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Hirofumi Tanaka - One of the best experts on this subject based on the ideXlab platform.
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impact of leg Blood Flow restriction during walking on central arterial hemodynamics
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2015Co-Authors: Jun Sugawara, Tsubasa Tomoto, Hirofumi TanakaAbstract:Walking exercise with Limb Blood Flow restriction (BFR) has been shown to increase muscular mass and strength even if it is performed at low exercise intensities. Despite mounting evidence for its efficacy and the increasing popularity, the safety of BFR exercise in relation to cardiac loads has not been established. The aim of this study was to determine the response of central hemodynamics during the BFR exercise to assess its impact on cardiac load. Fifteen apparently healthy sedentary or recreationally active adults (10 men and 5 women, 27 ± 1 yr) underwent five bouts of 2-min constant treadmill walking at 2 mph with 1-min rest intervals either with or without BFR on both proximal thighs. Beat-by-beat Blood pressure and hemodynamics (via ModelFlow method) were measured, and central arterial hemodynamics were evaluated with pulse wave analyses via general transfer function. Incident wave amplitude (IWA) and reflected wave amplitude (RWA) were obtained by the wave separation analysis. Peripheral systolic Blood pressure (SBP) increased more substantially during walking with BFR (43 ± 5% vs. baseline) than without BFR (11 ± 4% vs. baseline). Aortic SBP did not change significantly during walking without BFR, but there was a substantial elevation in aortic SBP (43 ± 5% vs. baseline) during walking with BFR. Significant effect of BFR was seen in IWA but not in RWA. These findings suggest that even during slow-speed walking, leg BFR induces substantial hypertensive responses in the aorta. However, this response could not be explained by the augmented wave reflection.
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muscle spasticity associated with reduced whole leg perfusion in persons with spinal cord injury
Journal of Spinal Cord Medicine, 2011Co-Authors: Mandeep Dhindsa, Hirofumi Tanaka, Curtis A Merring, Lauren E Brandt, Lisa GriffinAbstract:Objective To determine the association between peripheral Blood Flow and spasticity in individuals with spinal cord injury (SCI). Design A cross-sectional study with measurements of muscle spasticity and whole-Limb Blood Flow in individuals with SCI. Setting University of Texas at Austin and Brain & Spine Recovery Center, Austin, TX, USA. Participants Eighteen individuals (14 males and 4 females) with SCI were classified into high (N = 7), low (N = 6), and no (N = 5) spasticity groups according to the spasticity levels determined by the modified Ashworth scale scores. Interventions Whole-Limb Blood Flow was measured in the femoral and brachial arteries using Doppler ultrasound and was normalized to lean Limb mass obtained with dual-energy X-ray absorptiometry. Outcome measures Limb Blood Flow and muscle spasticity. Results Age, time post-SCI, and the American Spinal Injury Association impairment scale motor and sensory scores were not different among groups with different muscle spasticity. Femoral artery...
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effects of leg Blood Flow restriction during walking on cardiovascular function
Medicine and Science in Sports and Exercise, 2010Co-Authors: Christopher P Renzi, Hirofumi Tanaka, Jun SugawaraAbstract:Introduction—Exercise with Limb Blood Flow restriction (BFR) is a very popular exercise modality in Japan and is spreading widely to the rest of the world. The underlying principle of this training modality is that under the conditions of restricted Blood Flow, even low-intensity exercise can provide significant muscle strength and hypertrophy. One concern, however, is that BFR during exercise may place unnecessary burden on those with compromised cardiac function. Methods—We determined the impact of leg BFR during walking on cardiovascular function in 17 young (26±1 years) healthy volunteers. Each subject underwent five bouts of 2-minute treadmill walking at 2 miles/hour with 1-min interval either with or without tourniquet cuffs inflated on both thighs. Results—Heart rate increased more during the BFR session, whereas stroke volume decreased greater during the BFR session. Blood pressure increased significantly and substantially during the BFR session. Consequently, an increase in double product, an index of myocardial oxygen demand, was >3-fold higher in the BFR condition. Systemic arterial compliance evaluated by stroke volume/pulse pressure ratio significantly increased during the control session by 14% but reduced during the BFR condition by 19%. Popliteal artery Flow-mediated vasodilation decreased significantly after the exercise with BFR but not after the control session.
