered with physiologically relevant baroreceptor loading and unloading resulted in a proportion change in ROV.NEW & NOTEWORTHY Rapid onset vasodilation (ROV) was linearly related to the peak force of each single 1-s muscle contraction. In addition, ROV is reduced by baroreceptor unloading (LBNP: -10, -120, and -40 mmHg) and increased by baroreceptor loading (LBPP: +10 and +20 mmHg). Without accounting for peak force and the level of baroreceptor engagement makes comparison of ROV in subjects of differing muscle size or strength untenable.
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Affiliation(s)
- Olivia K Leach
- Department of Exercise Sciences, Brigham Young University, Provo, Utah, United States
| | - Jayson R Gifford
- Department of Exercise Sciences, Brigham Young University, Provo, Utah, United States
| | - Gary W Mack
- Department of Exercise Sciences, Brigham Young University, Provo, Utah, United States
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4
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Soto-Rodríguez FJ, Cabañas EI, Pérez-Mármol JM. Impact of prolonged sitting interruption strategies on shear rate, flow-mediated dilation and blood flow in adults: A systematic review and meta-analysis of randomized cross-over trials. J Sports Sci 2022; 40:1558-1567. [PMID: 35731706 DOI: 10.1080/02640414.2022.2091347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Prolonged sitting has been shown to affect endothelial function. Strategies that promote interruption of sitting have shown varying results on the shear rate (SR), flow-mediated dilation (FMD) and blood flow (BF). Thus, we conducted a systematic review and meta-analysis to 1) increase the existing knowledge of the impact of sitting interruption in the prevention of endothelial dysfunction in adults and 2) determine the effect of the sitting interruption strategies on SR, FMD, BF. Literature search was carried out through 7 databases. A random effects model was used to provide the overall mean difference with a 95%CI, and forest plots were generated for pooled estimates of each study outcome. Assessment of biases was performed using ROB2 and considerations for crossover trials. Prolonged sitting interruption strategies showed a significant effect in increasing SR (MD: 7.58 s-1; 95% CI: 3.00 to 12.17), FMD (MD: 1.74%; 95% CI: 0.55 to 2.93) and BF (MD: 12.08 ml/min; 95% CI: 7.61 to 16.55) when compared with the uninterrupted prolonged sitting condition. Prolonged sitting interruption strategies significantly increase SR, FMD and BF, therefore, they represent a considerable effective preventive method on endothelial dysfunction caused by acute exposure to uninterrupted prolonged sitting.
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Affiliation(s)
- Francisco Javier Soto-Rodríguez
- Programa de Doctorado en Medicina Clínica y Salud Pública, Universidad de Granada, Granada, Spain.,Facultad de Medicina, Departamento de Medicina Interna, Universidad de La Frontera, Temuco, Chile.,Facultad de Ciencias de la Salud, Carrera de Kinesiología, Universidad Autónoma de Chile, Temuco, Chile
| | - Eva Isidoro Cabañas
- Programa de Doctorado en Medicina Clínica y Salud Pública, Universidad de Granada, Granada, Spain.,Hospital Virgen de las Nieves, Granada, España
| | - José Manuel Pérez-Mármol
- Departamento de Fisioterapia, Facultad de Ciencias de la Salud, Universidad de Granada, Granada, Spain.,Instituto de Investigación Biosanitaria (ibs.GRANADA), Granada, Spain
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5
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Boulton D, Taylor CE, Green S, Macefield VG. The Role of Central Command in the Increase in Muscle Sympathetic Nerve Activity to Contracting Muscle During High Intensity Isometric Exercise. Front Neurosci 2021; 15:770072. [PMID: 34924937 PMCID: PMC8675906 DOI: 10.3389/fnins.2021.770072] [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: 09/03/2021] [Accepted: 11/01/2021] [Indexed: 11/13/2022] Open
Abstract
We previously demonstrated that muscle sympathetic nerve activity (MSNA) increases to contracting muscle as well as to non-contracting muscle, but this was only assessed during isometric exercise at ∼10% of maximum voluntary contraction (MVC). Given that high-intensity isometric contractions will release more metabolites, we tested the hypothesis that the metaboreflex is expressed in the contracting muscle during high-intensity but not low-intensity exercise. MSNA was recorded continuously via a tungsten microelectrode inserted percutaneously into the right common peroneal nerve in 12 participants, performing isometric dorsiflexion of the right ankle at 10, 20, 30, 40, and 50% MVC for 2 min. Contractions were immediately followed by 6 min of post-exercise ischemia (PEI); 6 min of recovery separated contractions. Cross-correlation analysis was performed between the negative-going sympathetic spikes of the raw neurogram and the ECG. MSNA increased as contraction intensity increased, reaching mean values (± SD) of 207 ± 210 spikes/min at 10% MVC (P = 0.04), 270 ± 189 spikes/min at 20% MVC (P < 0.01), 538 ± 329 spikes/min at 30% MVC (P < 0.01), 816 ± 551 spikes/min at 40% MVC (P < 0.01), and 1,097 ± 782 spikes/min at 50% MVC (P < 0.01). Mean arterial pressure also increased in an intensity-dependent manner from 76 ± 3 mmHg at rest to 90 ± 6 mmHg (P < 0.01) during contractions of 50% MVC. At all contraction intensities, blood pressure remained elevated during PEI, but MSNA returned to pre-contraction levels, indicating that the metaboreflex does not contribute to the increase in MSNA to contracting muscle even at these high contraction intensities.
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Affiliation(s)
- Daniel Boulton
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Chloe E Taylor
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia
| | - Simon Green
- School of Science and Health, Western Sydney University, Sydney, NSW, Australia.,Neuroscience Research Australia, Sydney, NSW, Australia
| | - Vaughan G Macefield
- Neuroscience Research Australia, Sydney, NSW, Australia.,School of Medicine, Western Sydney University, Sydney, NSW, Australia.,Baker Heart and Diabetes Institute, Melbourne, VIC, Australia
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6
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Amin SB, Mugele H, Dobler FE, Marume K, Moore JP, Lawley JS. Intra-rater reliability of leg blood flow during dynamic exercise using Doppler ultrasound. Physiol Rep 2021; 9:e15051. [PMID: 34617675 PMCID: PMC8496156 DOI: 10.14814/phy2.15051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 08/30/2021] [Accepted: 08/31/2021] [Indexed: 11/24/2022] Open
Abstract
Developing an exercise model that resembles a traditional form of aerobic exercise and facilitates a complete simultaneous assessment of multiple parameters within the oxygen cascade is critically for understanding exercise intolerances in diseased populations. Measurement of muscle blood flow is a crucial component of such a model and previous studies have used invasive procedures to determine blood flow kinetics; however, this may not be appropriate in certain populations. Furthermore, current models utilizing Doppler ultrasound use isolated limb exercise and while these studies have provided useful data, the exercise model does not mimic the whole-body physiological response to continuous dynamic exercise. Therefore, we aimed to measure common femoral artery blood flow using Doppler ultrasound during continuous dynamic stepping exercise performed at three independent workloads to assess the within day and between-day reliability for such an exercise modality. We report a within-session coefficient of variation of 5.8% from three combined workloads and a between-day coefficient of variation of 12.7%. These values demonstrate acceptable measurement accuracy and support our intention of utilizing this noninvasive exercise model for an integrative assessment of the whole-body physiological response to exercise in a range of populations.
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Affiliation(s)
- Sachin B. Amin
- Department Sport ScienceDivision of Performance Physiology and PreventionUniversity InnsbruckInnsbruckAustria
| | - Hendrik Mugele
- Department Sport ScienceDivision of Performance Physiology and PreventionUniversity InnsbruckInnsbruckAustria
| | - Florian E. Dobler
- Department Sport ScienceDivision of Performance Physiology and PreventionUniversity InnsbruckInnsbruckAustria
| | | | | | - Justin S. Lawley
- Department Sport ScienceDivision of Performance Physiology and PreventionUniversity InnsbruckInnsbruckAustria
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7
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Hill EC, Housh TJ, Smith CM, Keller JL, Anders JPV, Schmidt RJ, Johnson GO. Acute changes in muscle thickness, edema, and blood flow are not different between low-load blood flow restriction and non-blood flow restriction. Clin Physiol Funct Imaging 2021; 41:452-460. [PMID: 34192417 DOI: 10.1111/cpf.12720] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 06/05/2021] [Accepted: 06/22/2021] [Indexed: 11/28/2022]
Abstract
The purpose of the present study was to examine the acute changes in muscle swelling (as assessed by muscle thickness and echo intensity) and muscle blood flow associated with an acute bout of low-load blood flow restriction (LLBFR) and low-load non-blood flow restriction (LL) exercise. Twenty women (mean ± SD; 22 ± 2years) volunteered to perform an acute exercise bout that consisted of 75 (1 × 30, 3 × 15) isokinetic, reciprocal, concentric-only, submaximal (30% of peak torque), forearm flexion and extension muscle actions. Pretest, immediately after (posttest), and 5-min after (recovery) completing the 75 repetitions, muscle thickness and echo intensity were assessed from the biceps brachii and triceps brachii muscles and muscle blood flow was assessed from the brachial artery. There were no between group differences for any of the dependent variables, but there were significant simple and main effects for muscle and time. Biceps and triceps brachii muscle thickness increased from pretest (2.13 ± 0.39 cm and 1.88 ± 0.40 cm, respectively) to posttest (2.58 ± 0.49 cm and 2.17 ± 0.43 cm, respectively) for both muscles and remained elevated for the biceps brachii (2.53 ± 0.43 cm), but partially returned to pretest levels for the triceps brachii (2.06 ± 0.41 cm). Echo intensity and muscle blood flow increased from pretest (98.0 ± 13.6 Au and 94.5 ± 31.6 ml min-1 , respectively) to posttest (109.2 ± 16.9 Au and 312.2 ± 106.5 ml min-1 , respectively) and pretest to recovery (110.1 ± 18.3 Au and 206.7 ± 92.9 ml min-1 , respectively) and remained elevated for echo intensity, but partially returned to pretest levels for muscle blood flow. The findings of the present study indicated that LLBFR and LL elicited comparable acute responses as a result of reciprocal, concentric-only, forearm flexion and extension muscle actions.
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Affiliation(s)
- Ethan C Hill
- School of Kinesiology & Physical Therapy, Division of Kinesiology, University of Central Florida, Orlando, FL, USA.,Florida Space Institute, University of Central Florida, Orlando, FL, USA
| | - Terry J Housh
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Cory M Smith
- College of Health Sciences, Department of Kinesiology, University of Texas at El Paso, El Paso, TX, USA
| | - Joshua L Keller
- College of Education and Professional Studies, Department of Health, Kinesiology and Sport, University of South Alabama, Mobile, AL, USA
| | - John Paul V Anders
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Richard J Schmidt
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
| | - Glen O Johnson
- Department of Nutrition and Health Sciences, Human Performance Laboratory, University of Nebraska-Lincoln, Lincoln, NE, USA
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8
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Lopez C, Taivassalo T, Berru MG, Saavedra A, Rasmussen HC, Batra A, Arora H, Roetzheim AM, Walter GA, Vandenborne K, Forbes SC. Postcontractile blood oxygenation level-dependent (BOLD) response in Duchenne muscular dystrophy. J Appl Physiol (1985) 2021; 131:83-94. [PMID: 34013753 PMCID: PMC8325615 DOI: 10.1152/japplphysiol.00634.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Revised: 04/28/2021] [Accepted: 05/13/2021] [Indexed: 11/22/2022] Open
Abstract
Duchenne muscular dystrophy (DMD) is characterized by a progressive replacement of muscle by fat and fibrous tissue, muscle weakness, and loss of functional abilities. Impaired vasodilatory and blood flow responses to muscle activation have also been observed in DMD and associated with mislocalization of neuronal nitric oxide synthase mu (nNOSμ) from the sarcolemma. The objective of this study was to determine whether the postcontractile blood oxygen level-dependent (BOLD) MRI response is impaired in DMD and correlated with established markers of disease severity in DMD, including MRI muscle fat fraction (FF) and clinical functional measures. Young boys with DMD (n = 16, 5-14 yr) and unaffected controls (n = 16, 5-14 yr) were evaluated using postcontractile BOLD, FF, and functional assessments. The BOLD response was measured following five brief (2 s) maximal voluntary dorsiflexion contractions, each separated by 1 min of rest. FFs from the anterior compartment lower leg muscles were quantified via chemical shift-encoded imaging. Functional abilities were assessed using the 10 m walk/run and the 6-min walk distance (6MWD). The peak BOLD responses in the tibialis anterior and extensor digitorum longus were reduced (P < 0.001) in DMD compared with controls. Furthermore, the anterior compartment peak BOLD response correlated with function (6MWD ρ = 0.87, P < 0.0001; 10 m walk/run time ρ = -0.78, P < 0.001) and FF (ρ = -0.52, P = 0.05). The reduced postcontractile BOLD response in DMD may reflect impaired microvascular function. The relationship observed between the postcontractile peak BOLD response and functional measures and FF suggests that the BOLD response is altered with disease severity in DMD.NEW & NOTEWORTHY This study examined the postcontractile blood oxygen level-dependent (BOLD) response in boys with Duchenne muscular dystrophy (DMD) and unaffected controls, and correlated this measure to markers of disease severity. Our findings indicate that the postcontractile BOLD response is impaired in DMD after brief muscle contractions, is correlated to disease severity, and may be valuable to implement in future studies to evaluate treatments targeting microvascular function in DMD.
