The effects of weight loss versus weight loss maintenance on sympathetic nervous system activity and metabolic syndrome components

Nora E. Straznicky, Mariee T. Grima, Nina Eikelis, Paul J. Nestel, Tye Dawood, Markus P. Schlaich, Reena Chopra, Kazuko Masuo, Murray D. Esler, Carolina I. Sari, Gavin W. Lambert, Elisabeth A. Lambert

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71 Citations (Scopus)

Abstract

Context: Sympathetic nervous system (SNS) overactivity participates in both the pathogenesis and adverse clinical complications of metabolic syndrome (MetS) obesity. Objective: We conducted a prospective lifestyle intervention trial to compare the effects of active weight loss and extended weight loss maintenance on SNS function and MetS components. Methods: Untreated subjects (14 males, four females; mean age, 53±1 yr; body mass index, 30.9±0.9 kg/m2) who fulfilled Adult Treatment Panel III criteria were randomized to 12-wk hypocaloric diet alone (n = 8) or together with aerobic exercise training (n = 10). This was followed by a 4-month weight maintenance period. Measurements of muscle sympathetic nerve activity (MSNA) by microneurography, whole-body norepinephrine kinetics, substrate oxidation by indirect calorimetry, baroreflex sensitivity, plasma renin activity (PRA), and MetS components were performed. Results: Body weight decreased by 9.3±0.8% at wk12 (P<0.001), and this was maintained. During active weight loss, norepinephrine spillover rate decreased by 23±16% (P=0.004), MSNA by 25±3 bursts per 100 heartbeats (P < 0.001), and PRA by 0.25 ± 0.09 ng/ml • h (P = 0.007), whereas baroreflex sensitivity increased by 5.2 ± 2.2 msec/mm Hg (P = 0.005). After weight maintenance, beneficial effects of weight loss on norepinephrine spillover rate were preserved, whereas PRA and MSNA rebounded (by 0.24±0.11 ng/ml • h, P=0.02; and 20±5 bursts/100 heartbeats, P=0.0003), and baroreflex sensitivity was attenuated. Conclusions: Divergent effects of successful weight loss maintenance on whole-body norepinephrine spillover rate and MSNA suggest organ-specific differentiation in SNS adaptation to weight loss under conditions of negative vs. stable energy balance.

Original languageEnglish
JournalJournal of Clinical Endocrinology and Metabolism
Volume96
Issue number3
DOIs
Publication statusPublished - Mar 2011
Externally publishedYes

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