Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
SHR Neuro Krebs Kardio Lipid Stoffw Microb
Hofmann, P; Wonisch, M; Pokan, R; Schwaberger, G; Smekal, G; von Duvillard, SP.
Beta1-adrenoceptor mediated origin of the heart rate performance curve deflection.
Med Sci Sports Exerc. 2005; 37(10):1704-1709
Doi: 10.1249/01.mss.0000176308.40316.cc
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PubMed
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- Co-Autor*innen der Med Uni Graz
- Schwaberger Guenther
- Wonisch Manfred
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- Abstract:
- 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.
- Find related publications in this database (using NLM MeSH Indexing)
- Adrenergic beta-Antagonists - pharmacology
- Adult - pharmacology
- Bisoprolol - pharmacology
- Exercise Test - pharmacology
- Heart Rate - drug effects
- Humans - drug effects
- Lactates - blood
- Male - blood
- Oxygen Consumption - drug effects
- Receptors, Adrenergic, beta-1 - physiology
- Find related publications in this database (Keywords)
- lactate turn point
- HR turn point
- beta(1)-adrenoceptor antagonist
- cycle ergometer exercise