Respiratory Sinus Arrhythmia Mechanisms in Young Obese Subjects

Abstract

Autonomic nervous system (ANS) activity and imbalance between its sympathetic and parasympathetic components are important factors contributing to the initiation and progression of many cardiovascular disorders related to obesity. The results on respiratory sinus arrhythmia (RSA) magnitude changes as a parasympathetic index were not straightforward in previous studies on young obese subjects. Considering the potentially unbalanced ANS regulation with impaired parasympathetic control in obese patients, the aim of this study was to compare the relative contribution of baroreflex and non-baroreflex (central) mechanisms to the origin of RSA in obese vs. control subjects. To this end, we applied a recently proposed information-theoretic methodology -partial information decomposition (PID) -to the time series of heart rate variability (HRV, computed from RR intervals in the ECG), systolic blood pressure (SBP) variability, and respiration (RESP) pattern measured in 29 obese and 29 ageand gender-matched non-obese adolescents and young adults monitored in the resting supine position and during postural and cognitive stress evoked by head-up tilt and mental arithmetic. PID was used to quantify the so-called unique information transferred from RESP to HRV and from SBP to HRV, reflecting, respectively, non-baroreflex and RESP-unrelated baroreflex HRV mechanisms, and the redundant information transferred from (RESP, SBP) to HRV, reflecting RESP-related baroreflex RSA mechanisms. Our results suggest that obesity is associated: (i) with blunted involvement of non-baroreflex RSA mechanisms, documented by the lower unique information transferred from RESP to HRV at rest; and (ii) with a reduced response to postural stress (but not to mental stress), documented by the lack of changes in the unique information transferred from RESP and SBP to HRV in obese subjects moving from supine to upright, and by a decreased redundant information transfer in obese compared to controls in the upright position. These findings were observed in the presence of an unchanged RSA Frontiers in Neuroscience | www.frontiersin.org 1 March 2020 | Volume 14 | Article 204 Javorka et al. RSA Mechanisms in Obesity magnitude measured as the high frequency (HF) power of HRV, thus suggesting that the changes in ANS imbalance related to obesity in adolescents and young adults are subtle and can be revealed by dissecting RSA mechanisms into its components during various challenges.

Multivariate Correlation Measures Reveal Structure and Strength of Brain–Body Physiological Networks at Rest and During Mental Stress

“…In particular, it has been shown that both mental load and physiological stress produce repeatable variations not only in the brain activity ( Gevins et al, 1998 ; Berka et al, 2007 ; Al-shargie et al, 2018 ), but also in the dynamic control of the cardiovascular function and heart rate variability (HRV) ( Petrowski et al, 2017 ; Kim et al, 2018 ; Pernice et al, 2018 , 2019a ); these effects can be of clinical relevance as they can ultimately increase the risk of heart attacks and stroke ( Steptoe and Kivimäki, 2013 ; Al-Shargie et al, 2016 ). Moreover, besides the interplay between brain and heart, the network of interactions sub-serving the regulation of the homeostatic function encompasses other physiological rhythms, such as the respiratory drive ( Pfurtscheller et al, 2019 ; Javorka et al, 2020 ), the cardiovascular and baroreflex functions ( Krohova et al, 2019 , 2020 ; Ringwood and Bagnall-Hare, 2020 ), and other less studied but significant vital signs, e.g., including muscular and ocular activities ( Ivanov et al, 2017 ; Boonstra et al, 2019 ).…”

Low-invasive multisensor real-time acquisition system for the assessment of cardiorespiratory and skin conductance parameters

“…During the CB phase, a slight increase of the heart rate can also be observed, which may be related to the fact that the subject was not used to breath in a non-spontaneous way and thus appeared a bit troubled at the beginning. Moreover, the change of the heart rate due to respiration could be related to the widely known phenomenon of Respiratory Sinus Arrhythmia (RSA) [33], [34]. The transition between controlled breathing and the second rest phase did not show any abrupt variations of GSR, which continues to gradually decrease towards the values observed during the first spontaneous breathing condition.…”

Wearable Multisensor Ring-Shaped Probe for Assessing Stress and Blood Oxygenation: Design and Preliminary Measurements

“…On the other hand, opposite trends are reported when moving from R2 to BH: the increased PPI mean, i.e., a slightly reduced heart rate, is related to respiratory sinus arrhythmia [ 58 , 59 ]. The GSR and SCL mean values again tend to rise, even if not as much as during SF, thus suggesting that breath holding protocol may elicit increased sweating.…”