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resistance training increases basal Limb Blood Flow and vascular conductance in aging humans
Journal of Applied Physiology, 2006Co-Authors: Maria M Anton, Miriam Y Cortezcooper, Allison E Devan, Daria B Neidre, Jill N Cook, Hirofumi TanakaAbstract:Age-related reductions in basal Limb Blood Flow and vascular conductance are associated with the metabolic syndrome, functional impairments, and osteoporosis. We tested the hypothesis that a streng...
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reductions in basal Limb Blood Flow and lumen diameter after short term leg casting
Medicine and Science in Sports and Exercise, 2004Co-Authors: Jun Sugawara, Koichiro Hayashi, Fuminari Kaneko, Hiroshi Yamada, Tomohiro Kizuka, Hirofumi TanakaAbstract:Purpose: We tested the hypotheses that short-term casting immobilization of a leg would reduce basal Blood Flow and vascular conductance and induces structural alterations in femoral artery. Methods: Right knee and ankle joints of eight healthy young men were immobilized with casting for 7 d. Before and immediately after casting, and 14 d after the cast was removed, femoral artery hemodynamics and structure were measured using a high-resolution ultrasound. Results: Femoral artery lumen diameter in the immobilized leg decreased after the immobilization (P < 0.05) and returned to baseline during the recovery period, in which the subjects did not receive any special rehabilitation treatment. Femoral artery intima-media thickness (IMT) and IMT/lumen ratio in both legs did not show significant changes throughout the interventions. In the immobilized leg, femoral artery Blood Flow and vascular conductance decreased (-23 to 24%) after the immobilization (all P < 0.05). These parameters returned to the baseline during the recovery period, and there were no significant differences between the baseline and recovery values. In the control leg, femoral Blood Flow and vascular conductance did not change throughout the investigation. After 7 d of casting, femoral arterial distension, an index of arterial distensibility, tended to decrease in the immobilized leg but not in the control leg. Conclusion: We concluded that a short-term immobilization of lower Limb decreases basal Limb Blood Flow and arterial lumen diameter. These results suggest that basal Limb Blood Flow and lumen diameter decrease rapidly upon the cessation of muscular weight bearing and locomotor activity, and may be modulated by an ordinary level of physical activity.
Bruno T. Roseguini - One of the best experts on this subject based on the ideXlab platform.
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thermotherapy reduces Blood pressure and circulating endothelin 1 concentration and enhances leg Blood Flow in patients with symptomatic peripheral artery disease
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2016Co-Authors: Dustin Neff, Alisha M. Kuhlenhoelter, Brett J. Wong, Raghu L. Motaganahalli, Bruno T. RoseguiniAbstract:Leg thermotherapy (TT) application reduces Blood pressure (BP) and increases both Limb Blood Flow and circulating levels of anti-inflammatory mediators in healthy, young humans and animals. The pur...