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Affiliation(s)
- Christopher Lopez
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Tanja Taivassalo
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Maria G Berru
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Andres Saavedra
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Hannah C Rasmussen
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Abhinandan Batra
- Department of Physical Therapy, University of Florida, Gainesville, Florida
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Harneet Arora
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Alex M Roetzheim
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Glenn A Walter
- Department of Physiology and Functional Genomics, University of Florida, Gainesville, Florida
| | - Krista Vandenborne
- Department of Physical Therapy, University of Florida, Gainesville, Florida
| | - Sean C Forbes
- Department of Physical Therapy, University of Florida, Gainesville, Florida
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9
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Influence of muscular contraction on vascular conductance during exercise above versus below critical power. Respir Physiol Neurobiol 2021; 293:103718. [PMID: 34126260 DOI: 10.1016/j.resp.2021.103718] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Revised: 06/02/2021] [Accepted: 06/08/2021] [Indexed: 11/20/2022]
Abstract
We tested the hypothesis that limb vascular conductance (LVC) would increase during the immediate recovery phase of dynamic exercise above, but not below, critical power (CP) indicating a threshold for muscular contraction-induced impedance of limb blood flow (LBF). CP (115 ± 26 W) was determined in 7 men and 7 women who subsequently performed ∼5 min of near-supine cycling exercise both below and above CP. LVC demonstrated a greater increase during immediate recovery and remained significantly higher following exercise above, compared to below, CP (all p < 0.001). Power output was associated with the immediate increases in LVC following exercise above, but not below, CP (p < 0.001; r = 0.85). Additionally, variance in percent LBF impedance was significantly lower above (CV: 10.7 %), compared to below (CV: 53.2 %), CP (p < 0.01). CP appears to represent a threshold above which the characteristics of LBF impedance by muscular contraction become intensity-dependent. These data suggest a critical level of LBF impedance relative to contraction intensity exists and, once attained, may promote the progressive metabolic and neuromuscular responses known to occur above CP.
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10
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Thorn CE, Adio AO, Fox RH, Gardner AM, Winlove CP, Shore AC. Intermittent compression induces transitory hypoxic stimuli, upstream vasodilation and enhanced perfusion of skin capillaries, independent of age and diabetes. J Appl Physiol (1985) 2021; 130:1072-1084. [PMID: 33571053 DOI: 10.1152/japplphysiol.00657.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The benefit of enhanced shear stress to the vascular endothelium has been well-documented in conduit arteries but is less understood in skin microcirculation. The aim of this study was to provide physiological evidence of the vascular changes in skin microcirculation induced by intermittent pneumatic compression (IPC) of 1 s cuff inflation (130 mmHg) every 20 s to the palm of the hand for 30 min. The oxygenation and hemodynamics of dorsal mid-phalangeal finger skin microcirculation were assessed by laser Doppler fluximetry and reflectance spectroscopy before, during, and after IPC in 15 young (18-39 years old) and 39 older (40-80 years old) controls and 32 older subjects with type 2 diabetes mellitus. Each individual cuff inflation induced: 1) brief surge in flux immediately after cuff deflation followed by 2) transitory reduction in blood oxygen for ∼4 s, and 3) a second increase in perfusion and oxygenation of the microcirculation peaking ∼11 s after cuff deflation in all subject groups. With no significant change in blood volume observed by reflectance spectroscopy, despite the increased shear stress at the observed site, this second peak in flux and blood oxygen suggests a delayed vasoactive response upstream inducing increased arterial influx in the microcirculation that was higher in older controls and subjects with diabetes compared to young controls (P < 0.001, P < 0.001, respectively) and achieving maximum capillary recruitment in all subject groups. Transitory hypoxic stimuli with conducted vasodilation may be a mechanism through which IPC enhances capillary perfusion in skin microcirculation independent of age and type 2 diabetes mellitus.NEW & NOTEWORTHY This study demonstrates that hand intermittent pneumatic compression evokes transitory hypoxic stimuli in distal finger skin microcirculation inducing vasodilation of arterial inflow vessels, enhanced perfusion, and maximum capillary recruitment in young and older subjects and older subjects with type 2 diabetes mellitus. Enhanced shear stress in the microcirculation did not appear to induce local skin vasodilation.
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Affiliation(s)
- Clare E Thorn
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Aminat O Adio
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Roger H Fox
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - A Michael Gardner
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - C Peter Winlove
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
| | - Angela C Shore
- Diabetes and Vascular Medicine, Institute of Biomedical and Clinical Sciences, University of Exeter Medical School, College of Medicine and Health and NIHR Exeter Clinical Research Facility, and School of Physics and Astronomy, University of Exeter, Exeter, United Kingdom
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11
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Liu Y, Jiang N, Pang F, Chen T. Resistance Training with Blood Flow Restriction on Vascular Function: A Meta-analysis. Int J Sports Med 2021; 42:577-587. [PMID: 33735919 DOI: 10.1055/a-1386-4846] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In this meta-analysis, the aims were to examine the effects of resistance training with and without blood flow restriction on vascular function. Five databases were searched up to June 2020 for papers about resistance training with blood flow restriction influence on vascular function. The quality of each identified study was evaluated. Effect sizes were estimated in terms of the standardized mean difference. A subgroup analysis was conducted according to participants' age, training duration, and cuff pressure. The results of six studies on arterial compliance and five on vascular function were highly homogenous regarding responses to resistance training with or without blood flow restriction. Resistance training with blood flow restriction had a more positive effect for regulating arterial compliance than resistance training without blood flow restriction, but not for vascular function. Resistance training with blood flow restriction leads to a more positive effect on vascular function than resistance training when training for no longer than four weeks.
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Affiliation(s)
- Yujia Liu
- Department of Physical Education, Jiangsu Normal University, Xuzhou, China
| | - Ning Jiang
- Department of Orthopedics, Fifth Affiliated Hospital of Sun Yat-sen University, Zhuhai, China
| | - Fangfang Pang
- Department of Emergency, Haigang Hospital of Yantai City, Yantai, China
| | - Tong Chen
- Department of Marxism Studies, Jiangsu Normal University, Xuzhou, China
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12
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Kaur J, Barbosa TC, Nandadeva D, Young BE, Stephens BY, Brothers RM, Fadel PJ. Attenuated Rapid-Onset Vasodilation to Forearm Muscle Contraction in Black Men. Med Sci Sports Exerc 2021; 53:590-596. [PMID: 32910095 PMCID: PMC7909956 DOI: 10.1249/mss.0000000000002511] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
PURPOSE Non-Hispanic Black individuals have a blunted ability to vasodilate at rest compared with other racial groups. Limited studies have investigated blood flow responses to exercise in Black individuals. Recently, our laboratory demonstrated that Black men exhibit attenuated increases in forearm vascular conductance (FVC) during steady-state rhythmic handgrip. The mechanisms for this remain unknown. Herein, we used single muscle contractions, a modality that allows for assessment of rapid-onset vasodilation (ROV) independent of major elevations in shear stress, tissue metabolism, and systemic hemodynamics. METHODS Ten young, healthy Black and White men performed single forearm contractions at 20%, 40%, and 60% maximal voluntary contraction (MVC). In addition, cuff inflations were performed on the forearm to examine the contribution of mechanical compression to ROV. Forearm blood flow (FBF; duplex Doppler ultrasound), heart rate (ECG), and mean arterial pressure (Finometer) were continuously measured. FVC was calculated as FBF/mean arterial pressure. RESULTS Baseline FVC (White men vs Black men, 0.75 ± 0.11 vs 0.80 ± 0.09 mL·min-1·mm Hg-1; P = 0.73), FBF, and MVCs (White men vs Black men, 54 ± 2 vs 54 ± 2 kg; P = 0.95) were similar between the groups. After single contractions, both groups exhibited intensity-dependent FVC and FBF increases during ROV; however, these responses were attenuated in the Black group at all intensities (e.g., 60%MVC FVC: White men vs Black men, +371% ± 37% vs +220% ± 23% baseline; P = 0.001). FVC and FBF responses to cuff inflation alone were also attenuated in Black individuals (P < 0.001). CONCLUSIONS Collectively, these data indicate that Black men have an overall blunted ability to rapidly vasodilate compared with young White men.
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Affiliation(s)
- Jasdeep Kaur
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX
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13
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Hanson BE, Joyner MJ, Casey DP. Sex-related differences in rapid-onset vasodilation: impact of aging. J Appl Physiol (1985) 2021; 130:206-214. [PMID: 33119464 DOI: 10.1152/japplphysiol.00663.2020] [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] [Indexed: 11/22/2022] Open
Abstract
Rapid-onset vasodilation (ROV) in response to a single muscle contraction is attenuated with aging. Moreover, sex-related differences in muscle blood flow and vasodilation during dynamic exercise have been observed in young and older adults. The purpose of the present study was to explore if sex-related differences in ROV exist in young (n = 36, 25 ± 1 yr) and older (n = 32, 66 ± 1 yr) adults. Subjects performed single forearm contractions at 10%, 20%, and 40% maximal voluntary contraction. Brachial artery blood velocity and diameter were measured with Doppler ultrasound, and forearm vascular conductance (mL·min-1·100 mmHg-1) was calculated from blood flow (mL·min-1) and mean arterial pressure (mmHg) and used as a measure of ROV. Peak ROV was attenuated in women across all relative intensities in the younger and older groups (P < 0.05). In a subset of subjects with similar absolute workloads (∼5 kg and ∼11 kg), age-related differences in ROV were observed among both women and men (P < 0.05). However, only older women demonstrated an attenuated peak ROV compared with men (91 ± 6 vs. 121 ± 11 mL·min-1·100 mmHg-1, P < 0.05), a difference not observed in the young group (134 ± 8 vs. 154 ± 11 mL·min-1·100 mmHg-1, P = 0.15). Additionally, examining the slope of peak ROV across contraction intensities indicated a blunted response in older women compared with their younger counterparts (P < 0.05), with no differences observed between older and young men (P = 0.38). Our data suggest that sex-related differences in the rapid vasodilatory response to single muscle contractions exist in older but not young adults, such that older women have a blunted response compared with older men.NEW & NOTEWORTHY While rapid-onset vasodilation (ROV) has been shown to decrease in older individuals, it is unclear if sex contributes to the decline with aging. We sought to identify if sex-related differences exist in the ROV response to single forearm contractions in young and older adults. Our data suggest sex-related differences are present among older but not young individuals, with women having an attenuated response. These data indicate sex plays a role in decreased vasodilation with aging.
