Heart rate variability as a measure of autonomic function during weight change in humans

Abstract

Changes in autonomic function were studied during experimentally induced weight changes in seven subjects. A spectral analysis of heart rate variability (HRV) was used to evaluate autonomic activity during weight change. With a 10% increase in body weight above the usual or starting weight, there was a decline in parasympathetic power accompanied by a rise in mean heart rate. Heart rate declined during weight reduction, but the power of HRV did not change significantly. Because heart rate power at the frequency of respiratory rate can be affected by respiratory rate, three additional subjects were tested at a constant respiratory rate. Weight increases in this group also led to a decline in the power of HRV at a frequency attributable to the parasympathetic nervous system. Such a parasympathetic effect of weight increase may be one mechanism for the arrhythmias and other cardiac alterations that accompany obesity.

Insulin downregulates M2-muscarinic receptors in adult rat atrial cardiomyocytes: a link between obesity and cardiovascular complications

“…32,35 Our characterization of the muscarinic signaling system in atrial cardiomyocytes could explain certain clinical features seen in obese patients with hyperinsulinemia, such as hypertension, tachycardia or increased risk of sudden cardiac death. Previous clinical studies have found that a lower parasympathetic function was associated with increasing body fat, 11,36,37 and that parasympathetic withdrawal in obese patients was correlated with hyperinsulinemia. 19 Moreover, evidence converges on the conclusion that abnormal variations in plasma insulin levels elicit repeated Insulin effect on cardiac M 2 -muscarinic receptor and signaling A Pathak et al episodes of parasympathetic withdrawal.…”

Electrocardiographic QTc interval: short-term weight loss effects

“…14 Lastly, autonomic disturbances are reported in the obese state 17,18 and with weight loss under controlled experimental conditions. 19 Thus, although mechanisms of cardiac repolarization change were not explored in the present study, autonomic mechanisms may in-part explain the observed QT and QTc interval reductions.…”

Arterial stiffness, central blood pressure and body size in health and disease

“…Perhaps more important are the observations of impaired heart rate variability, increased heart rate, cardiac output and peripheral vasodilation in overweight individuals that are apparently healthy, normotensive and normoglycemic. 18,28 This 'high-output, low-resistance' haemodynamic milieu will reasonably be expected to result in significantly lower central SBP compared with peripheral SBP (increased SBP amplification), and thereby potentially help explain the differential relationships between body size and central versus peripheral BP. 23,29 Further studies are needed to understand the relation between body size and central BP.…”