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Thermotherapy reduces Blood pressure and circulating endothelin-1 concentration and enhances leg Blood Flow in patients with symptomatic peripheral artery disease
American journal of physiology. Regulatory integrative and comparative physiology, 2016Co-Authors: Dustin Neff, Alisha M. Kuhlenhoelter, Chen Lin, Brett J. Wong, Raghu L. Motaganahalli, Bruno T. RoseguiniAbstract:Leg thermotherapy (TT) application reduces Blood pressure (BP) and increases both Limb Blood Flow and circulating levels of anti-inflammatory mediators in healthy, young humans and animals. The purpose of the present study was to determine the impact of TT application using a water-circulating garment on leg and systemic hemodynamics and on the concentrations of circulating cytokines and vasoactive mediators in patients with symptomatic peripheral artery disease (PAD). Sixteen patients with PAD and intermittent claudication (age: 63 ± 9 yr) completed three experimental sessions in a randomized order: TT, control intervention, and one exercise testing session. The garment was perfused with 48°C water for 90 min in the TT session and with 33°C water in the control intervention. A subset of 10 patients also underwent a protocol for the measurement of Blood Flow in the popliteal artery during 90 min of TT using phase-contrast MRI. Compared with the control intervention, TT promoted a significant reduction in systolic (∼11 mmHg) and diastolic (∼6 mmHg) BP (P < 0.05) that persisted for nearly 2 h after the end of the treatment. The serum concentration of endothelin-1 (ET-1) was significantly lower 30 min after exposure to TT (Control: 2.3 ± 0.1 vs. TT: 1.9 ± 0.09 pg/ml, P = 0.026). In addition, TT induced a marked increase in peak Blood Flow velocity (∼68%), average velocity (∼76%), and average Blood Flow (∼102%) in the popliteal artery (P < 0.01). These findings indicate that TT is a practical and effective strategy to reduce BP and circulating ET-1 concentration and enhance leg Blood Flow in patients with PAD.
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inspiratory muscle training improves Blood Flow to resting and exercising Limbs in patients with chronic heart failure
Journal of the American College of Cardiology, 2008Co-Authors: Gaspar R Chiappa, Bruno T. Roseguini, Paulo J C Vieira, Cristiano N Alves, Angela Tavares, Eliane Roseli Winkelmann, Elton L Ferlin, Ricardo Stein, Jorge P RibeiroAbstract:Objectives We tested the hypothesis that inspiratory muscle loading could result in exaggerated peripheral vasoconstriction in resting and exercising Limbs and that inspiratory muscle training (IMT) could attenuate this effect in patients with chronic heart failure (CHF) and inspiratory muscle weakness. Background Inspiratory muscle training improves functional capacity of patients with CHF, but the mechanisms of this effect are unknown. Methods Eighteen patients with CHF and inspiratory muscle weakness (maximal inspiratory pressure Results With inspiratory muscle loading, CHF patients demonstrated a more marked reduction in resting CBF and showed an attenuated rise in exercising FBF when compared with control subjects. After 4 weeks of IMT, CHF patients presented hypertrophy of the diaphragm and improved resting CBF and exercise FBF with inspiratory muscle loading. Conclusions In patients with CHF and inspiratory muscle weakness, inspiratory muscle loading results in marked reduction of Blood Flow to resting and exercising Limbs. Inspiratory muscle training improves Limb Blood Flow under inspiratory loading in these patients.
Jun Sugawara - One of the best experts on this subject based on the ideXlab platform.
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impact of leg Blood Flow restriction during walking on central arterial hemodynamics
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2015Co-Authors: Jun Sugawara, Tsubasa Tomoto, Hirofumi TanakaAbstract:Walking exercise with Limb Blood Flow restriction (BFR) has been shown to increase muscular mass and strength even if it is performed at low exercise intensities. Despite mounting evidence for its efficacy and the increasing popularity, the safety of BFR exercise in relation to cardiac loads has not been established. The aim of this study was to determine the response of central hemodynamics during the BFR exercise to assess its impact on cardiac load. Fifteen apparently healthy sedentary or recreationally active adults (10 men and 5 women, 27 ± 1 yr) underwent five bouts of 2-min constant treadmill walking at 2 mph with 1-min rest intervals either with or without BFR on both proximal thighs. Beat-by-beat Blood pressure and hemodynamics (via ModelFlow method) were measured, and central arterial hemodynamics were evaluated with pulse wave analyses via general transfer function. Incident wave amplitude (IWA) and reflected wave amplitude (RWA) were obtained by the wave separation analysis. Peripheral systolic Blood pressure (SBP) increased more substantially during walking with BFR (43 ± 5% vs. baseline) than without BFR (11 ± 4% vs. baseline). Aortic SBP did not change significantly during walking without BFR, but there was a substantial elevation in aortic SBP (43 ± 5% vs. baseline) during walking with BFR. Significant effect of BFR was seen in IWA but not in RWA. These findings suggest that even during slow-speed walking, leg BFR induces substantial hypertensive responses in the aorta. However, this response could not be explained by the augmented wave reflection.