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Affiliation(s)
- Brady E Hanson
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Michael J Joyner
- Department of Anesthesiology and Perioperative Medicine, Mayo Clinic, Rochester, Minnesota
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Abboud Cardiovascular Research Center, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
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14
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Hill EC, Housh TJ, Smith CM, Keller JL, Schmidt RJ, Johnson GO. High- vs. Low-Intensity Fatiguing Eccentric Exercise on Muscle Thickness, Strength, and Blood Flow. J Strength Cond Res 2021; 35:33-40. [DOI: 10.1519/jsc.0000000000002632] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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15
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Ichinose M, Nakabayashi M, Ono Y. Rapid vasodilation within contracted skeletal muscle in humans: new insight from concurrent use of diffuse correlation spectroscopy and Doppler ultrasound. Am J Physiol Heart Circ Physiol 2020; 320:H654-H667. [PMID: 33337963 DOI: 10.1152/ajpheart.00761.2020] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Previous studies showed that conduit artery blood flow rapidly increases after even a brief contraction of muscles within the dependent limb. Whether this rapid hyperemia occurs within contracted skeletal muscle in humans has yet to be confirmed, however. We therefore used diffuse correlation spectroscopy (DCS) to characterize the rapid hyperemia and vasodilatory responses within the muscle microvasculature induced by single muscle contractions in humans. Twenty-five healthy male volunteers performed single 1-s isometric handgrips at 20%, 40%, 60%, and 80% of maximum voluntary contraction. DCS probes were placed on the flexor digitorum superficialis muscle, and a skeletal muscle blood flow index (SMBFI) was derived continuously. At the same time, brachial artery blood flow (BABF) responses were measured using Doppler ultrasound. Single muscle contractions evoked rapid, monophasic increases in both SMBFI and BABF that occurred within 3 s after release of contraction. The initial and peak responses increased with increases in contraction intensity and were greater for BABF than for SMBFI at all intensities. BABF reached its peak within 5 to 8 s after the end of contraction. The SMBFI continued to increase after the BABF passed its peak and was decreasing toward the resting level and peaked about 10 to 15 s after completion of the contraction. We conclude that single muscle contractions induce rapid, intensity-dependent hyperemia within the contracted skeletal muscle microvasculature. Moreover, the characteristics of the rapid hyperemia and vasodilatory responses of skeletal muscle microvessels differ from those simultaneously evaluated in the upstream conduit artery.NEW & NOTEWORTHY Through the concurrent use of diffuse correlation spectroscopy and Doppler ultrasound, we provide the first evidence in humans that a single brief muscle contraction evokes rapid, intensity-dependent hyperemia within the contracted skeletal muscle microvasculature and the upstream conduit artery. We also show that the magnitude and time course of the contraction-induced rapid hyperemia and vasodilatory responses within skeletal muscle microvessels significantly differ from those in the conduit artery.
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Affiliation(s)
- Masashi Ichinose
- Human Integrative Physiology Laboratory, School of Business Administration, Meiji University, Tokyo, Japan
| | - Mikie Nakabayashi
- Graduate School of Science and Technology, Meiji University, Kanagawa, Japan
| | - Yumie Ono
- Department of Electronics and Bioinformatics, School of Science and Technology, Meiji University, Kanagawa, Japan
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16
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Gifford JR, Hanson BE, Proffit M, Wallace T, Kofoed J, Griffin G, Hanson M. Indices of leg resistance artery function are independently related to cycling V̇O 2 max. Physiol Rep 2020; 8:e14551. [PMID: 32812353 PMCID: PMC7435036 DOI: 10.14814/phy2.14551] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Accepted: 07/26/2020] [Indexed: 12/30/2022] Open
Abstract
PURPOSE While maximum blood flow influences one's maximum rate of oxygen consumption (V̇O2 max), with so many indices of vascular function, it is still unclear if vascular function is related to V̇O2 max in healthy, young adults. The purpose of this study was to determine if several common vascular tests of conduit artery and resistance artery function provide similar information about vascular function and the relationship between vascular function and V̇O2 max. METHODS Twenty-two healthy adults completed multiple assessments of leg vascular function, including flow-mediated dilation (FMD), reactive hyperemia (RH), passive leg movement (PLM), and rapid onset vasodilation (ROV). V̇O2 max was assessed with a graded exercise test on a cycle ergometer. RESULTS Indices associated with resistance artery function (e.g., peak flow during RH, PLM, and ROV) were generally related to each other (r = 0.47-77, p < .05), while indices derived from FMD were unrelated to other tests (p < .05). Absolute V̇O2 max (r = 0.57-0.73, p < .05) and mass-specific V̇O2 max (r = 0.41-0.46, p < .05) were related to indices of resistance artery function, even when controlling for factors like body mass and sex. FMD was only related to mass-specific V̇O2 max after statistically controlling for baseline artery diameter (r = 0.44, p < .05). CONCLUSION Indices of leg resistance artery function (e.g., peak flow during RH, PLM, and ROV) relate well to each other and account for ~30% of the variance in V̇O2 max not accounted for by other factors, like body mass and sex. Vascular interventions should focus on improving indices of resistance artery function, not conduit artery function, when seeking to improve exercise capacity.
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Affiliation(s)
- Jayson R. Gifford
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
- Program of GerontologyBrigham Young UniversityProvoUTUSA
| | - Brady E. Hanson
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Meagan Proffit
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
- Program of GerontologyBrigham Young UniversityProvoUTUSA
| | - Taysom Wallace
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Jason Kofoed
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Garrett Griffin
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
| | - Melina Hanson
- Department of Exercise SciencesBrigham Young UniversityProvoUTUSA
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17
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Terwoord JD, Hearon CM, Racine ML, Ketelhut NB, Luckasen GJ, Richards JC, Dinenno FA. K IR channel activation links local vasodilatation with muscle fibre recruitment during exercise in humans. J Physiol 2020; 598:2621-2636. [PMID: 32329892 DOI: 10.1113/jp279682] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 04/17/2020] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS During exercise, blood flow to working skeletal muscle increases in parallel with contractile activity such that oxygen delivery is sufficient to meet metabolic demand. K+ released from active skeletal muscle fibres could facilitate vasodilatation in proportion to the degree of muscle fibre recruitment. Once released, K+ stimulates inwardly rectifying K+ (KIR ) channels on the vasculature to elicit an increase in blood flow. In the present study, we demonstrate that KIR channels mediate the rapid vasodilatory response to an increase in exercise intensity. We also show that KIR channels augment vasodilatation during exercise which demands greater muscle fibre recruitment independent of the total amount of work performed. These results suggest that K+ plays a key role in coupling the magnitude of vasodilatation to the degree of contractile activity. Ultimately, the findings from this study help us understand the signalling mechanisms that regulate muscle blood flow in humans. ABSTRACT Blood flow to active skeletal muscle is augmented with greater muscle fibre recruitment. We tested whether activation of inwardly rectifying potassium (KIR ) channels underlies vasodilatation with elevated muscle fibre recruitment when work rate is increased (Protocol 1) or held constant (Protocol 2). We assessed forearm vascular conductance (FVC) during rhythmic handgrip exercise under control conditions and during local inhibition of KIR channels (intra-arterial BaCl2 ). In Protocol 1, healthy volunteers performed mild handgrip exercise for 3 min, then transitioned to moderate intensity for 30 s. BaCl2 eliminated vasodilatation during the first contraction at the moderate workload (ΔFVC, BaCl2 : -1 ± 17 vs. control: 30 ± 28 ml min-1 100 mmHg-1 ; n = 9; P = 0.004) and attenuated the 30 s area under the curve by 56 ± 14% (n = 9; P < 0.0001). In Protocol 2, participants performed two exercise bouts in which muscle fibre recruitment was manipulated while total contractile work was held constant via reciprocal changes in contraction frequency: (1) low fibre recruitment, with contractions at 12.5% maximal voluntary contraction once every 4 s and (2) high fibre recruitment, with contractions at 25% maximal voluntary contraction once every 8 s. Under control conditions, steady-state FVC was augmented in high vs. low fibre recruitment (211 ± 90 vs. 166 ± 73 ml min-1 ⋅100 mmHg-1 ; n = 10; P = 0.0006), whereas BaCl2 abolished the difference between high and low fibre recruitment (134 ± 59 vs. 134 ± 63 ml min-1 100 mmHg-1 ; n = 10; P = 0.85). These findings demonstrate that KIR channel activation is a key mechanism linking local vasodilatation with muscle fibre recruitment during exercise.
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Affiliation(s)
- Janée D Terwoord
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Matthew L Racine
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Nathaniel B Ketelhut
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Gary J Luckasen
- Medical Center of the Rockies Foundation, University of Colorado Health, Loveland, CO, USA
| | - Jennifer C Richards
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, USA
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18
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Limberg JK, Casey DP, Trinity JD, Nicholson WT, Wray DW, Tschakovsky ME, Green DJ, Hellsten Y, Fadel PJ, Joyner MJ, Padilla J. Assessment of resistance vessel function in human skeletal muscle: guidelines for experimental design, Doppler ultrasound, and pharmacology. Am J Physiol Heart Circ Physiol 2019; 318:H301-H325. [PMID: 31886718 DOI: 10.1152/ajpheart.00649.2019] [Citation(s) in RCA: 86] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The introduction of duplex Doppler ultrasound almost half a century ago signified a revolutionary advance in the ability to assess limb blood flow in humans. It is now widely used to assess blood flow under a variety of experimental conditions to study skeletal muscle resistance vessel function. Despite its pervasive adoption, there is substantial variability between studies in relation to experimental protocols, procedures for data analysis, and interpretation of findings. This guideline results from a collegial discussion among physiologists and pharmacologists, with the goal of providing general as well as specific recommendations regarding the conduct of human studies involving Doppler ultrasound-based measures of resistance vessel function in skeletal muscle. Indeed, the focus is on methods used to assess resistance vessel function and not upstream conduit artery function (i.e., macrovasculature), which has been expertly reviewed elsewhere. In particular, we address topics related to experimental design, data collection, and signal processing as well as review common procedures used to assess resistance vessel function, including postocclusive reactive hyperemia, passive limb movement, acute single limb exercise, and pharmacological interventions.
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Affiliation(s)
- Jacqueline K Limberg
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,François M. Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Joel D Trinity
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | | | - D Walter Wray
- Geriatric Research, Education, and Clinical Center, Veterans Affairs Medical Center, Salt Lake City, Utah.,Department of Internal Medicine, Division of Geriatrics, University of Utah, Salt Lake City, Utah.,Department of Nutrition and Integrative Physiology, University of Utah, Salt Lake City, Utah
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Daniel J Green
- School of Human Sciences (Exercise and Sport Science), University of Western Australia, Perth, Western Australia, Australia
| | - Ylva Hellsten
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Copenhagen, Denmark
| | - Paul J Fadel
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | | | - Jaume Padilla
- Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri.,Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
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19
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Lynn MJT, Mew OK, Drouin PJ, Liberman NL, Tschakovsky ME. Greater post-contraction hyperaemia below vs. above heart level: the role of active vasodilatation vs. passive mechanical distension of arterioles. J Physiol 2019; 598:85-99. [PMID: 31654419 DOI: 10.1113/jp278476] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 10/24/2019] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS The immediate increase in skeletal muscle blood flow following contraction is greater when the contracting muscle is below vs. above heart level. This has been attributed to muscle pump-mediated venous emptying and subsequent widening of the arterial to venous pressure gradient, which can occur below but not above heart level. However, alternative explanations could include greater rapid onset vasodilatation and/or transmural pressure-mediated mechanical distension of resistance vessels, but these remain unexplored. We demonstrate that active vasodilatation is not responsible for greater post-contraction hyperaemia below the heart. Instead, an increased transmural pressure-mediated mechanical distension of resistance vessels is a key mechanism responsible for this phenomenon. Our findings establish the importance of considering/accounting for local mechanical arteriolar distension effects when investigating exercise hyperaemia. They also inform the application of exercise for rehabilitative purposes and prompt investigation into whether arteriolar distension accompanying vasodilatation is reduced with diseases or ageing, thereby compromising exercising muscle perfusion. ABSTRACT We tested the hypotheses that increased post-contraction hyperaemia in higher (H; below heart) vs. lower (L; above heart) transmural pressure conditions is due to (1) greater active vasodilatation or (2) greater transmural pressure-mediated arteriolar distension. Participants (n = 20, 12 male, 8 female; combined mean age 24.5 ± 2 years) performed a 2 s isometric handgrip contraction, where arm position was maintained within or changed between H and L during contraction, resulting in four starting-finishing arm position conditions (LL, HL, LH, HH). Post-contraction forearm blood flow (echo and Doppler ultrasound) was higher with contraction release in H vs. L environments (P < 0.05). However, contraction initiated in H did not result in greater vasodilatation (forearm vascular conductance; FVC) than contraction initiated in L, regardless of contraction release condition (peak FVC: LL 217 ± 104 vs. HL 204 ± 92 ml min-1 (100 mmHg)-1 , P = 0.313, LH 229 ± 8 vs. HH 225 ± 85 ml min-1 (100 mmHg)-1 , P = 0.391; first post-contraction cardiac cycle FVC: same comparisons, both P = 0.317). However, FVC of the first post-contraction cardiac cycle was greater for contractions released in H vs. L regardless of pre-contraction condition (LL 106 ± 67 vs. LH 152 ± 76 ml min-1 (100 mmHg)-1 , P < 0.05; HL 80 ± 51 vs. HH 119 ± 58 ml min-1 (100 mmHg)-1 , P < 0.05). These findings refute the hypothesis that greater hyperaemia following a single contraction in higher transmural pressure conditions is due to greater active vasodilatation. Instead, our findings reveal a key role for increased transmural pressure-mediated mechanical distension of arterioles in creating a greater increase in vascular conductance for a given active vasodilatation following skeletal muscle contraction.
