| Relationships between the extent of apnea-induced bradycardia and the vascular response in the arm and leg during dynamic two-legged knee extension exercise. | |
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MedLine Citation:
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PMID: 22159992 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Our aim was to test the hypothesis that apnea-induced hemodynamic responses during dynamic exercise in humans differ between those who show strong bradycardia and those who show only mild bradycardia. After apnea-induced changes in heart rate (HR) were evaluated during dynamic exercise, 23 healthy subjects were selected and divided into a large response group (L group; n = 11) and a small response group (S group; n = 12). While subjects performed a two-legged dynamic knee extension exercise at a work load that increased HR by 30 beats/min, apnea-induced changes in HR, cardiac output (CO), mean arterial pressure (MAP), arterial O(2) saturation (Sa(O(2))), forearm blood flow (FBF), and leg blood flow (LBF) were measured. During apnea, HR in the L group (54 ± 2 beats/min) was lower than in the S group (92 ± 3 beats/min, P < 0.05). CO, Sa(O(2)), FBF, LBF, forearm vascular conductance (FVC), leg vascular conductance (LVC), and total vascular conductance (TVC) were all reduced, and MAP was increased in both groups, although the changes in CO, TVC, LBF, LVC, and MAP were larger in the L group than in the S group (P < 0.05). Moreover, there were significant positive linear relationships between the reduction in HR and the reductions in TVC, LVC, and FVC. We conclude that individuals who show greater apnea-induced bradycardia during exercise also show greater vasoconstriction in both active and inactive muscle regions. |
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Authors:
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Takeshi Nishiyasu; Rina Tsukamoto; Katsuhito Kawai; Keiji Hayashi; Shunsaku Koga; Masashi Ichinose |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2011-12-09 |
Journal Detail:
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Title: American journal of physiology. Heart and circulatory physiology Volume: 302 ISSN: 1522-1539 ISO Abbreviation: Am. J. Physiol. Heart Circ. Physiol. Publication Date: 2012 Feb |
Date Detail:
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Created Date: 2012-02-01 Completed Date: 2012-03-20 Revised Date: 2012-05-23 |
Medline Journal Info:
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Nlm Unique ID: 100901228 Medline TA: Am J Physiol Heart Circ Physiol Country: United States |
Other Details:
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Languages: eng Pagination: H864-71 Citation Subset: IM |
Affiliation:
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Institute of Health and Sports Science, University of Tsukuba, Tsukuba, Japan. nisiyasu@taiiku.tsukuba.ac.jp |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Apnea
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complications,
physiopathology* Arm / blood supply, physiology Bicycling / physiology Bradycardia / etiology, physiopathology* Exercise / physiology* Female Heart Rate / genetics, physiology Humans Leg / blood supply, physiology Male Models, Cardiovascular Muscle, Skeletal / blood supply, physiology Physical Exertion / physiology* Regional Blood Flow / physiology Vasoconstriction / physiology Young Adult |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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