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effects of leg Blood Flow restriction during walking on cardiovascular function
Medicine and Science in Sports and Exercise, 2010Co-Authors: Christopher P Renzi, Hirofumi Tanaka, Jun SugawaraAbstract:Introduction—Exercise with Limb Blood Flow restriction (BFR) is a very popular exercise modality in Japan and is spreading widely to the rest of the world. The underlying principle of this training modality is that under the conditions of restricted Blood Flow, even low-intensity exercise can provide significant muscle strength and hypertrophy. One concern, however, is that BFR during exercise may place unnecessary burden on those with compromised cardiac function. Methods—We determined the impact of leg BFR during walking on cardiovascular function in 17 young (26±1 years) healthy volunteers. Each subject underwent five bouts of 2-minute treadmill walking at 2 miles/hour with 1-min interval either with or without tourniquet cuffs inflated on both thighs. Results—Heart rate increased more during the BFR session, whereas stroke volume decreased greater during the BFR session. Blood pressure increased significantly and substantially during the BFR session. Consequently, an increase in double product, an index of myocardial oxygen demand, was >3-fold higher in the BFR condition. Systemic arterial compliance evaluated by stroke volume/pulse pressure ratio significantly increased during the control session by 14% but reduced during the BFR condition by 19%. Popliteal artery Flow-mediated vasodilation decreased significantly after the exercise with BFR but not after the control session.
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reductions in basal Limb Blood Flow and lumen diameter after short term leg casting
Medicine and Science in Sports and Exercise, 2004Co-Authors: Jun Sugawara, Koichiro Hayashi, Fuminari Kaneko, Hiroshi Yamada, Tomohiro Kizuka, Hirofumi TanakaAbstract:Purpose: We tested the hypotheses that short-term casting immobilization of a leg would reduce basal Blood Flow and vascular conductance and induces structural alterations in femoral artery. Methods: Right knee and ankle joints of eight healthy young men were immobilized with casting for 7 d. Before and immediately after casting, and 14 d after the cast was removed, femoral artery hemodynamics and structure were measured using a high-resolution ultrasound. Results: Femoral artery lumen diameter in the immobilized leg decreased after the immobilization (P < 0.05) and returned to baseline during the recovery period, in which the subjects did not receive any special rehabilitation treatment. Femoral artery intima-media thickness (IMT) and IMT/lumen ratio in both legs did not show significant changes throughout the interventions. In the immobilized leg, femoral artery Blood Flow and vascular conductance decreased (-23 to 24%) after the immobilization (all P < 0.05). These parameters returned to the baseline during the recovery period, and there were no significant differences between the baseline and recovery values. In the control leg, femoral Blood Flow and vascular conductance did not change throughout the investigation. After 7 d of casting, femoral arterial distension, an index of arterial distensibility, tended to decrease in the immobilized leg but not in the control leg. Conclusion: We concluded that a short-term immobilization of lower Limb decreases basal Limb Blood Flow and arterial lumen diameter. These results suggest that basal Limb Blood Flow and lumen diameter decrease rapidly upon the cessation of muscular weight bearing and locomotor activity, and may be modulated by an ordinary level of physical activity.
Daniel J Green - One of the best experts on this subject based on the ideXlab platform.