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Affiliation(s)
- Mytchel J T Lynn
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada, K7L 3N6
| | - Olivia K Mew
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada, K7L 3N6
| | - Patrick J Drouin
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada, K7L 3N6
| | - Noah L Liberman
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada, K7L 3N6
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, ON, Canada, K7L 3N6
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20
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Hurley DM, Williams ER, Cross JM, Riedinger BR, Meyer RA, Abela GS, Slade JM. Aerobic Exercise Improves Microvascular Function in Older Adults. Med Sci Sports Exerc 2019; 51:773-781. [PMID: 30489496 DOI: 10.1249/mss.0000000000001854] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Microvascular function is reduced with age, disease, and inactivity. Exercise is well known to improve vascular health and has the potential to improve microvascular function in aging and disease. PURPOSE The study aimed to assess changes in peripheral microvascular function in sedentary older adults after aerobic exercise training. METHODS Twenty-three sedentary older adults (67 ± 5 yr, body mass index = 29 ± 5, mean ± SD) successfully completed a randomized 12-wk graded treadmill walking intervention. The exercise group (EX) performed 40 min of uphill walking 4 d·wk at 70% heart rate reserve. The control group (CON) maintained a sedentary lifestyle for 12 wk. Blood oxygen level-dependent (BOLD) responses of the soleus measured by magnetic resonance imaging were used to evaluate microvascular function; brief (1 s) maximal plantarflexion contractions were performed. Separately, blood flow in the popliteal artery was measured by ultrasound after brief contraction. Phosphorus magnetic resonance spectroscopy of the calf was used to examine muscle oxidative capacity, and whole-body peak oxygen consumption (V˙O2peak) was used to confirm training-induced cardiorespiratory adaptations. RESULTS Peak postcontraction BOLD response increased by 33% in EX (PRE, 3.3% ± 1.0%; POST, 4.4% ± 1.4%) compared with CON (PRE, 3.0% ± 1.3%; POST, 3.2% ± 1.5%), P < 0.05. EX with hypertension tended to show a blunted peak BOLD increase (n = 6, 15%) compared with EX normotensive (n = 7, 50%), P = 0.056. Peak postcontraction blood flow increased by 39% in EX (PRE, 217 ± 88 mL·min; POST, 302 ± 167 mL·min) compared with CON (PRE, 188 ± 54 mL·min; POST, 184 ± 44 mL·min), P < 0.05. EX muscle oxidative capacity (kPCr) improved by 40% (PRE, 1.60 ± 0.57 min; POST, 2.25 ± 0.80 min) compared with CON (PRE, 1.69 ± 0.28 min; POST, 1.76 ± 0.52 min), P < 0.05. V˙O2peak increased by 9% for EX (PRE, 19.0 ± 3.1 mL·kg·min; POST, 20.8 ± 2.9 mL·kg·min) compared with a 7% loss in CON (PRE, 21.9 ± 3.6 mL·kg·min; POST, 20.4 ± 3.5 mL·kg·min), P < 0.05. CONCLUSION Moderate aerobic exercise significantly improved microvascular function of the leg in older adults.
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Affiliation(s)
- David M Hurley
- Department of Radiology, Michigan State University, East Lansing, MI
| | - Ewan R Williams
- Sport and Health Sciences, University of Exeter, Exeter, UNITED KINGDOM
| | - Jeff M Cross
- Department of Radiology, Michigan State University, East Lansing, MI
| | | | - Ronald A Meyer
- Department of Physiology, Michigan State University, East Lansing, MI
| | - George S Abela
- Department of Medicine, Michigan State University, East Lansing, MI
| | - Jill M Slade
- Department of Radiology, Michigan State University, East Lansing, MI
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21
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Tucker WJ, Rosenberry R, Trojacek D, Sanchez B, Bentley RF, Haykowsky MJ, Tian F, Nelson MD. Near-infrared diffuse correlation spectroscopy tracks changes in oxygen delivery and utilization during exercise with and without isolated arterial compression. Am J Physiol Regul Integr Comp Physiol 2019; 318:R81-R88. [PMID: 31746636 DOI: 10.1152/ajpregu.00212.2019] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Near-infrared diffuse correlation spectroscopy (NIR-DCS) is an emerging technology for simultaneous measurement of skeletal muscle microvascular oxygen delivery and utilization during exercise. The extent to which NIR-DCS can track acute changes in oxygen delivery and utilization has not yet been fully established. To address this knowledge gap, 14 healthy men performed rhythmic handgrip exercise at 30% maximal voluntary contraction, with and without isolated brachial artery compression, designed to acutely reduce convective oxygen delivery to the exercising muscle. Radial artery blood flow (Duplex Ultrasound) and NIR-DCS derived variables [blood flow index (BFI), tissue oxygen saturation (StO2), and metabolic rate of oxygen (MRO2)] were simultaneously measured. During exercise, both radial artery blood flow (+51.6 ± 20.3 mL/min) and DCS-derived BFI (+155.0 ± 82.2%) increased significantly (P < 0.001), whereas StO2 decreased -7.9 ± 6.2% (P = 0.002) from rest. Brachial artery compression during exercise caused a significant reduction in both radial artery blood flow (-32.0 ± 19.5 mL/min, P = 0.001) and DCS-derived BFI (-57.3 ± 51.1%, P = 0.01) and a further reduction of StO2 (-5.6 ± 3.8%, P = 0.001) compared with exercise without compression. MRO2 was not significantly reduced during arterial compression (P = 0.83) due to compensatory reductions in StO2, driven by increases in deoxyhemoglobin/myoglobin (+7.1 ± 6.1 μM, P = 0.01; an index of oxygen extraction). Together, these proof-of-concept data help to further validate NIR-DCS as an effective tool to assess the determinants of skeletal muscle oxygen consumption at the level of the microvasculature during exercise.
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Affiliation(s)
- Wesley J Tucker
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.,College of Nursing, University of Texas at Arlington, Arlington, Texas.,Department of Nutrition & Food Sciences, Texas Woman's University, Houston, Texas
| | - Ryan Rosenberry
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Darian Trojacek
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Belinda Sanchez
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas
| | - Robert F Bentley
- Faculty of Kinesiology and Physical Education, University of Toronto, Toronto, Ontario, Canada
| | - Mark J Haykowsky
- College of Nursing, University of Texas at Arlington, Arlington, Texas
| | - Fenghua Tian
- Department of Bioengineering, University of Texas at Arlington, Arlington, Texas
| | - Michael D Nelson
- Department of Kinesiology, University of Texas at Arlington, Arlington, Texas.,Department of Bioengineering, University of Texas at Arlington, Arlington, Texas
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22
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Tucker WJ, Rosenberry R, Trojacek D, Chamseddine HH, Arena-Marshall CA, Zhu Y, Wang J, Kellawan JM, Haykowsky MJ, Tian F, Nelson MD. Studies into the determinants of skeletal muscle oxygen consumption: novel insight from near-infrared diffuse correlation spectroscopy. J Physiol 2019; 597:2887-2901. [PMID: 30982990 DOI: 10.1113/jp277580] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Accepted: 04/10/2019] [Indexed: 12/12/2022] Open
Abstract
KEY POINTS Diffuse correlation spectroscopy (DCS) is emerging as a powerful tool to assess skeletal muscle perfusion. Near-infrared spectroscopy (NIRS) is an established technique for characterizing the transport and utilization of oxygen through the microcirculation. Here we compared a combined NIRS-DCS system with conventional measures of oxygen delivery and utilization during handgrip exercise. The data show good concurrent validity between convective oxygen delivery and DCS-derived blood flow index, as well as between oxygen extraction at the conduit and microvascular level. We then manipulated forearm arterial perfusion pressure by adjusting the position of the exercising arm relative to the position of the heart. The data show that microvascular perfusion can be uncoupled from convective oxygen delivery, and that tissue saturation seemingly compensates to maintain skeletal muscle oxygen consumption. Taken together, these data support a novel role for NIRS-DCS in understanding the determinants of muscle oxygen consumption at the microvascular level. ABSTRACT Diffuse correlation spectroscopy (DCS) is emerging as a powerful tool to assess skeletal muscle perfusion. Combining DCS with near-infrared spectroscopy (NIRS) introduces exciting possibilities for understanding the determinants of muscle oxygen consumption; however, no investigation has directly compared NIRS-DCS to conventional measures of oxygen delivery and utilization in an exercising limb. To address this knowledge gap, nine healthy males performed rhythmic handgrip exercise with simultaneous measurements by NIRS-DCS, Doppler blood flow and venous oxygen content. The two approaches showed good concurrent validity, with directionally similar responses between: (a) Doppler-derived forearm blood flow and DCS-derived blood flow index (BFI), and (b) venous oxygen saturation and NIRS-derived tissue saturation. To explore the utility of combined NIRS-DCS across the physiological spectrum, we manipulated forearm arterial perfusion pressure by altering the arm position above or below the level of the heart. As expected, Doppler-derived skeletal muscle blood flow increased with exercise in both arm positions, but with markedly different magnitudes (below: +424.3 ± 41.4 ml/min, above: +306 ± 12.0 ml/min, P = 0.002). In contrast, DCS-derived microvascular BFI increased to a similar extent with exercise, regardless of arm position (P = 0.65). Importantly, however, the time to reach BFI steady state was markedly slower with the arm above the heart, supporting the experimental design. Notably, we observed faster tissue desaturation at the onset of exercise with the arm above the heart, resulting in similar muscle oxygen consumption profiles throughout exercise. Taken together, these data support a novel role for NIRS-DCS in understanding the determinants of skeletal muscle oxygen utilization non-invasively and throughout exercise.
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Affiliation(s)
- Wesley J Tucker
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX, USA.,College of Nursing, University of Texas at Arlington, Arlington, TX, USA
| | - Ryan Rosenberry
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX, USA
| | - Darian Trojacek
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX, USA
| | - Houda H Chamseddine
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX, USA
| | | | - Ye Zhu
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - Jing Wang
- College of Nursing, University of Texas at Arlington, Arlington, TX, USA
| | - J Mikhail Kellawan
- Department of Health and Exercise Science, University of Oklahoma, Norman, OK, USA
| | - Mark J Haykowsky
- College of Nursing, University of Texas at Arlington, Arlington, TX, USA
| | - Fenghua Tian
- Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
| | - Michael D Nelson
- Department of Kinesiology, University of Texas at Arlington, Arlington, TX, USA.,Department of Bioengineering, University of Texas at Arlington, Arlington, TX, USA
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Mouser JG, Mattocks KT, Buckner SL, Dankel SJ, Jessee MB, Bell ZW, Abe T, Bentley JP, Loenneke JP. High-pressure blood flow restriction with very low load resistance training results in peripheral vascular adaptations similar to heavy resistance training. Physiol Meas 2019; 40:035003. [DOI: 10.1088/1361-6579/ab0d2a] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Socha MJ, Segal SS. Microvascular mechanisms limiting skeletal muscle blood flow with advancing age. J Appl Physiol (1985) 2018; 125:1851-1859. [PMID: 30412030 PMCID: PMC6737458 DOI: 10.1152/japplphysiol.00113.2018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2018] [Revised: 10/22/2018] [Accepted: 11/06/2018] [Indexed: 02/08/2023] Open
Abstract
Effective oxygen delivery to active muscle fibers requires that vasodilation initiated in distal arterioles, which control flow distribution and capillary perfusion, ascends the resistance network into proximal arterioles and feed arteries, which govern total blood flow into the muscle. With exercise onset, ascending vasodilation reflects initiation and conduction of hyperpolarization along endothelium from arterioles into feed arteries. Electrical coupling of endothelial cells to smooth muscle cells evokes the rapid component of ascending vasodilation, which is sustained by ensuing release of nitric oxide during elevated luminal shear stress. Concomitant sympathetic neural activation inhibits ascending vasodilation by stimulating α-adrenoreceptors on smooth muscle cells to constrict the resistance vasculature. We hypothesized that compromised muscle blood flow in advanced age reflects impaired ascending vasodilation through actions on both cell layers of the resistance network. In the gluteus maximus muscle of old (24 mo) vs. young (4 mo) male mice (corresponding to mid-60s vs. early 20s in humans) inhibition of α-adrenoreceptors in old mice restored ascending vasodilation, whereas even minimal activation of α-adrenoreceptors in young mice attenuated ascending vasodilation in the manner seen with aging. Conduction of hyperpolarization along the endothelium is impaired in old vs. young mice because of "leaky" membranes resulting from the activation of potassium channels by hydrogen peroxide released from endothelial cells. Exposing the endothelium of young mice to hydrogen peroxide recapitulates this effect of aging. Thus enhanced α-adrenoreceptor activation of smooth muscle in concert with electrically leaky endothelium restricts muscle blood flow by impairing ascending vasodilation in advanced age.
