The Association between Central Adiposity and Autonomic Dysfunction in Obesity

Abstract

Objective: To determine the relationship between central adiposity parameters and autonomic nervous system (ANS) dysfunction. Subjects and Methods: The study included 114 obese individuals without any cardiovascular risk factors. Weight (in kg), height (in m), and waist circumference (WC; in cm) were measured and body mass index was calculated. Echocardiographic examination was performed to measure left ventricular mass and epicardial fat thickness (EFT). All the participants underwent an exercise test and electrophysiological evaluation using electromyography. Heart rate recovery (HRR) at 1-5 min, R-R interval variation at rest and during hyperventilation, and sympathetic skin response were measured. Pearson's correlation analysis was used. Multiple linear regression analysis was used to identify the factors associated with autonomic dysfunction. Results: The HRR at 1-5 min was negatively correlated with WC and age (WC-HRR1: r = -0.32; WC-HRR2: r = -0.31; WC-HRR3: r = -0.26; WC-HRR4: r = -0.23; WC-HRR5: r = -0.21; age-HRR2: r = -0.32; age-HRR3: r = -0.28; age-HRR4: r = -0.41; age-HRR5: r = -0.42). Age was the only independent predictor of reduced HRR at 1-5 min. In addition, WC predicted a reduced HRR at 3 min. There were no significant associations between central obesity and electrophysiological parameters. EFT was not associated with ANS dysfunction. Conclusion: In this study, central adiposity and aging were associated with ANS dysfunction in obese individuals. The WC could be a marker of ANS dysfunction in obese individuals without any cardiovascular risk factors. The HRR assessment at a later decay phase could be more valuable for evaluating ANS function than during early recovery.

Leptin as a Mediator of Obesity-Induced Hypertension

“…Data from human studies as well as animal models have suggested that obesity leads to alterations in autonomic regulation, particularly an increase in sympathetic nerve activity to various tissues [3]. Indeed, obesity-induced hypertension has been linked to increased sympathetic outflow to the kidney, which leads to increased fluid retention and vasoconstriction, as well as activation of the renin-angiotensin system; together, these promote an increase in arterial pressure [4].…”

Heart Rate Variability as a Valuable and Easy Method for the Evaluation of Cardiac Autonomic Function

“…I read the paper by Fidan-Yaylali et al [ 1 ] entitled “The Association between Central Adiposity and Autonomic Dysfunction in Obesity” with great interest. The authors reported that indices of heart rate recovery, especially those at the late decay phase, as predictors of cardiac autonomic dysfunction are impaired in obese individuals.…”

“…Cardiac autonomic dysfunction is described as a dysregulation of cardiovascular autonomic function without any other reason, inducing dysautonomia, and is accepted as an independent prognostic factor for cardiovascular morbidity and mortality [ 2 ]. Cardiovascular autonomic reflex tests (CARTs), heart rate variability (HRV), heart rate turbulence, and heart rate recovery can be used for the evaluation of cardiac autonomic dysfunction [ 1 , 3 ].…”

Hypothalamic mechanisms underlying the cardiovascular and metabolic actions of leptin

“…Strikingly, obesity is associated with cardiometabolic dysfunction even in children, with increasing body mass index correlating with higher systolic blood pressure, total cholesterol levels, and fasting blood glucose in obese [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] year olds [13]. Consistent with this, a large study of 2.3 million Israeli adolescents has recently shown that childhood obesity and even elevated body mass index within the normal range correlates with increased risk of cardiovascular-related death in adulthood [14].…”

“…While peripheral mechanisms including chronic inflammation, physical compression of the kidneys, and vascular dysfunction have been proposed as potential mediators of obesity-associated hypertension, there has been substantial evidence supporting a critical role for the central nervous system in driving this linkage. Data from human studies as well as animal models have suggested that obesity leads to alterations in autonomic regulation, particularly an increase in sympathetic nerve activity to various tissues [3]. Indeed, obesity-induced hypertension has been linked to increased sympathetic outflow to the kidney, which leads to increased fluid retention and vasoconstriction, as well as activation of the renin-angiotensin system; together, these promote an increase in arterial pressure [4].…”