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assessment of resistance vessel function in human skeletal muscle guidelines for experimental design doppler ultrasound and pharmacology
American Journal of Physiology-heart and Circulatory Physiology, 2020Co-Authors: Jacqueline K Limberg, Joel D. Trinity, Darren P. Casey, Daniel J Green, Wayne T Nicholson, Walter D Wray, Michael E Tschakovsky, Ylva Hellsten, Paul J Fadel, Michael J JoynerAbstract: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 f...
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cold water mediates greater reductions in Limb Blood Flow than whole body cryotherapy
Medicine and Science in Sports and Exercise, 2017Co-Authors: Chris Mawhinney, Helen Jones, David A Low, Daniel J Green, Joseph T Costello, Warren GregsonAbstract:PURPOSE: Cold-water immersion (CWI) and whole body cryotherapy (WBC) are widely used recovery methods in an attempt to limit exercise-induced muscle damage, soreness and functional deficits after strenuous exercise. The aim of this study was to compare the effects of ecologically-valid CWI and WBC protocols on post-exercise lower Limb thermoregulatory, femoral artery and cutaneous Blood Flow responses. METHODS: Ten males completed a continuous cycle exercise protocol at 70% maximal oxygen uptake until a rectal temperature of 38°C was attained. Participants were then exposed to lower-body CWI (8°C) for 10 min, or WBC (-110°C) for 2 min, in a randomized cross-over design. Rectal and thigh skin, deep and superficial muscle temperatures, thigh and calf skin Blood Flow (laser Doppler Flowmetry), superficial femoral artery Blood Flow (duplex ultrasound) and arterial Blood pressure were measured prior to, and for 40 min post, cooling interventions. RESULTS: Greater reductions in thigh skin (CWI, -5.9±1.8°C; WBC, 0.2±0.5°C; P < 0.001) and superficial (CWI, -4.4±1.3°C; WBC, -1.8±1.1°C; P < 0.001) and deep (CWI, -2.9±0.8°C; WBC, -1.3±0.6°C; P < 0.001) muscle temperatures occurred immediately after CWI. Decreases in femoral artery conductance were greater after CWI (CWI, -84±11%; WBC, -59±21%, P < 0.02) and thigh (CWI, -80±5%; WBC, -59±14%, P < 0.001) and calf (CWI, -73±13%; WBC, -45±17%, P < 0.001) cutaneous vasoconstriction was greater following CWI. Reductions in rectal temperature were similar between conditions after cooling (CWI, -0.6±0.4°C; WBC, -0.6±0.3°C; P = 0.98). CONCLUSION: Greater reductions in Blood Flow and tissue temperature were observed after CWI in comparison to WBC. These novel findings have practical and clinical implications for the use of cooling in the recovery from exercise and injury.
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influence of cold water immersion on Limb Blood Flow after resistance exercise
European Journal of Sport Science, 2017Co-Authors: Chris Mawhinney, Helen Jones, David A Low, Daniel J Green, Glyn Howatson, Warren GregsonAbstract:AbstractThis study determined the influence of cold (8°C) and cool (22°C) water immersion on lower Limb and cutaneous Blood Flow following resistance exercise. Twelve males completed 4 sets of 10-repetition maximum squat exercise and were then immersed, semi-reclined, into 8°C or 22°C water for 10-min, or rested in a seated position (control) in a randomized order on different days. Rectal and thigh skin temperature, muscle temperature, thigh and calf skin Blood Flow and superficial femoral artery Blood Flow were measured before and after immersion. Indices of vascular conductance were calculated (flux and Blood Flow/mean arterial pressure). The colder water reduced thigh skin temperature and deep muscle temperature to the greatest extent (P < .001). Reductions in rectal temperature were similar (0.2–0.4°C) in all three trials (P = .69). Femoral artery conductance was similar after immersion in both cooling conditions, with both conditions significantly lower (55%) than the control post-immersion (P < .01...
