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Exercise pressor response

Nicholas T Kruse, Kenichi Ueda, William E Hughes, Darren P Casey
Peripheral arterial disease (PAD) is characterized by a reduced blood flow (BF) and elevated blood pressure (pressor) response during lower extremity exercise. Although PAD is evident in the upper extremities no studies have determined BF and pressor responses during upper extremity exercise in PAD. Emerging evidence suggests that inorganic nitrate (NO3 ) supplementation may serve as an alternative dietary strategy to boost nitric oxide bioavailability, improving exercising BF and pressor responses during exercise...
March 9, 2018: American Journal of Physiology. Heart and Circulatory Physiology
Derek C Monroe, Jianchun Yin, Kevin K McCully, Rodney K Dishman
Context • Hypotension that occurs after a single bout of aerobic exercise also attenuates the vascular response to discrete stressors, an effect that can last for hours. It is unknown whether the hypotensive benefits of traditional exercise extend to alternative forms of mindful exercise, such as yoga, to confer transient protection against neurovascular challenges that increase blood pressure (BP). Objectives • The study intended to examine the effects of acute exercise on neurovascular responses to exposure of the forehead of female yoga practitioners to vasoconstrictive cold (ie, to cold pressor stress)...
February 24, 2018: Alternative Therapies in Health and Medicine
Jonathan E Harms, Audrey J Stone, Marc P Kaufman
Patients with peripheral artery disease show an exaggerated pressor response to mild exercise, an effect attributable to the exercise pressor reflex, whose afferent arm is comprised of the thinly myelinated group III and unmyelinated group IV afferents. Previously, we found that DAMGO, a μ opioid agonist injected into the femoral artery, attenuated the exaggerated exercise pressor reflex in rats with ligated femoral arteries, a preparation which simulates the blood flow patterns to muscle that is seen in patients with PAD...
February 21, 2018: Journal of Neurophysiology
Jihong Xing, Jian Lu, Jiahao Liu, Jianhua Li
The exercise pressor reflex is amplified in patients with peripheral artery disease (PAD) and in an experimental PAD model of rats induced by femoral artery occlusion. Heightened blood pressure worsens the restricted blood flow directed to the limbs in this disease. The purpose of this study was to determine the role played by muscle oxidative stress in regulating the augmented pressor response to static exercise in PAD. We hypothesized that limb ischemia impairs muscle superoxide dismutase (SOD) thereby leading to abnormal autonomic responsiveness observed in PAD animals, and a chronic compensation of SOD for anti-oxidation improves the exaggerated exercise pressor reflex...
2018: Frontiers in Physiology
Juan A Estrada, Marc P Kaufman
Mu opioid G-protein coupled receptors (MOR) interact with ion channels to decrease neuronal excitability. In humans, intrathecal administration of the MOR agonist, fentanyl, inhibits the exercise pressor reflex, an effect that can be attributed to either the opening of inward rectifying potassium channels (GIRK) or the closing of N-type calcium channels. The purpose of this study was to determine if the highly selective MOR agonist DAMGO attenuates the exercise pressor reflex, and which of these two channels are responsible for this effect...
January 17, 2018: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Wioletta Pijacka, Pedro L Katayama, Helio C Salgado, Gisele S Lincevicius, Ruy R Campos, Fiona D McBryde, Julian F R Paton
The carotid body has recently emerged as a promising therapeutic target for treating cardiovascular disease, however the potential impact of carotid bodies removal on the dynamic cardiovascular responses to acute stressors such as exercise, hypoxia and hypercapnia in hypertension is an important safety consideration that has not been studied. We first validated a novel surgical approach to selectively resect the carotid bodies bilaterally (CBR) sparing the carotid sinus baroreflex. Second, we evaluated the impact of CBR on the cardiovascular responses to exercise, hypoxia and hypercapnia in the conscious, chronically instrumented spontaneously hypertensive (SH) rats...
January 5, 2018: Journal of Physiology
Hanna R Parmar, Jasmin Sears, Yannick Molgat-Seon, Cara L McCulloch, Laura A McCracken, Courtney V Brown, Andrew William Sheel, Paolo B Dominelli
There are known sex-differences in blood pressure regulation. The differences are related to ovarian hormones that influence β-adrenergic receptors and the transduction of muscle sympathetic nerve activity. Oral contraceptives (OC) modulate the ovarian hormonal profile in women and therefore may alter the cardiovascular response. We questioned if OC would alter the absolute pressor response to static exercise and influence the day-to-day variability of the response. Healthy men (n=11) and women (n=19) completed a familiarization day and two experimental testing days...
