| Cerebral oxygenation decreases during exercise in humans with beta-adrenergic blockade. | |
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MedLine Citation:
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PMID: 19053964 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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AIM: Beta-blockers reduce exercise capacity by attenuated increase in cardiac output, but it remains unknown whether performance also relates to attenuated cerebral oxygenation. METHODS: Acting as their own controls, eight healthy subjects performed a continuous incremental cycle test to exhaustion with or without administration of the non-selective beta-blocker propranolol. Changes in cerebral blood flow velocity were measured with transcranial Doppler ultrasound and those in cerebral oxygenation were evaluated using near-infrared spectroscopy and the calculated cerebral mitochondrial oxygen tension derived from arterial to internal jugular venous concentration differences. RESULTS: Arterial lactate and cardiac output increased to 15.3 +/- 4.2 mM and 20.8 +/- 1.5 L min(-1) respectively (mean +/- SD). Frontal lobe oxygenation remained unaffected but the calculated cerebral mitochondrial oxygen tension decreased by 29 +/- 7 mmHg (P < 0.05). Propranolol reduced resting heart rate (58 +/- 6 vs. 69 +/- 8 beats min(-1)) and at exercise exhaustion, cardiac output (16.6 +/- 3.6 L min(-1)) and arterial lactate (9.4 +/- 3.7 mM) were attenuated with a reduction in exercise capacity from 239 +/- 42 to 209 +/- 31 W (all P < 0.05). Propranolol also attenuated the increase in cerebral blood flow velocity and frontal lobe oxygenation (P < 0.05) whereas the cerebral mitochondrial oxygen tension decreased to a similar degree as during control exercise (delta 28 +/- 10 mmHg; P < 0.05). CONCLUSION: Propranolol attenuated the increase in cardiac output of consequence for cerebral perfusion and oxygenation. We suggest that a decrease in cerebral oxygenation limits exercise capacity. |
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Authors:
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T Seifert; P Rasmussen; N H Secher; H B Nielsen |
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Publication Detail:
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Type: Controlled Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't Date: 2008-11-28 |
Journal Detail:
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Title: Acta physiologica (Oxford, England) Volume: 196 ISSN: 1748-1716 ISO Abbreviation: Acta Physiol (Oxf) Publication Date: 2009 Jul |
Date Detail:
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Created Date: 2009-06-16 Completed Date: 2010-06-22 Revised Date: 2012-03-08 |
Medline Journal Info:
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Nlm Unique ID: 101262545 Medline TA: Acta Physiol (Oxf) Country: England |
Other Details:
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Languages: eng Pagination: 295-302 Citation Subset: IM |
Affiliation:
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Department of Anaesthesia, The Copenhagen Muscle Research Centre, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark. tseifert78@gmail.com |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adrenergic beta-Antagonists
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pharmacology* Adult Blood Pressure / drug effects, physiology Brain / blood supply, drug effects, metabolism* Carbon Dioxide / blood Cardiac Output / drug effects, physiology Cerebrovascular Circulation / drug effects, physiology Exercise / physiology* Exercise Test Exercise Tolerance / drug effects, physiology Frontal Lobe / blood supply, drug effects, metabolism Heart Rate / drug effects, physiology Humans Male Mitochondria / metabolism Oxygen / blood, metabolism* Partial Pressure Propranolol / pharmacology Young Adult |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic beta-Antagonists; 124-38-9/Carbon Dioxide; 525-66-6/Propranolol; 7782-44-7/Oxygen |
| Comments/Corrections | |
Comment In:
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Acta Physiol (Oxf). 2009 Jul;196(3):279-81
[PMID:
19527226
]
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Erratum In:
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Acta Physiol (Oxf). 2009 Aug;196(4):447 Acta Physiol (Oxf). 2012 Mar;204(3):460 |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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