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influence of cold water immersion on Limb and cutaneous Blood Flow at rest
American Journal of Sports Medicine, 2011Co-Authors: Warren Gregson, Helen Jones, Mark A Black, Jordon Milson, James P Morton, Brian Dawson, Greg Atkinson, Daniel J GreenAbstract:Background: Cold water immersion reduces exercise-induced muscle damage. Benefits may partly arise from a decline in Limb Blood Flow; however, no study has comprehensively investigated the influence of different degrees of cooling undertaken via cold water immersion on Limb Blood Flow responses.Purpose: To determine the influence of cold (8°C) and cool (22°C) water immersion on lower Limb and cutaneous Blood Flow.Study Design: Controlled laboratory study.Methods: Nine men were placed in a semireclined position and lowered into 8°C or 22°C water to the iliac crest for two 5-minute periods interspersed with 2 minutes of nonimmersion. Rectal and thigh skin temperature, deep and superficial muscle temperature, heart rate, mean arterial pressure, thigh cutaneous Blood velocity (laser Doppler), and superficial femoral artery Blood Flow (duplex ultrasound) were measured during immersion and for 30 minutes after immersion. Indices of vascular conductance were calculated (flux and Blood Flow/mean arterial pressure...
Dustin Neff - One of the best experts on this subject based on the ideXlab platform.
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thermotherapy reduces Blood pressure and circulating endothelin 1 concentration and enhances leg Blood Flow in patients with symptomatic peripheral artery disease
American Journal of Physiology-regulatory Integrative and Comparative Physiology, 2016Co-Authors: Dustin Neff, Alisha M. Kuhlenhoelter, Brett J. Wong, Raghu L. Motaganahalli, Bruno T. RoseguiniAbstract:Leg thermotherapy (TT) application reduces Blood pressure (BP) and increases both Limb Blood Flow and circulating levels of anti-inflammatory mediators in healthy, young humans and animals. The pur...
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Thermotherapy reduces Blood pressure and circulating endothelin-1 concentration and enhances leg Blood Flow in patients with symptomatic peripheral artery disease
American journal of physiology. Regulatory integrative and comparative physiology, 2016Co-Authors: Dustin Neff, Alisha M. Kuhlenhoelter, Chen Lin, Brett J. Wong, Raghu L. Motaganahalli, Bruno T. RoseguiniAbstract:Leg thermotherapy (TT) application reduces Blood pressure (BP) and increases both Limb Blood Flow and circulating levels of anti-inflammatory mediators in healthy, young humans and animals. The purpose of the present study was to determine the impact of TT application using a water-circulating garment on leg and systemic hemodynamics and on the concentrations of circulating cytokines and vasoactive mediators in patients with symptomatic peripheral artery disease (PAD). Sixteen patients with PAD and intermittent claudication (age: 63 ± 9 yr) completed three experimental sessions in a randomized order: TT, control intervention, and one exercise testing session. The garment was perfused with 48°C water for 90 min in the TT session and with 33°C water in the control intervention. A subset of 10 patients also underwent a protocol for the measurement of Blood Flow in the popliteal artery during 90 min of TT using phase-contrast MRI. Compared with the control intervention, TT promoted a significant reduction in systolic (∼11 mmHg) and diastolic (∼6 mmHg) BP (P < 0.05) that persisted for nearly 2 h after the end of the treatment. The serum concentration of endothelin-1 (ET-1) was significantly lower 30 min after exposure to TT (Control: 2.3 ± 0.1 vs. TT: 1.9 ± 0.09 pg/ml, P = 0.026). In addition, TT induced a marked increase in peak Blood Flow velocity (∼68%), average velocity (∼76%), and average Blood Flow (∼102%) in the popliteal artery (P < 0.01). These findings indicate that TT is a practical and effective strategy to reduce BP and circulating ET-1 concentration and enhance leg Blood Flow in patients with PAD.