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Affiliation(s)
- Matthew J Socha
- Biology Department, University of Scranton , Scranton, Pennsylvania
| | - Steven S Segal
- Department of Medical Pharmacology and Physiology, University of Missouri , Columbia, Missouri
- Dalton Cardiovascular Research Center , Columbia, Missouri
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Mouser JG, Mattocks KT, Dankel SJ, Buckner SL, Jessee MB, Bell ZW, Abe T, Loenneke JP. Very-low-load resistance exercise in the upper body with and without blood flow restriction: cardiovascular outcomes. Appl Physiol Nutr Metab 2018; 44:288-292. [PMID: 30148969 DOI: 10.1139/apnm-2018-0325] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
It is proposed that, at very low loads, greater blood flow restriction (BFR) pressures might be required for muscular adaptation to occur. The cardiovascular and hyperemic response to very low loads combined with relative levels of BFR is unknown. Ninety-seven participants were recruited and assigned to 1 of 4 exercise conditions: 15% of 1-repetition maximum (1RM) without BFR (15/00), 15% 1RM with BFR at 40% of arterial occlusion pressure (AOP) (15/40), 15% of 1RM with BFR at 80% of AOP (15/80), and 70% of 1RM without BFR (70/00). Participants performed 4 sets of unilateral biceps curls. Blood pressure was measured before and after exercise; brachial artery blood flow was measured before exercise, following the second set, and 1 min following exercise. Systolic blood pressure increased following exercise in all conditions (+10 (11) mm Hg, P < 0.0005). Diastolic pressure increased in all but 70/00 (+2 (11) mm Hg, P = 0.107). Brachial artery blood flow increased following the second set of exercise in all but 15/80 (+43.4 (76.8) mL·min-1, P = 0.348). One minute following exercise and cuff deflation, there were no differences in blood flow between conditions (P > 0.05). Similarly, artery diameter was increased in all conditions except 15/80 (+0.002 (0.041) cm, P = 0.853) following the second set, and increased in all conditions by 1 min following exercise (P < 0.05). In conclusion, exercise-induced hyperemia is blunted with increasing pressures of BFR. There is a modest increase in blood pressure at very low loads of resistance exercise in the upper body.
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Affiliation(s)
- J Grant Mouser
- a Department of Kinesiology and Health Promotion, Troy University, Troy, AL 36082, USA
| | - Kevin T Mattocks
- b Department of Exercise Science, Lindenwood Belleville, Belleville, IL 62226, USA
| | - Scott J Dankel
- c Kevser Ermin Applied Physiology Laboratory, Department of Health, Exercise Science, and Recreation Management, The University of Mississippi, University, MS 38677, USA
| | - Samuel L Buckner
- d Exercise Science Program, University of South Florida, Tampa, FL 33620, USA
| | - Matthew B Jessee
- e School of Kinesiology, University of Southern Mississippi, Hattiesburg, MS 39406, USA
| | - Zachary W Bell
- c Kevser Ermin Applied Physiology Laboratory, Department of Health, Exercise Science, and Recreation Management, The University of Mississippi, University, MS 38677, USA
| | - Takashi Abe
- c Kevser Ermin Applied Physiology Laboratory, Department of Health, Exercise Science, and Recreation Management, The University of Mississippi, University, MS 38677, USA
| | - Jeremy P Loenneke
- c Kevser Ermin Applied Physiology Laboratory, Department of Health, Exercise Science, and Recreation Management, The University of Mississippi, University, MS 38677, USA
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Domingos E, Polito MD. Blood pressure response between resistance exercise with and without blood flow restriction: A systematic review and meta-analysis. Life Sci 2018; 209:122-131. [PMID: 30086274 DOI: 10.1016/j.lfs.2018.08.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2018] [Revised: 07/31/2018] [Accepted: 08/03/2018] [Indexed: 11/27/2022]
Abstract
AIM The aim of this study was to compare, by means of a systematic review and meta-analysis, the effects of resistance training with and without blood flow restriction (BFR) on blood pressure (BP). MATERIALS AND METHODS This review was composed according to the preferred Reporting items for Systematic Reviews and Meta-Analyses guidelines. Searches were carried out in the databases PubMed, SPORTDiscus, and Web of Science. BP was the main outcome for the analysis of the acute, post-exercise, and chronic effect of resistance exercise with and without BFR. Search results were limited to studies investigating the effect of resistance training with and without BFR on acute or chronic BP, published in a scientific peer-reviewed journal in English. KEY FINDINGS Seventeen references were eligible. During exercise, the diastolic BP (DBP) was higher in exercise with BFR (ES = 17.84) in comparison to traditional exercise with loads ≥60% 1RM (ES = 5.53; P < 0.01); and the systolic BP (SBP) and DBP were higher during exercise with BFR in hypertensive individuals (ES = 69.83 and 43.66) in comparison to traditional exercise with loads <60% 1RM (ES = 48.05 and 28.37; P < 0.05). In the post-exercise analysis, exercise with BFR presented lower values for SBP (ES = -5.13; P = 0.02) and DBP (ES = -4.70; P < 0.01). SIGNIFICANCE Although resistance exercise with BFR resulted in greater post-exercise hypotension than traditional exercise, higher SBP and/or DBP values were observed during exercise with BFR compared to traditional exercise, especially in hypertensive individuals. Thus, exercise with BFR should be prescribed with caution when BP control is necessary during exercise.
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Affiliation(s)
- Everton Domingos
- Research Group of Cardiovascular Response and Exercise, Londrina State University, Londrina, Paraná, PR, Brazil
| | - Marcos D Polito
- Research Group of Cardiovascular Response and Exercise, Londrina State University, Londrina, Paraná, PR, Brazil.
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Mueller PJ, Clifford PS, Crandall CG, Smith SA, Fadel PJ. Integration of Central and Peripheral Regulation of the Circulation during Exercise: Acute and Chronic Adaptations. Compr Physiol 2017; 8:103-151. [DOI: 10.1002/cphy.c160040] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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28
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Mouser JG, Laurentino GC, Dankel SJ, Buckner SL, Jessee MB, Counts BR, Mattocks KT, Loenneke JP. Blood flow in humans following low-load exercise with and without blood flow restriction. Appl Physiol Nutr Metab 2017; 42:1165-1171. [DOI: 10.1139/apnm-2017-0102] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Blood flow restriction (BFR) in combination with exercise has been used to increase muscle size and strength using relatively low loads (20%–30% 1-repetition maximum (1RM)). In research, the range of applied pressures based on a percentage of arterial occlusion pressure (AOP), is wide. The purpose of the study is to measure the blood flow response before exercise, following each set of exercise, and postexercise to low-load elbow flexion combined with no restriction (NOBFR), 40% of AOP (40BFR), and 80% of AOP (80BFR). One hundred and fifty-two participants volunteered; 140 completed the protocol (women = 75, men = 65). Participants were counter-balanced into 1 of 3 conditions. Following AOP and 1RM measurement, ultrasound was used to measure standing blood flow at rest in the right brachial artery. Participants performed 4 sets of elbow flexion at 30% 1RM. Blood flow was measured between sets and at 1 and 5 min postexercise. Blood flow decreased following inflation, with no difference between conditions (p < 0.001). Men had greater blood flow than women in all conditions at all time points (p < 0.001). Resting hyperemia decreased with pressure (NOBFR > 40BFR > 80BFR, p < 0.001). Blood flow increased from rest to after set 1 regardless of condition. Following cuff deflation, blood flow increased in both the 80BFR and 40BFR conditions. The reduction in hyperemia during BFR is pressure-dependent. Contrary to previous investigations, blood flow was increased above baseline following exercise.
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Affiliation(s)
- J. Grant Mouser
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
| | - Gilberto C. Laurentino
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
| | - Scott J. Dankel
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
| | - Samuel L. Buckner
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
| | - Matthew B. Jessee
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
| | - Brittany R. Counts
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
| | - Kevin T. Mattocks
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
| | - Jeremy P. Loenneke
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
- Department of Health, Exercise Science, and Recreation Management, Kevser Ermin Applied Physiology Laboratory, The University of Mississippi, 231 Turner Center, University, MS 38677, USA
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29
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Hughes WE, Kruse NT, Casey DP. Sympathetic nervous system activation reduces contraction-induced rapid vasodilation in the leg of humans independent of age. J Appl Physiol (1985) 2017; 123:106-115. [PMID: 28385914 DOI: 10.1152/japplphysiol.00005.2017] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Revised: 03/20/2017] [Accepted: 04/05/2017] [Indexed: 11/22/2022] Open
Abstract
Contraction-induced rapid vasodilation is attenuated similarly in the upper and lower limbs of older adults. In the forearm, this attenuation is in part due to a greater sympathetic vasoconstriction. We examined whether the age-related reduction in contraction-induced vasodilation in the leg is also due to a sympathetic vasoconstrictive mechanism. Thirteen young (24 ± 1 yr) and twelve older adults (67 ± 1 yr) performed single-leg knee extension at 20 and 40% of work-rate maximum (WRmax) during control and cold-pressor test (CPT) conditions. Femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC; ml·min-1·mmHg-1) was calculated using blood flow (ml/min) and mean arterial pressure (mmHg). Peak (ΔVC from baseline) and total VC were blunted in older adults during control conditions across exercise intensities (P < 0.05). Peak and total VC were reduced during CPT in both age groups across exercise intensities (P < 0.05). The relative change (i.e., %reduction; CPT vs. control) in peak (-25 ± 5 vs. -22 ± 4% at 20% WRmax; and -21 ± 6 vs. -27 ± 5% at 40% WRmax; P = 0.42-0.55) and total VC (-28 ± 5 vs. -36 ± 6% at 20% WRmax; and -22 ± 8 vs. -33 ± 5% at 40% WRmax; P = 0.23-0.34) were similar between young and older adults. When matched for absolute workload (~10 W), age differences persisted in peak VC (P < 0.05) under both conditions, with similar relative changes in peak and total VC during CPT. Our data suggest that 1) sympathetic stimulation reduces contraction-induced rapid vasodilation in the leg of young and older adults similarly; and 2) enhanced sympathetic vasoconstriction does not fully explain age-related differences in contraction-induced vasodilation within the leg.NEW & NOTEWORTHY Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). Within the forearm, this attenuation is partially due to enhanced sympathetic vasoconstriction. In the current study, we found that sympathetic vasoconstriction reduces contraction-induced ROV within the leg of both young and older adults, with the magnitude of change being similar between age groups. Our current results suggest that age-related attenuations in contraction-induced ROV within the leg are not fully explained by a sympathetic vasoconstrictor mechanism.
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Affiliation(s)
- William E Hughes
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Nicholas T Kruse
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa.,Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa; and
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa; .,Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa, Iowa City, Iowa; and.,Fraternal Order of Eagles Diabetes Research, Carver College of Medicine, University of Iowa, Iowa City, Iowa
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30
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Murrant CL, Lamb IR, Novielli NM. Capillary endothelial cells as coordinators of skeletal muscle blood flow during active hyperemia. Microcirculation 2017; 24. [DOI: 10.1111/micc.12348] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 12/28/2016] [Indexed: 12/13/2022]
Affiliation(s)
- Coral L. Murrant
- Department of Human Health and Nutritional Sciences; University of Guelph; Guelph ON Canada
| | - Iain R. Lamb
- Department of Human Health and Nutritional Sciences; University of Guelph; Guelph ON Canada
| | - Nicole M. Novielli
- Department of Human Health and Nutritional Sciences; University of Guelph; Guelph ON Canada
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31
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Haddock B, Holm S, Poulsen JM, Enevoldsen LH, Larsson HBW, Kjær A, Suetta C. Assessment of muscle function using hybrid PET/MRI: comparison of 18F-FDG PET and T2-weighted MRI for quantifying muscle activation in human subjects. Eur J Nucl Med Mol Imaging 2016; 44:704-711. [PMID: 27604791 PMCID: PMC5323465 DOI: 10.1007/s00259-016-3507-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Accepted: 08/29/2016] [Indexed: 12/13/2022]
Abstract
Purpose The aim of this study was to determine the relationship between relative glucose uptake and MRI T2 changes in skeletal muscles following resistance exercise using simultaneous PET/MRI scans. Methods Ten young healthy recreationally active men (age 21 – 28 years) were injected with 18F-FDG while activating the quadriceps of one leg with repeated knee extension exercises followed by hand-grip exercises for one arm. Immediately following the exercises, the subjects were scanned simultaneously with 18F-FDG PET/MRI and muscle groups were evaluated for increases in 18F-FDG uptake and MRI T2 values. Results A significant linear correlation between 18F-FDG uptake and changes in muscle T2 (R2 = 0.71) was found. for both small and large muscles and in voxel to voxel comparisons. Despite large intersubject differences in muscle recruitment, the linear correlation between 18F-FDG uptake and changes in muscle T2 did not vary among subjects. Conclusion This is the first assessment of skeletal muscle activation using hybrid PET/MRI and the first study to demonstrate a high correlation between 18F-FDG uptake and changes in muscle T2 with physical exercise. Accordingly, it seems that changes in muscle T2 may be used as a surrogate marker for glucose uptake and lead to an improved insight into the metabolic changes that occur with muscle activation. Such knowledge may lead to improved treatment strategies in patients with neuromuscular pathologies such as stroke, spinal cord injuries and muscular dystrophies.
