| Analysis of initial autonomic adjustments to moderate exercise in humans. | |
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MedLine Citation:
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PMID: 8903628 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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OBJECTIVE: To determine whether signs of cardiac sympathetic activation (together with vagal withdrawal) can be observed in the autonomic balance modulating the sino-atrial node as early as the initial levels of a graded light dynamic exercise. PATIENTS AND METHODS: We studied 15 healthy ambulant subjects (mean +/- SD age 32 +/- 9 years; systolic/diastolic blood pressure 120 +/- 19/77 +/- 7 mmHg; heart rate 65 +/- 9 beats/min), who underwent a control recording of 10 min, followed by a three-step progressive (10, 20 and 30% of nominal maximum for age and sex) supine bicycle exercise. Spectral and cross-spectral analysis of RR and systolic arterial pressure variabilities were used to obtain non-invasive markers of the autonomic adjustments to exercise. RESULTS: The low-frequency component of RR interval variability (which, in normalized units, is a marker of sympathetic modulation of the sino-atrial (SA) node) was progressively increased during all three stages of bicycle exercise. No significant changes were observed in the low-frequency component of systolic arterial pressure variability (i.e. a marker of sympathetic drive to the vasculature) in the early stages of exercise, while a significant increase was observed at 30% of maximum. The index alpha (which provides a measure of the gain of the arterial pressure-heart period baroreflex) was progressively reduced during all three stages of exercise. CONCLUSIONS: While the sympathovagal balance modulating the SA node is immediately shifted towards sympathetic predominance (and vagal withdrawal), markers of peripheral vascular sympathetic activation appear increased only when 30% of maximum exercise is attained. |
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Authors:
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D Lucini; V Trabucchi; A Malliani; M Pagani |
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Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Journal of hypertension Volume: 13 ISSN: 0263-6352 ISO Abbreviation: J. Hypertens. Publication Date: 1995 Dec |
Date Detail:
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Created Date: 1997-03-19 Completed Date: 1997-03-19 Revised Date: 2004-11-17 |
Medline Journal Info:
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Nlm Unique ID: 8306882 Medline TA: J Hypertens Country: ENGLAND |
Other Details:
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Languages: eng Pagination: 1660-3 Citation Subset: IM |
Affiliation:
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Centre for Cardiovascular Research (CNR), University of Milan, Italy. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Blood Pressure Electrocardiography Exercise / physiology* Female Humans Male Sinoatrial Node / innervation*, physiology Vagus Nerve / physiology* |
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