Document Detail


Beta-adrenergic blockade and metabo-chemoreflex contributions to exercise capacity.
MedLine Citation:
PMID:  18845967     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
PURPOSE: Exercise-induced dyspnea in patients with cardiopulmonary diseases may be related to sympathetic nervous system activation, with increased metabo- and/or chemosensitivities. Whether this mechanism plays a role in exercising normal subjects remains unclear. METHODS: Muscle sympathetic nerve activity (MSNA), HR, ventilation (V(E)), O2 saturation (SpO2), and end-tidal PCO2 (PetCO2) were measured in 14 healthy young adults after 1 wk of beta1-receptor blockade with bisoprolol 5 mg x d(-1) versus placebo after a double-blind, placebo-controlled, randomized crossover design. The MSNA and the ventilatory responses to hyperoxic hypercapnia (7% CO2 in O2), DeltaV(E)/DeltaPetCO2, and isocapnic hypoxia (10% O2 in N2), DeltaV(E)/DeltaSpO2, and to an isometric muscle contraction followed by a local circulatory arrest (metaboreflex) were determined at rest followed by an incremental cardiopulmonary exercise test. RESULTS: Bisoprolol did not change the V(E) and MSNA responses to hypercapnia, hyperoxia, or isometric muscle contraction or ischemia. Bisoprolol decreased maximum O2 uptake (P < 0.05), workload (P < 0.05), and HR (P < 0.0001) and both V(E)/VO2 and V(E)/VCO2 slopes (P < 0.05). CONCLUSIONS: These results suggest that decreased aerobic exercise capacity after intake of beta-blockers is accompanied by decreased ventilation at any metabolic rate. However, this occurs without detectable change in the sympathetic nervous system tone or in metabo- or chemosensitivity and is therefore probably of hemodynamic origin.
Authors:
Sofia Beloka; Marko Gujic; Gael Deboeck; Georges Niset; Agnieszka Ciarka; Jean-François Argacha; Dionysios Adamopoulos; Philippe Van de Borne; Robert Naeije
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Publication Detail:
Type:  Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  40     ISSN:  1530-0315     ISO Abbreviation:  Med Sci Sports Exerc     Publication Date:  2008 Nov 
Date Detail:
Created Date:  2009-05-12     Completed Date:  2009-07-06     Revised Date:  2009-07-13    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1932-8     Citation Subset:  IM; S    
Affiliation:
Department of Cardiology, Erasme Hospital, Brussels, Belgium.
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MeSH Terms
Descriptor/Qualifier:
Adolescent
Adrenergic beta-Antagonists / pharmacology*
Adult
Cross-Over Studies
Double-Blind Method
Exercise / physiology*
Hemodynamics / drug effects*
Humans
Male
Muscle, Skeletal / drug effects*,  metabolism
Oxygen Consumption
Placebos
Sympathetic Nervous System / drug effects*
Young Adult
Chemical
Reg. No./Substance:
0/Adrenergic beta-Antagonists; 0/Placebos
Comments/Corrections
Comment In:
Med Sci Sports Exerc. 2009 Apr;41(4):967; author reply 968   [PMID:  19300143 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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