December 5, 2017: Applied Physiology, Nutrition, and Metabolism, Physiologie Appliquée, Nutrition et Métabolisme
Karambir Notay, Jordan B Lee, Anthony V Incognito, Jeremy D Seed, Adam A Arthurs, Philip J Millar
PURPOSE: Whether differences in absolute muscle strength impact blood pressure (BP) responses to relative intensity static exercise remains controversial but could contribute to known sex-based differences and influence the interpretation of cross-sectional data. METHODS: One hundred thirty-two healthy participants (66 men and 66 women, age: 22±3yrs) underwent continuous seated measurements of BP (Finometer) and heart rate (electrocardiography) during baseline rest and two minutes of static handgrip (30% maximal voluntary contraction [MVC])...
November 10, 2017: Medicine and Science in Sports and Exercise
Jihong Xing, Jianhua Li
BACKGROUND/AIMS: Limb ischemia occurs in peripheral artery disease (PAD). Sympathetic nerve activity (SNA) that regulates blood flow directed to the ischemic limb is exaggerated during exercise in this disease, and transient receptor potential channel A1 (TRPA1) in thin-fiber muscle afferents contributes to the amplified sympathetic response. The purpose of the present study was to determine the role of proteinase-activated receptor-2 (PAR2) in regulating abnormal TRPA1 function and the TRPA1-mediated sympathetic component of the exercise pressor reflex...
2017: Cellular Physiology and Biochemistry
Masashi Ichinose, Mayumi Matsumoto, Naoto Fujii, Narumi Yoshitake, Takeshi Nishiyasu
Voluntary apnea during dynamic exercise evokes marked bradycardia, peripheral vasoconstriction and pressor responses. However, the mechanism(s) underlying the cardiovascular responses seen during apnea in exercising humans is unknown. We therefore tested the hypothesis that the muscle metaboreflex contributes to the apnea-induced pressor response during dynamic exercise. Thirteen healthy subjects participated in apnea and control trials. In both trials, subjects performed a two-legged dynamic knee extension exercise at a workload that elicited heart rates around 100 beats/min...
November 3, 2017: American Journal of Physiology. Heart and Circulatory Physiology
Evan A Kempf, Korynne S Rollins, Tyler D Hopkins, Alec L Butenas, Joseph M Santin, Joshua R Smith, Steven W Copp
Mechanical and metabolic signals arising during skeletal muscle contraction reflexly increase sympathetic nerve activity and blood pressure (i.e., the exercise pressor reflex). In a rat model of simulated peripheral artery disease (PAD) in which a femoral artery is chronically (~72 hours) ligated, the mechanically-sensitive component of the exercise pressor reflex during 1 Hz dynamic contraction is exaggerated compared to that found in normal rats. Whether this is due to an enhanced acute sensitization of mechanoreceptors by metabolites produced during contraction or involves a chronic sensitization of mechanoreceptors is unknown...
October 20, 2017: American Journal of Physiology. Heart and Circulatory Physiology
J Matthew Kuczmarski, Kellee Unrath, Gail D Thomas
Patients with atherosclerotic peripheral artery disease (PAD) have an augmented pressor response to treadmill walking, but the underlying mechanisms remain poorly understood and difficult to isolate due to the confounding presence of numerous cardiovascular risk factors. In this study, we tested the hypothesis that a chronic deficit in muscle blood flow capacity would be sufficient to trigger an exaggerated pressor response to dynamic exercise. Sprague Dawley rats (5 male, 5 female) were instrumented with radiotelemetery devices in order to measure the cardiovascular responses to treadmill running before and after bilateral femoral artery ligation, which has been shown previously to reduce the blood flow capacity of the distal hindlimb muscles by >60%...
October 6, 2017: American Journal of Physiology. Heart and Circulatory Physiology
Jasdeep Kaur, Danielle Senador, Abhinav C Krishnan, Hanna W Hanna, Alberto Alvarez, Tiago M Machado, Donal S O'Leary
When oxygen delivery to active muscle is insufficient to meet the metabolic demand during exercise, metabolites accumulate and stimulate skeletal muscle afferents inducing a reflex increase in blood pressure, termed the muscle metaboreflex. In healthy individuals, muscle metaboreflex activation (MMA) during submaximal exercise increases arterial pressure primarily via an increase in cardiac output (CO), as little peripheral vasoconstriction occurs. This increase in CO partially restores blood flow to ischemic muscle...
