| Beta1-adrenoceptor mediated origin of the heart rate performance curve deflection. | |
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MedLine Citation:
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PMID: 16260969 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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PURPOSE: The deflection of the HR performance curve (HRPC) has been described as an objective marker of submaximal exercise performance. HR response to incremental cycle ergometer exercise is shown to be neither linear nor uniform and a physiological explanation of the deflection phenomenon is lacking. We hypothesized that differences in the beta1-adrenoceptor site are the source of these differences. The aim of the study was to investigate the influence of the highly selective beta1-adrenoceptor (beta1-AR) antagonist bisoprolol (Bi) on the HRPC in young healthy male subjects with different HR response patterns. METHODS: Sixteen subjects were treated in randomized order with Bi or a placebo (Pl) in two separate trials. HR response during incremental cycle ergometer exercise was compared between the two trials. Blood lactate concentration (La) and ventilatory variables were measured throughout both tests. RESULTS: Bi changed the direction of the HRPC more in subjects with a regular, s-shaped response pattern under placebo than those with a nonregular or linear pattern. The influence of Bi on the HR at the second lactate turn point was significantly related (R = 0.78; P < 0.001) to the pattern of the HRPC in Pl conditions. CONCLUSION: We suggest that differences between the subjects with regular s-shaped versus nonregular HRPC may be due to differences at the beta1-AR site. The origin of the HRPC deflection is mediated in part by the beta1-AR sensitivity. |
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Authors:
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Peter Hofmann; Manfred Wonisch; Rochus Pokan; Günther Schwaberger; Gerhard Smekal; Serge P von Duvillard |
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Publication Detail:
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Type: Journal Article; Randomized Controlled Trial |
Journal Detail:
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Title: Medicine and science in sports and exercise Volume: 37 ISSN: 0195-9131 ISO Abbreviation: Med Sci Sports Exerc Publication Date: 2005 Oct |
Date Detail:
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Created Date: 2005-11-01 Completed Date: 2006-01-17 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8005433 Medline TA: Med Sci Sports Exerc Country: United States |
Other Details:
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Languages: eng Pagination: 1704-9 Citation Subset: IM; S |
Affiliation:
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Institute of Sports Science, University of Graz, Graz, Austria. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic beta-Antagonists
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pharmacology* Adult Bisoprolol / pharmacology* Exercise Test Heart Rate / drug effects, physiology* Humans Lactates / blood Male Oxygen Consumption / drug effects Receptors, Adrenergic, beta-1 / physiology* |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic beta-Antagonists; 0/Lactates; 0/Receptors, Adrenergic, beta-1; 66722-44-9/Bisoprolol |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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