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Affiliation(s)
- Bryan Haddock
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark.
| | - Søren Holm
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark
| | - Jákup M Poulsen
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark
| | - Lotte H Enevoldsen
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark
| | - Henrik B W Larsson
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark
| | - Andreas Kjær
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark
| | - Charlotte Suetta
- Department of Clinical Physiology, Nuclear Medicine & PET, Rigshospitalet Glostrup, Copenhagen University Hospital, Ndr. Ringvej 57, DK2600, Glostrup, Denmark
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32
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Hughes WE, Ueda K, Casey DP. Chronic endurance exercise training offsets the age-related attenuation in contraction-induced rapid vasodilation. J Appl Physiol (1985) 2016; 120:1335-42. [PMID: 27032899 DOI: 10.1152/japplphysiol.00057.2016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/25/2016] [Indexed: 01/25/2023] Open
Abstract
Aging is associated with attenuated contraction-induced rapid onset vasodilation (ROV). We sought to examine whether chronic exercise training would improve ROV in older adults. Additionally, we examined whether a relationship between cardiorespiratory fitness and ROV exists in young and older adults. Chronically exercise-trained older adults (n = 16; 66 ± 2 yr, mean ± SE) performed single muscle contractions in the forearm and leg at various intensities. Brachial and femoral artery diameter and blood velocity were measured using Doppler ultrasound. Vascular conductance (VC) was calculated as the quotient of blood flow (ml/min) and mean arterial pressure (mmHg). These data were compared with our previously published work from an identical protocol in 16 older untrained (66 ± 1 yr, mean ± SE) and 14 young (23 ± 1 yr) adults. Peak (ΔVCpeak) and total vasodilator (VCtotal) responses were greater in trained compared with untrained older adults across leg exercise intensities (P < 0.05). There were no differences in responses between trained older and young adults in the arm or leg at any exercise intensity (P > 0.05). Comparison of ΔVCpeak in a subset of subjects at an absolute workload in the leg revealed that trained older adults exhibited augmented responses relative to untrained older adults. Exercise capacity (V̇o2 peak) was associated with ΔVCpeak and VCtotal across arm (r = 0.59-0.64) and leg exercise intensities (r = 0.55-0.68, P < 0.05) in older adults. Our data demonstrate that 1) chronic exercise training improves ROV in the arm and leg of trained older adults, such that age-related differences in ROV are abolished, and 2) VO2peak is associated with ΔVCpeak responses in both limbs of older adults.
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Affiliation(s)
| | - Kenichi Ueda
- Department of Anesthesia, Carver College of Medicine, University of Iowa, Iowa City, Iowa
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science; Abboud Cardiovascular Research Center; Fraternal Order of Eagles Diabetes Research; and
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33
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Baláš J, Michailov M, Giles D, Kodejška J, Panáčková M, Fryer S. Active recovery of the finger flexors enhances intermittent handgrip performance in rock climbers. Eur J Sport Sci 2015; 16:764-72. [DOI: 10.1080/17461391.2015.1119198] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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34
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Hearon CM, Dinenno FA. Regulation of skeletal muscle blood flow during exercise in ageing humans. J Physiol 2015; 594:2261-73. [PMID: 26332887 DOI: 10.1113/jp270593] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Accepted: 08/13/2015] [Indexed: 12/12/2022] Open
Abstract
The regulation of skeletal muscle blood flow and oxygen delivery to contracting skeletal muscle is complex and involves the mechanical effects of muscle contraction; local metabolic, red blood cell and endothelium-derived substances; and the sympathetic nervous system (SNS). With advancing age in humans, skeletal muscle blood flow is typically reduced during dynamic exercise and this is due to a lower vascular conductance, which could ultimately contribute to age-associated reductions in aerobic exercise capacity, a primary predictor of mortality in both healthy and diseased ageing populations. Recent findings have highlighted the contribution of endothelium-derived substances to blood flow control in contracting muscle of older adults. With advancing age, impaired nitric oxide availability due to scavenging by reactive oxygen species, in conjunction with elevated vasoconstrictor signalling via endothelin-1, reduces the local vasodilatory response to muscle contraction. Additionally, ageing impairs the ability of contracting skeletal muscle to blunt sympathetic vasoconstriction (i.e. 'functional sympatholysis'), which is critical for the proper regulation of tissue blood flow distribution and oxygen delivery, and could further reduce skeletal muscle perfusion during high intensity and/or large muscle mass exercise in older adults. We propose that initiation of endothelium-dependent hyperpolarization is the underlying signalling event necessary to properly modulate sympathetic vasoconstriction in contracting muscle, and that age-associated impairments in red blood cell adenosine triphosphate release and stimulation of endothelium-dependent vasodilatation may explain impairments in both local vasodilatation and functional sympatholysis with advancing age in humans.
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Affiliation(s)
- Christopher M Hearon
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA
| | - Frank A Dinenno
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO, 80523, USA.,Center for Cardiovascular Research, Colorado State University, Fort Collins, CO, 80523, USA
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Hughes WE, Ueda K, Treichler DP, Casey DP. Rapid onset vasodilation with single muscle contractions in the leg: influence of age. Physiol Rep 2015; 3:3/8/e12516. [PMID: 26320213 PMCID: PMC4562596 DOI: 10.14814/phy2.12516] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The influence of aging on contraction-induced rapid vasodilation has been well characterized in the forearm. We sought to examine the impact of aging on contraction-induced rapid vasodilation in the leg following single muscle contractions and determine whether potential age-related impairments were similar between limbs (leg vs. arm). Fourteen young (23 ± 1 years) and 16 older (66 ± 1 years) adults performed single leg knee extensions at 20%, 40%, and 60% of work rate maximum. Femoral artery diameter and blood velocity were measured using Doppler ultrasound. Limb vascular conductance (VC) was calculated using blood flow (mL·min−1) and mean arterial pressure (mmHg). Peak and total vasodilator responses in the leg (change [Δ] in VC from baseline) were blunted in older adults by 44–50% across exercise intensities (P < 0.05 for all). When normalized for muscle mass, age-related differences were still evident (P < 0.05). Comparing the rapid vasodilator responses between the arm and the leg of the same individuals at similar relative intensities (20% and 40%) reveals that aging influences peak and total vasodilation equally between the limbs (no significant age × limb interaction at either intensity, P = 0.28–0.80). Our data demonstrate that (1) older adults exhibit an attenuated rapid hyperemic and vasodilator response in the leg; and (2) the age-related reductions in rapid vasodilation are similar between the arm and the leg. The mechanisms contributing to the age-related differences in contraction-induced rapid vasodilation are perhaps similar to those seen with the forearm model, but have not been confirmed.
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Affiliation(s)
- William E Hughes
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine University of Iowa, Iowa City, Iowa
| | - Kenichi Ueda
- Department of Anesthesia, Carver College of Medicine University of Iowa, Iowa City, Iowa
| | - David P Treichler
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine University of Iowa, Iowa City, Iowa
| | - Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine University of Iowa, Iowa City, Iowa
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Jasperse JL, Shoemaker JK, Gray EJ, Clifford PS. Positional differences in reactive hyperemia provide insight into initial phase of exercise hyperemia. J Appl Physiol (1985) 2015; 119:569-75. [PMID: 26139221 DOI: 10.1152/japplphysiol.01253.2013] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2013] [Accepted: 06/30/2015] [Indexed: 11/22/2022] Open
Abstract
Studies have reported a greater blood flow response to muscle contractions when the limb is below the heart compared with above the heart, and these results have been interpreted as evidence for a skeletal muscle pump contribution to exercise hyperemia. If limb position affects the blood flow response to other vascular challenges such as reactive hyperemia, this interpretation may not be correct. We hypothesized that the magnitude of reactive hyperemia would be greater with the limb below the heart. Brachial artery blood flow (Doppler ultrasound) and blood pressure (finger-cuff plethysmography) were measured in 10 healthy volunteers. Subjects lay supine with one arm supported in two different positions: above or below the heart. Reactive hyperemia was produced by occlusion of arterial inflow for varying durations: 0.5 min, 1 min, 2 min, or 5 min in randomized order. Peak increases in blood flow were 77 ± 11, 178 ± 24, 291 ± 25, and 398 ± 33 ml/min above the heart and 96 ± 19, 279 ± 62, 550 ± 60, and 711 ± 69 ml/min below the heart (P < 0.05). Thus a standard stimulus (vascular occlusion) elicited different responses depending on limb position. To determine whether these differences were due to mechanisms intrinsic to the arterial wall, a second set of experiments was performed in which acute intraluminal pressure reduction for 0.5 min, 1 min, 2 min, or 5 min was performed in isolated rat soleus feed arteries (n = 12). The magnitude of dilation upon pressure restoration was greater when acute pressure reduction occurred from 85 mmHg (mimicking pressure in the arm below the heart; 28.3 ± 7.9, 37.5 ± 5.9, 55.1 ± 9.9, and 68.9 ± 8.6% dilation) than from 48 mmHg (mimicking pressure in the arm above the heart; 20.8 ± 4.8, 22.6 ± 4.4, 31.2 ± 5.8, and 49.2 ± 7.1% dilation). These data support the hypothesis that arm position differences in reactive hyperemia are at least partially mediated by mechanisms intrinsic to the arterial wall. Overall, these results suggest the need to reevaluate studies employing positional changes to examine muscle pump influences on exercise hyperemia.
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Joyner MJ, Casey DP. Regulation of increased blood flow (hyperemia) to muscles during exercise: a hierarchy of competing physiological needs. Physiol Rev 2015; 95:549-601. [PMID: 25834232 DOI: 10.1152/physrev.00035.2013] [Citation(s) in RCA: 430] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
This review focuses on how blood flow to contracting skeletal muscles is regulated during exercise in humans. The idea is that blood flow to the contracting muscles links oxygen in the atmosphere with the contracting muscles where it is consumed. In this context, we take a top down approach and review the basics of oxygen consumption at rest and during exercise in humans, how these values change with training, and the systemic hemodynamic adaptations that support them. We highlight the very high muscle blood flow responses to exercise discovered in the 1980s. We also discuss the vasodilating factors in the contracting muscles responsible for these very high flows. Finally, the competition between demand for blood flow by contracting muscles and maximum systemic cardiac output is discussed as a potential challenge to blood pressure regulation during heavy large muscle mass or whole body exercise in humans. At this time, no one dominant dilator mechanism accounts for exercise hyperemia. Additionally, complex interactions between the sympathetic nervous system and the microcirculation facilitate high levels of systemic oxygen extraction and permit just enough sympathetic control of blood flow to contracting muscles to regulate blood pressure during large muscle mass exercise in humans.
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Affiliation(s)
- Michael J Joyner
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
| | - Darren P Casey
- Department of Anesthesiology, Mayo Clinic, Rochester, Minnesota; and Department of Physical Therapy and Rehabilitation Science, University of Iowa, Iowa City, Iowa
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Credeur DP, Holwerda SW, Restaino RM, King PM, Crutcher KL, Laughlin MH, Padilla J, Fadel PJ. Characterizing rapid-onset vasodilation to single muscle contractions in the human leg. J Appl Physiol (1985) 2014; 118:455-64. [PMID: 25539935 DOI: 10.1152/japplphysiol.00785.2014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Rapid-onset vasodilation (ROV) following single muscle contractions has been examined in the forearm of humans, but has not yet been characterized in the leg. Given known vascular differences between the arm and leg, we sought to characterize ROV following single muscle contractions in the leg. Sixteen healthy men performed random ordered single contractions at 5, 10, 20, 40, and 60% of their maximum voluntary contraction (MVC) using isometric knee extension made with the leg above and below heart level, and these were compared with single isometric contractions of the forearm (handgrip). Single thigh cuff compressions (300 mmHg) were utilized to estimate the mechanical contribution to leg ROV. Continuous blood flow was determined by duplex-Doppler ultrasound and blood pressure via finger photoplethysmography (Finometer). Single isometric knee extensor contractions produced intensity-dependent increases in peak leg vascular conductance that were significantly greater than the forearm in both the above- and below-heart level positions (e.g., above heart level: leg 20% MVC, +138 ± 28% vs. arm 20% MVC, +89 ± 17%; P < 0.05). Thigh cuff compressions also produced a significant hyperemic response, but these were brief and smaller in magnitude compared with single isometric contractions in the leg. Collectively, these data demonstrate the presence of a rapid and robust vasodilation to single muscle contractions in the leg that is largely independent of mechanical factors, thus establishing the leg as a viable model to study ROV in humans.