September 22, 2017: American Journal of Physiology. Heart and Circulatory Physiology
Pramita Dubey, Sunita Tiwari, Manish Bajpai, Kalpana Singh, Praveen Jha
INTRODUCTION: Metaboreflex is a reflex in which muscle receptors send signals regarding metabolic (metabolites accumulation like lactic acid, potassium, adenosine) conditions of the muscles to nucleus tractus solitarius via afferent III and IV fibres to cause haemodynamic adjustments in order to regulate blood flow on the basis of the status of contracting muscle. Dysregulation in its mechanism in metabolic syndrome is demonstrated. AIM: To study the effect of metaboreflex by both isometric and rhythmic handgrip exercise on CVS parameters {Blood Pressure (BP), Cardiac Output (CO) and Systemic Vascular Resistance (SVR)} in subjects of metabolic syndrome...
July 2017: Journal of Clinical and Diagnostic Research: JCDR
Gaetano A Lanza, Monica Filice, Antonio De Vita, Angelo Villano, Laura Manfredonia, Priscilla Lamendola, Filippo Crea
BACKGROUND: A sizeable proportion of patients with primary stable microvascular angina (MVA; exercise-induced angina, positive exercise stress test [EST], normal coronary arteries) have recurrent symptoms during follow-up. There have been no previous studies, however, on the long-term results of EST and their correlation with symptom outcome.Methods and Results:Follow-up EST was performed in 71 MVA patients at an average of 16.2 years (range, 5-25 years) from the first EST. Angina status was assessed on weekly frequency of angina episodes and nitroglycerin consumption and by whether symptoms had worsened, improved, or remained unchanged over time...
September 9, 2017: Circulation Journal: Official Journal of the Japanese Circulation Society
Victoria L Meah, Karianne Backx, Margie H Davenport
In the general population, functional haemodynamic testing, such as submaximal aerobic exercise, isometric handgrip, and the cold pressor test, has long been utilised to unmask abnormalities in cardiovascular function. During pregnancy, functional haemodynamic testing places additional demands on an already stressed maternal cardiovascular system. Dysfunctional responses to such tests in early pregnancy may predict the development of hypertensive disorders that develop later in gestation. These recommendations cover a description, an overview of the current understanding of clinical application, test protocol, equipment and considerations of each of the above functional haemodynamic tests during pregnancy...
August 30, 2017: Ultrasound in Obstetrics & Gynecology
Rachel C Drew
Cardiovascular adjustments to exercise resulting in increased blood pressure (BP) and heart rate (HR) occur in response to activation of several neural mechanisms: the exercise pressor reflex, central command, and the arterial baroreflex. Neural inputs from these feedback and feedforward mechanisms integrate in the cardiovascular control centers in the brain stem and modulate sympathetic and parasympathetic neural outflow, resulting in the increased BP and HR observed during exercise. Another specific consequence of the central neural integration of these inputs during exercise is increased sympathetic neural outflow directed to the kidneys, causing renal vasoconstriction, a key reflex mechanism involved in blood flow redistribution during increased skeletal muscle work...
December 1, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Justin D Sprick, Caroline A Rickards
Remote ischemic preconditioning (RIPC) is characterized by the cyclical application of limb blood flow restriction and reperfusion and has been shown to protect vital organs during a subsequent ischemic insult. Blood flow restriction exercise (BFRE) similarly combines bouts of blood flow restriction with low-intensity exercise and thus could potentially emulate the protection demonstrated by RIPC. One concern with BFRE, however, is the potential for an augmented rise in sympathetic outflow due to greater activation of the exercise pressor reflex...
November 1, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Justin D Sprick, Caroline A Rickards
Remote ischemic preconditioning (RIPC) can attenuate tissue damage sustained by ischemia-reperfusion injury. Blood flow restriction exercise (BFRE) restricts blood flow to exercising muscles. We implemented a novel approach to BFRE with cyclical bouts of blood flow restriction-reperfusion, reflecting the RIPC model. A concern about BFRE, however, is potential amplification of the exercise pressor reflex, which could be unsafe in at-risk populations. We hypothesized that cyclical BFRE would elicit greater increases in sympathetic outflow and arterial pressure than conventional exercise (CE) when performed at the same relative intensity...
November 1, 2017: American Journal of Physiology. Regulatory, Integrative and Comparative Physiology
Antonio Crisafulli
Hemodynamics during dynamic exercise is finely regulated by some neural mechanisms. One of these mechanisms is the metabolic part of the exercise pressor reflex, i.e. the muscle metaboreflex. Hemodynamic response during the metaboreflex is characterised by the recruitment of the reserves in cardiac inotropism, pre-load, after-load and chronotropism. If one of these reserves is exhausted, then the cardiovascular response is achieved by recruiting one of the other reserves, thereby indicating a remarkable plasticity of the control of circulation...
August 4, 2017: Current Cardiology Reviews
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