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Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow
Muscle sympathetic nerve activity (MSNA) is not increased during leg cycling at light and mild intensities, despite activation of central command and the exercise pressor reflex. We determined whether increasing central blood volume and loading the cardiopulmonary baroreceptors modulate sympathetic...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
Wiley Periodicals, Inc.
2014
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4187562/ https://www.ncbi.nlm.nih.gov/pubmed/25347854 http://dx.doi.org/10.14814/phy2.12070 |
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author | Katayama, Keisho Ishida, Koji Saito, Mitsuru Koike, Teruhiko Hirasawa, Ai Ogoh, Shigehiko |
author_facet | Katayama, Keisho Ishida, Koji Saito, Mitsuru Koike, Teruhiko Hirasawa, Ai Ogoh, Shigehiko |
author_sort | Katayama, Keisho |
collection | PubMed |
description | Muscle sympathetic nerve activity (MSNA) is not increased during leg cycling at light and mild intensities, despite activation of central command and the exercise pressor reflex. We determined whether increasing central blood volume and loading the cardiopulmonary baroreceptors modulate sympathetic vasomotor outflow during leg cycling. To this end, we changed the pedaling frequency to enhance skeletal muscle pump. Subjects performed two leg cycle exercises at differential pedal rates of 60 and 80 rpm (60EX and 80EX trials) for two conditions (with and without MSNA measurement). In each trial, subjects completed leg cycling with a differential workload to maintain constant oxygen consumption (VO(2)). MSNA was recorded via microneurography at the right median nerve of the elbow. Without MSNA measurement, thoracic impedance, stroke volume (SV), and cardiac output (CO) were measured non‐invasively using impedance cardiography. Heart rate and VO(2) during exercise did not differ between the 60EX and 80EX trials. Changes in thoracic impedance, SV, and CO during the 80EX trial were greater than during the 60EX trial. MSNA during the 60EX trial was unchanged compared with that at rest (25.8 ± 3.1 [rest] to 28.3 ± 3.4 [exercise] bursts/min), whereas a significant decrease in MSNA was observed during the 80EX trial (25.8 ± 2.8 [rest] to 19.7 ± 2.0 [exercise] bursts/min). These results suggest that a muscle pump‐induced increase in central blood volume, and thereby loading of cardiopulmonary baroreceptors, could inhibit sympathetic vasomotor outflow during mild dynamic leg exercise, despite activation of central command and the exercise pressor reflex. |
format | Online Article Text |
id | pubmed-4187562 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2014 |
publisher | Wiley Periodicals, Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-41875622014-11-12 Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow Katayama, Keisho Ishida, Koji Saito, Mitsuru Koike, Teruhiko Hirasawa, Ai Ogoh, Shigehiko Physiol Rep Original Research Muscle sympathetic nerve activity (MSNA) is not increased during leg cycling at light and mild intensities, despite activation of central command and the exercise pressor reflex. We determined whether increasing central blood volume and loading the cardiopulmonary baroreceptors modulate sympathetic vasomotor outflow during leg cycling. To this end, we changed the pedaling frequency to enhance skeletal muscle pump. Subjects performed two leg cycle exercises at differential pedal rates of 60 and 80 rpm (60EX and 80EX trials) for two conditions (with and without MSNA measurement). In each trial, subjects completed leg cycling with a differential workload to maintain constant oxygen consumption (VO(2)). MSNA was recorded via microneurography at the right median nerve of the elbow. Without MSNA measurement, thoracic impedance, stroke volume (SV), and cardiac output (CO) were measured non‐invasively using impedance cardiography. Heart rate and VO(2) during exercise did not differ between the 60EX and 80EX trials. Changes in thoracic impedance, SV, and CO during the 80EX trial were greater than during the 60EX trial. MSNA during the 60EX trial was unchanged compared with that at rest (25.8 ± 3.1 [rest] to 28.3 ± 3.4 [exercise] bursts/min), whereas a significant decrease in MSNA was observed during the 80EX trial (25.8 ± 2.8 [rest] to 19.7 ± 2.0 [exercise] bursts/min). These results suggest that a muscle pump‐induced increase in central blood volume, and thereby loading of cardiopulmonary baroreceptors, could inhibit sympathetic vasomotor outflow during mild dynamic leg exercise, despite activation of central command and the exercise pressor reflex. Wiley Periodicals, Inc. 2014-07-17 /pmc/articles/PMC4187562/ /pubmed/25347854 http://dx.doi.org/10.14814/phy2.12070 Text en © 2014 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society. http://creativecommons.org/licenses/by/3.0/ This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Original Research Katayama, Keisho Ishida, Koji Saito, Mitsuru Koike, Teruhiko Hirasawa, Ai Ogoh, Shigehiko Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow |
title | Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow |
title_full | Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow |
title_fullStr | Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow |
title_full_unstemmed | Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow |
title_short | Enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow |
title_sort | enhanced muscle pump during mild dynamic leg exercise inhibits sympathetic vasomotor outflow |
topic | Original Research |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4187562/ https://www.ncbi.nlm.nih.gov/pubmed/25347854 http://dx.doi.org/10.14814/phy2.12070 |
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