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Affiliation(s)
- Daniel P Credeur
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Seth W Holwerda
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Robert M Restaino
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Phillip M King
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - Kiera L Crutcher
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri
| | - M Harold Laughlin
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Department of Biomedical Sciences, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri
| | - Jaume Padilla
- Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri; Department of Nutrition and Exercise Physiology, University of Missouri, Columbia, Missouri; and Department of Child Health, University of Missouri, Columbia, Missouri
| | - Paul J Fadel
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, Missouri; Dalton Cardiovascular Research Center, University of Missouri, Columbia, Missouri;
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Bentley RF, Kellawan JM, Moynes JS, Poitras VJ, Walsh JJ, Tschakovsky ME. Individual susceptibility to hypoperfusion and reductions in exercise performance when perfusion pressure is reduced: evidence for vasodilator phenotypes. J Appl Physiol (1985) 2014; 117:392-405. [PMID: 24970851 DOI: 10.1152/japplphysiol.01155.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The primary objective of this study was to determine whether cardiovascular compensatory response phenotypes exist in the face of a reduced perfusion pressure challenge to exercising muscle oxygen delivery (O2D), and whether these responses might be exercise intensity (EI) dependent. Ten healthy men (19.5 ± 0.4 yr) completed two trials of progressive forearm isometric handgrip exercise to exhaustion (24.5 N increments every 3.5 min) in each of forearm above and below heart level [forearm arterial perfusion pressure (FAPP) difference of 29.5 ± 0.97 mmHg]. At the end of each EI, measurements of forearm blood flow (FBF; ml/min) via brachial artery Doppler and echo ultrasound, mean arterial blood pressure (MAP; mmHg) via finger photoplethysmography, and exercising forearm venous effluent via antecubital vein catheter revealed distinct cardiovascular response groups: n = 6 with compensatory vasodilation vs. n = 4 without compensatory vasodilation. Compensatory vasodilators were able to blunt the perfusion pressure-evoked reduction in submaximal O2D in the arm-above-heart condition, whereas nonvasodilators did not (-22.5 ± 13.6 vs. -65.4 ± 14.1 ml O2/min; P < 0.05), and in combination with being able to increase O2 extraction, nonvasodilators defended submaximal V̇o2 and experienced less of an accumulated submaximal O2D deficit (-80.7 ± 24.7 vs. -219.1 ± 36.0 ml O2/min; P < 0.05). As a result, the compensatory vasodilators experienced less of a compromise to peak EI than nonvasodilators (-24.5 ± 3.5 N vs. -52.1 ± 8.9 N; P < 0.05). In conclusion, in the forearm exercise model studied, vasodilatory response phenotypes exist that determine individual susceptibility to hypoperfusion and the degree to which aerobic metabolism and exercise performance are compromised.
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Affiliation(s)
- Robert F Bentley
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - J Mikhail Kellawan
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Jackie S Moynes
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Veronica J Poitras
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Jeremy J Walsh
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
| | - Michael E Tschakovsky
- School of Kinesiology and Health Studies, Queen's University, Kingston, Ontario, Canada
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Boulton D, Taylor CE, Macefield VG, Green S. Effect of contraction intensity on sympathetic nerve activity to active human skeletal muscle. Front Physiol 2014; 5:194. [PMID: 24917823 PMCID: PMC4042086 DOI: 10.3389/fphys.2014.00194] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Accepted: 05/08/2014] [Indexed: 11/20/2022] Open
Abstract
The effect of contraction intensity on muscle sympathetic nerve activity (MSNA) to active human limbs has not been established. To address this, MSNA was recorded from the left peroneal nerve during and after dorsiflexion contractions sustained for 2 min by the left leg at ~10, 25, and 40% MVC. To explore the involvement of the muscle metaboreflex, limb ischemia was imposed midway during three additional contractions and maintained during recovery. Compared with total MSNA at rest (11.5 ± 4.1 mv.min−1), MSNA in the active leg increased significantly at the low (21.9 ± 13.6 mv.min−1), medium (30.5 ± 20.8 mv.min−1), and high (50.0 ± 24.5 mv.min−1) intensities. This intensity-dependent effect was more strongly associated with increases in MSNA burst amplitude than burst frequency. Total MSNA then returned to resting levels within the first minute of recovery. Limb ischemia had no significant influence on the intensity-dependent rise in MSNA or its decline during recovery in the active leg. These findings reveal intensity-dependent increases in total MSNA and burst amplitude to contracting human skeletal muscle that do not appear to involve the muscle metaboreflex.
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Affiliation(s)
- Daniel Boulton
- School of Science and Health, University of Western Sydney Sydney, NSW, Australia
| | - Chloe E Taylor
- School of Science and Health, University of Western Sydney Sydney, NSW, Australia
| | - Vaughan G Macefield
- School of Medicine, University of Western Sydney Sydney, NSW, Australia ; Neuroscience Research Australia Sydney, NSW, Australia
| | - Simon Green
- School of Science and Health, University of Western Sydney Sydney, NSW, Australia ; School of Medicine, University of Western Sydney Sydney, NSW, Australia ; Neuroscience Research Australia Sydney, NSW, Australia
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Novielli NM, Jackson DN. Contraction-evoked vasodilation and functional hyperaemia are compromised in branching skeletal muscle arterioles of young pre-diabetic mice. Acta Physiol (Oxf) 2014; 211:371-84. [PMID: 24703586 DOI: 10.1111/apha.12297] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2013] [Revised: 12/14/2013] [Accepted: 03/28/2014] [Indexed: 12/25/2022]
Abstract
AIM To investigate the effects of pre-diabetes on microvascular network function in contracting skeletal muscle. We hypothesized that pre-diabetes compromises contraction-evoked vasodilation of branching second-order (2A), third-order (3A) and fourth-order (4A) arterioles, where distal arterioles would be affected the greatest. METHODS Intravital video microscopy was used to measure arteriolar diameter (in 2A, 3A and 4A) and blood flow (in 2A and 3A) changes to electrical field stimulation of the gluteus maximus muscle in pre-diabetic (The Pound Mouse, PD) and control (c57bl6, CTRL) mice. RESULTS Baseline diameter and blood flow were similar between groups (2A: ~20 μm, 3A: ~14 μm and 4A: ~8 μm; 2A: ~1 nL s(-1) and 3A: ~0.5 nL s(-1) ). Single tetanic contraction (100 Hz; 200, 400, 800 ms duration) evoked rapid-onset vasodilation (ROV) and blood flow responses that were blunted by ~50% and up to 81%, respectively, in PD vs. CTRL (P < 0.05). The magnitude of ROV was up to 2-fold greater at distal arterioles (3A and 4A) vs. proximal arterioles (2A) in CTRL; however, in PD, ROV of only 4A was greater than 2A (P < 0.05). Rhythmic contraction (2 and 8 Hz, 30 s) evoked vasodilatory and blood flow responses that were also attenuated by ~50% and up to 71%, respectively, in PD vs. CTRL (P < 0.05). The magnitude of vasodilatory responses to rhythmic contraction was also up to 2.5-fold greater at 4A vs. 2A in CTRL; however spatial differences in vasodilation across arteriolar branch orders was disrupted in PD. CONCLUSIONS Arteriolar dysregulation in pre-diabetes causes deficits in contraction-evoked dilation and blood flow, where greatest deficits occur at distal arterioles.
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Affiliation(s)
- N. M. Novielli
- Department of Medical Biophysics; Western University; London ON Canada
| | - D. N. Jackson
- Department of Medical Biophysics; Western University; London ON Canada
- Biomedical Engineering Graduate Program; Western University; London ON Canada
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Abstract
Muscular exercise requires transitions to and from metabolic rates often exceeding an order of magnitude above resting and places prodigious demands on the oxidative machinery and O2-transport pathway. The science of kinetics seeks to characterize the dynamic profiles of the respiratory, cardiovascular, and muscular systems and their integration to resolve the essential control mechanisms of muscle energetics and oxidative function: a goal not feasible using the steady-state response. Essential features of the O2 uptake (VO2) kinetics response are highly conserved across the animal kingdom. For a given metabolic demand, fast VO2 kinetics mandates a smaller O2 deficit, less substrate-level phosphorylation and high exercise tolerance. By the same token, slow VO2 kinetics incurs a high O2 deficit, presents a greater challenge to homeostasis and presages poor exercise tolerance. Compelling evidence supports that, in healthy individuals walking, running, or cycling upright, VO2 kinetics control resides within the exercising muscle(s) and is therefore not dependent upon, or limited by, upstream O2-transport systems. However, disease, aging, and other imposed constraints may redistribute VO2 kinetics control more proximally within the O2-transport system. Greater understanding of VO2 kinetics control and, in particular, its relation to the plasticity of the O2-transport/utilization system is considered important for improving the human condition, not just in athletic populations, but crucially for patients suffering from pathologically slowed VO2 kinetics as well as the burgeoning elderly population.
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Affiliation(s)
- David C Poole
- Departments of Kinesiology, Anatomy, and Physiology, Kansas State University, Manhattan, Kansas, USA.
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Abstract
The activities of daily living typically occur at metabolic rates below the maximum rate of aerobic energy production. Such activity is characteristic of the nonsteady state, where energy demands, and consequential physiological responses, are in constant flux. The dynamics of the integrated physiological processes during these activities determine the degree to which exercise can be supported through rates of O₂ utilization and CO₂ clearance appropriate for their demands and, as such, provide a physiological framework for the notion of exercise intensity. The rate at which O₂ exchange responds to meet the changing energy demands of exercise--its kinetics--is dependent on the ability of the pulmonary, circulatory, and muscle bioenergetic systems to respond appropriately. Slow response kinetics in pulmonary O₂ uptake predispose toward a greater necessity for substrate-level energy supply, processes that are limited in their capacity, challenge system homeostasis and hence contribute to exercise intolerance. This review provides a physiological systems perspective of pulmonary gas exchange kinetics: from an integrative view on the control of muscle oxygen consumption kinetics to the dissociation of cellular respiration from its pulmonary expression by the circulatory dynamics and the gas capacitance of the lungs, blood, and tissues. The intensity dependence of gas exchange kinetics is discussed in relation to constant, intermittent, and ramped work rate changes. The influence of heterogeneity in the kinetic matching of O₂ delivery to utilization is presented in reference to exercise tolerance in endurance-trained athletes, the elderly, and patients with chronic heart or lung disease.
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Affiliation(s)
- Harry B Rossiter
- Institute of Membrane and Systems Biology, University of Leeds, Leeds, United Kingdom.
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Casey DP, Walker BG, Ranadive SM, Taylor JL, Joyner MJ. Contribution of nitric oxide in the contraction-induced rapid vasodilation in young and older adults. J Appl Physiol (1985) 2013; 115:446-55. [PMID: 23788575 DOI: 10.1152/japplphysiol.00446.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that reduced nitric oxide (NO) bioavailability contributes to the attenuated peak and total vasodilation following single-muscle contractions in older adults. Young (n = 10; 24 ± 2 yr) and older (n = 10; 67 ± 2 yr) adults performed single forearm contractions at 10, 20, and 40% of maximum during saline infusion (control) and NO synthase (NOS) inhibition via N(G)-monomethyl-l-arginine. Brachial artery diameters and velocities were measured using Doppler ultrasound and forearm vascular conductance (FVC; in ml·min(-1)·100 mmHg(-1)) was calculated from blood flow (ml/min) and blood pressure (mmHg). Peak and total vasodilator responses [change (Δ) in FVC from baseline] were attenuated in older adults at all intensities (P < 0.05). NOS inhibition reduced the peak ΔFVC at 10% (88 ± 12 vs. 52 ± 9 ml·min(-1)·100 mmHg(-1)), 20% (125 ± 13 vs. 83 ± 13 ml·min(-1)·100 mmHg(-1)), and 40% (207 ± 26 vs. 133 ± 20 ml·min(-1)·100 mmHg(-1)) in young subjects, (P < 0.05 for all) and in older adults at 10% (59 ± 5 vs. 47 ± 7 ml·min(-1)·100 mmHg(-1), P < 0.05) and 20% (88 ± 9 vs. 68 ± 9 ml·min(-1)·100 mmHg(-1), P < 0.05), but not 40% (128 ± 12 vs. 105 ± 11 ml·min(-1)·100 mmHg(-1), P = 0.11). The relative (%) reduction in peak ΔFVC due to NOS inhibition was greater in young vs. older adults at 20% (-36 ± 5 vs. -23 ± 5%, P < 0.05) and 40% (-35 ± 6 vs. -16 ± 7%, P < 0.05). The reduction in the total vasodilator response (area under the curve) with NOS inhibition was also greater in young vs. older adults at all intensities. Our data suggest that contraction-induced rapid vasodilation is mediated in part by NO, and that the contribution of NO is greater in young adults.
