Muscle metaboreflex control is diminished in normotensive obese women

1  Heart Institute (InCor), 2  Department of Endocrinology, University of São Paulo Medical School, and 3  School of Physical Education and Sports, University of São Paulo, São Paulo, Cep 05403-000 Brazil There is no information about the muscle metaboreflex control in obese individuals. In 40 normo...

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Published in:American journal of physiology. Heart and circulatory physiology 2001-08, Vol.281 (2), p.H469-H475
Main Authors: Negrao, Carlos Eduardo, Trombetta, Ivani C, Batalha, Luciana T, Ribeiro, Mauricio Maltez, Rondon, Maria Urbana P. Brandao, Tinucci, Tais, Forjaz, Claudia L. M, Barretto, Antonio Carlos P, Halpern, Alfredo, Villares, Sandra M. F
Format: Article
Language:English
Subjects:
Adult
Exercise
Female
Humans
Muscle Contraction
Muscle, Skeletal - innervation
Muscle, Skeletal - physiopathology
Obesity - physiopathology
Reflex
Sympathetic Nervous System - physiopathology
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Summary:1  Heart Institute (InCor), 2  Department of Endocrinology, University of São Paulo Medical School, and 3  School of Physical Education and Sports, University of São Paulo, São Paulo, Cep 05403-000 Brazil There is no information about the muscle metaboreflex control in obese individuals. In 40 normotensive obese women (OW; body mass index 33.5 ± 0.4 kg/m 2 , age 32.4 ± 1.1 yr) and 15 age-matched, normotensive lean women (LW; body mass index 22.7 ± 0.8 kg/m 2 , age 34.4 ± 1.4 yr), we measured muscle sympathetic nerve activity (MSNA) and forearm blood flow (FBF) in the nonexercising forearm during static exercise at 10 and 30% of maximal voluntary contraction (MVC). Baseline MSNA (38 ± 2 vs. 31 ± 1 bursts/min, P  = 0.001) and mean blood pressure were significantly higher in OW compared with LW. FBF was significantly lower, whereas forearm vascular resistance was significantly higher in OW. During 10% MVC, MSNA increased similarly in both groups, but during 30% MVC, MSNA was higher in LW. FBF and forearm vascular resistance responses during both 10 and 30% MVC were similar between groups. During posthandgrip circulatory arrest, MSNA remained significantly elevated compared with baseline in both groups, but this increase was significantly lower in OW (3.8 ± 0.82 vs. 9.4 ± 1.03 bursts/min, P  = 0.002). In conclusion, muscle metaboreflex control of MSNA is blunted in OW. MSNA responses are not augmented during selective activation of central command/mechanoreceptors and metaboreceptors, despite increased MSNA levels in OW. Muscle vasodilatory response during graded handgrip isometric exercise is preserved in OW. obesity; sympathetic nerve activity
ISSN:0363-6135
1522-1539
DOI:10.1152/ajpheart.2001.281.2.h469