AUTHOR=Silva Lucas R. B. E. , Zamunér Antonio R. , Gentil Paulo , Alves Fagner M. , Leal Acácia G. F. , Soares Viviane , Silva Maria S. , Vieira Marcus F. , Simões Karina , Pedrino Gustavo R. , Rebelo Ana C. S. 

TITLE=Cardiac Autonomic Modulation and the Kinetics of Heart Rate Responses in the On- and Off-Transient during Exercise in Women with Metabolic Syndrome

JOURNAL=Frontiers in Physiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/physiology/articles/10.3389/fphys.2017.00542

DOI=10.3389/fphys.2017.00542

ISSN=1664-042X

ABSTRACT=<p><bold>Objective:</bold> To test whether women with metabolic syndrome (MS) have impairments in the on- and off-transients during an incremental test and to study whether any of the MS components are independently associated with the observed responses.</p><p><bold>Research Design and Methods:</bold> Thirty-six women aged 35–55 years were divided into a group with MS (MSG, <italic>n</italic> = 19) and a control group (CG, <italic>n</italic> = 17). R-R intervals (RRi) and heart rate variability (HRV) were calculated on a beat-to-beat basis and the heart rate (HR) at the on- and off-transient were analyzed during an incremental cardiopulmonary exercise test (CPET).</p><p><bold>Results:</bold> MSG showed lower aerobic capacity and lower parasympathetic cardiac modulation at rest compared with CG. HR values in on-transient phase were significantly lower in MSG compared with CG. The exponential amplitudes “amp” and the parameters “τ” [speed of heart rate recovery (HRR)] were lower in MSG. MSG exhibited higher HR values in comparison to CG during the off-transient indicating a slower HRR. In MSG, there was an inverse and significant correlation between fasting plasma vs. ΔF and glucose vs. exponential “τ” of HRR dynamics.</p><p><bold>Conclusion:</bold> MS is associated with poor heart rate kinetics. The altered HR kinetics seems to be related to alterations in cardiac parasympathetic modulation, and glucose metabolism seems to be the major determinant.</p>