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Affiliation(s)
- Darren P Casey
- Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
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Crecelius AR, Kirby BS, Luckasen GJ, Larson DG, Dinenno FA. Mechanisms of rapid vasodilation after a brief contraction in human skeletal muscle. Am J Physiol Heart Circ Physiol 2013; 305:H29-40. [PMID: 23645465 DOI: 10.1152/ajpheart.00298.2013] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
A monophasic increase in skeletal muscle blood flow is observed after a brief single forearm contraction in humans, yet the underlying vascular signaling pathways remain largely undetermined. Evidence from experimental animals indicates an obligatory role of vasodilation via K⁺-mediated smooth muscle hyperpolarization, and human data suggest little to no independent role for nitric oxide (NO) or vasodilating prostaglandins (PGs). We tested the hypothesis that K⁺-mediated vascular hyperpolarization underlies the rapid vasodilation in humans and that combined inhibition of NO and PGs would have a minimal effect on this response. We measured forearm blood flow (Doppler ultrasound) and calculated vascular conductance 10 s before and for 30 s after a single 1-s dynamic forearm contraction at 10%, 20%, and 40% maximum voluntary contraction in 16 young adults. To inhibit K⁺-mediated vasodilation, BaCl₂ and ouabain were infused intra-arterially to inhibit inwardly rectifying K⁺ channels and Na⁺-K⁺-ATPase, respectively. Combined enzymatic inhibition of NO and PG synthesis occurred via NG-monomethyl-L-arginine (L-NMMA; NO synthase) and ketorolac (cyclooxygenase), respectively. In protocol 1 (n = 8), BaCl₂ + ouabain reduced peak vasodilation (range: 30-45%, P < 0.05) and total postcontraction vasodilation (area under the curve, ~55-75% from control) at all intensities. Contrary to our hypothesis, L-NMMA + ketorolac had a further impact (peak: ~60% and area under the curve: ~80% from control). In protocol 2 (n = 8), the order of inhibitors was reversed, and the findings were remarkably similar. We conclude that K⁺-mediated hyperpolarization and NO and PGs, in combination, significantly contribute to contraction-induced rapid vasodilation and that inhibition of these signaling pathways nearly abolishes this phenomenon in humans.
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Affiliation(s)
- Anne R Crecelius
- Human Cardiovascular Physiology Laboratory, Department of Health and Exercise Science, Colorado State University, Fort Collins, CO 80523, USA
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Ross GA, Mihok ML, Murrant CL. Extracellular adenosine initiates rapid arteriolar vasodilation induced by a single skeletal muscle contraction in hamster cremaster muscle. Acta Physiol (Oxf) 2013; 208:74-87. [PMID: 23297742 DOI: 10.1111/apha.12060] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2012] [Revised: 12/18/2012] [Accepted: 12/21/2012] [Indexed: 11/29/2022]
Abstract
AIM Recent studies suggest that adenosine (ADO) can be produced extracellularly in response to skeletal muscle contraction. We tested the hypothesis that a single muscle contraction produces extracellular ADO rapidly enough and in physiologically relevant concentrations to be able to contribute to the rapid vasodilation that occurs at the onset of muscle contraction. METHODS We stimulated four to five skeletal muscle fibres in the anaesthetized hamster cremaster preparation in situ and measured the change in diameter of arterioles at a site of overlap with the stimulated muscle fibres before and after a single contraction (stimulus frequencies: 4, 20 and 60 Hz; 250 ms train duration). Muscle fibres were stimulated in the absence and presence of non-specific ADO membrane receptor antagonists 8-phenyltheophylline (8-PT, 10(-6) M) or xanthine amine congener (XAC, 10(-6) M) or an inhibitor of an extracellular source of ADO, ecto-5'-nucleotidase inhibitor α,β-methylene adenosine 5'-diphosphate (AMPCP, 10(-5) M). RESULTS We observed that the dilatory event at 4 s following a single contraction was significantly inhibited at all stimulus frequencies by an average of 63.9 ± 2.6% by 8-PT. The 20-s dilatory event that occurred at 20 and 60 Hz was significantly inhibited by 53.6 ± 2.6 and 73.8 ± 2.3% by 8-PT and XAC respectively. Further, both the 4- and 20-s dilatory events were significantly inhibited by AMPCP by 78.6 ± 6.6 and 67.1 ± 1.5%, respectively, at each stimulus frequency tested. CONCLUSIONS Our data show that ADO is produced extracellularly during a single muscle contraction and that it is produced rapidly enough and in physiologically relevant concentrations to contribute to the rapid vasodilation in response to muscle contraction.
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Affiliation(s)
- G. A. Ross
- Department of Human Biology and Nutritional Science; University of Guelph; Guelph; ON; Canada
| | - M. L. Mihok
- Department of Human Biology and Nutritional Science; University of Guelph; Guelph; ON; Canada
| | - C. L. Murrant
- Department of Human Biology and Nutritional Science; University of Guelph; Guelph; ON; Canada
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Murias JM, Spencer MD, Keir DA, Paterson DH. Systemic and vastus lateralis muscle blood flow and O2 extraction during ramp incremental cycle exercise. Am J Physiol Regul Integr Comp Physiol 2013; 304:R720-5. [PMID: 23515617 DOI: 10.1152/ajpregu.00016.2013] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
During ramp incremental cycling exercise increases in pulmonary O2 uptake (Vo2p) are matched by a linear increase in systemic cardiac output (Q). However, it has been suggested that blood flow in the active muscle microvasculature does not display similar linearity in blood flow relative to metabolic demand. This study simultaneously examined both systemic and regional (microvascular) blood flow and O2 extraction during incremental cycling exercise. Ten young men (Vo2 peak = 4.2 ± 0.5 l/min) and 10 young women (Vo2 peak = 3.2 ± 0.5 l/min) were recruited to perform two maximal incremental cycling tests on separate days. The acetylene open-circuit technique and mass spectrometry and volume turbine were used to measure Q (every minute) and breath-by-breath Vo2p, respectively; systemic arterio-venous O2 difference (a-vO2diff) was calculated as Vo2p/Q on a minute-by-minute basis. Changes in near-infrared spectroscopy-derived muscle deoxygenation (Δ[HHb]) were used (in combination with Vo2p data) to estimate the profiles of peripheral O2 extraction and blood flow of the active muscle microvasculature. The systemic Q-to-Vo2p relationship was linear (~5.8 l/min increase in Q for a 1 l/min increase in Vo2p) with a-vO2diff displaying a hyperbolic response as exercise intensity increased toward Vo2 peak. The peripheral blood flow response profile was described by an inverted sigmoid curve, indicating nonlinear responses relative to metabolic demand. The Δ[HHb] profile increased linearly with absolute Vo2p until high-intensity exercise, thereafter displaying a "near-plateau". Results indicate that systemic blood flow and thus O2 delivery does not reflect the profile of blood flow changes at the level of the microvasculature.
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Affiliation(s)
- Juan M Murias
- Canadian Centre for Activity and Aging, School of Kinesiology, University of Western Ontario, London, Ontario, Canada
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Casey DP, Joyner MJ. Influence of α-adrenergic vasoconstriction on the blunted skeletal muscle contraction-induced rapid vasodilation with aging. J Appl Physiol (1985) 2012; 113:1201-12. [PMID: 22961267 DOI: 10.1152/japplphysiol.00734.2012] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
We tested the hypothesis that elevated sympathetic tone is responsible for lower peak vasodilation after single muscle contractions in older adults. Young (n = 13, 7 men and 6 women, age: 27 ± 1 yr) and older (n = 13, 7 men and 6 women, age: 69 ± 2 yr) adults performed single forearm contractions at 10%, 20%, and 40% of maximum during 1) control, 2) sympathetic activation via lower body negative pressure (LBNP; -20 mmHg), and 3) intra-arterial infusion of phentolamine (α-adrenergic antagonist). Brachial artery diameter and velocities were measured via Doppler ultrasound, and forearm vascular conductance (FVC; in ml·min(-1)·100 mmHg(-1)) was calculated from blood flow (in ml/min) and blood pressure (in mmHg). Peak vasodilator responses [change in (Δ) FVC from baseline] were attenuated in older adults at 20% and 40% of maximum (P < 0.05). LBNP reduced peak ΔFVC at 10% (98 ± 17 vs. 70 ± 12 ml·min(-1)·100 mmHg(-1)), 20% (144 ± 12 vs. 98 ± 3 ml·min(-1)·100 mmHg(-1)), and 40% (209 ± 20 vs. 161 ± 21 ml·min(-1)·100 mmHg(-1), P < 0.01 vs. control) in younger adults but not in older adults (71 ± 11 vs. 68 ± 11, 107 ± 13 vs. 106 ± 16, and 161 ± 22 vs. 144 ± 22 ml·min(-1)·100 mmHg(-1), respectively, P = 0.22-0.99). With phentolamine, peak ΔFVC was enhanced in older adults at each contraction intensity (100 ± 14, 147 ± 22, and 200 ± 26 ml·min(-1)·100 mmHg(-1), respectively, P < 0.01 vs. control) but not in younger adults (94 ± 13, 153 ± 13, and 224 ± 27 ml·min(-1)·100 mmHg(-1), respectively, P = 0.30-0.81 vs. control). Our data indicate that α-adrenergic vasoconstriction and/or blunted functional sympatholysis might contribute to the age-related decreases in skeletal muscle contraction-induced rapid vasodilation in humans.
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Affiliation(s)
- Darren P Casey
- Department of Anesthesiology, Mayo Clinic, 200 First Street SW, Rochester, MN 55905, USA.
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Blain GM, Limberg JK, Mortensen GF, Schrage WG. Rapid onset vasodilatation is blunted in obese humans. Acta Physiol (Oxf) 2012; 205:103-12. [PMID: 21981828 DOI: 10.1111/j.1748-1716.2011.02370.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIM Conduit artery function in obese humans is frequently assessed at rest, but very little is known about resistance artery function in response to muscle contraction. We tested the hypothesis that obese adults will exhibit reduced contraction-induced rapid onset vasodilatation. Single and brief forearm contractions were used to isolate the local effects of muscle contraction on the forearm vasodilatory response, independent of systemic haemodynamic and sympathetic neural influence. METHODS We measured forearm blood flow (Doppler ultrasound), blood pressure (finger photoplethysmography) and heart rate (electrocardiogram) on a beat-by-beat basis in 14 obese (body mass index = 36.2 ± 1.7 kg m(-2)) and 14 lean (body mass index = 21.6 ± 0.7 kg m(-2)) young (18-40 years) adults. Percent changes from baseline in forearm vascular conductance (FVC(%) ) were calculated in response to single, brief forearm contractions performed in random order at 15, 20, 25, 30, 40 and 50% of maximal voluntary contraction (MVC). RESULTS In both groups, each single contraction evoked a significant (P < 0.05), immediate (within one cardiac cycle) and graded FVC(%) increase from one up to six cardiac cycles post-contraction. Immediate (20-50% MVC), peak (15-50% MVC) and total (area under the curve, 20-50% MVC) vasodilatory responses were reduced with obesity. The degree of impaired vasodilatation increased with increasing workloads. CONCLUSIONS These novel findings demonstrate a blunted contraction-induced rapid onset vasodilatation with obesity that is exercise intensity dependent. Impaired rapid onset vasodilatation may negatively impact haemodynamic responses to everyday intermittent activities performed by obese humans.
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Affiliation(s)
- G M Blain
- Department of Population Health Sciences, The John Rankin Laboratory of Pulmonary Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, USA
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Reeder EJ, Green S. Dynamic response characteristics of hyperaemia in the human calf muscle: effect of exercise intensity and relation to electromyographic activity. Eur J Appl Physiol 2012; 112:3997-4013. [DOI: 10.1007/s00421-012-2362-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2011] [Accepted: 02/17/2012] [Indexed: 11/29/2022]
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