Revisiting the physiological effects of exercise training on autonomic regulation and chemoreflex control in heart failure: does ejection fraction matter?

Abstract

Heart failure (HF) is a global public health problem that, independent of its etiology [reduced (HFrEF) or preserved ejection fraction (HFpEF)], is characterized by functional impairments of cardiac function, chemoreflex hypersensitivity, baroreflex sensitivity (BRS) impairment, and abnormal autonomic regulation, all of which contribute to increased morbidity and mortality. Exercise training (ExT) has been identified as a nonpharmacological therapy capable of restoring normal autonomic function and improving survival in patients with HFrEF. Improvements in autonomic function after ExT are correlated with restoration of normal peripheral chemoreflex sensitivity and BRS in HFrEF. To date, few studies have addressed the effects of ExT on chemoreflex control, BRS, and cardiac autonomic control in HFpEF; however, there are some studies that have suggested that ExT has a beneficial effect on cardiac autonomic control. The beneficial effects of ExT on cardiac function and autonomic control in HF may have important implications for functional capacity in addition to their obvious importance to survival. Recent studies have suggested that the peripheral chemoreflex may also play an important role in attenuating exercise intolerance in HFrEF patients. The role of the central/peripheral chemoreflex, if any, in mediating exercise intolerance in HFpEF has not been investigated. The present review focuses on recent studies that address primary pathophysiological mechanisms of HF (HFrEF and HFpEF) and the potential avenues by which ExT exerts its beneficial effects.

Hypoxic Respiratory Chemoreflex Control in Young Trained Swimmers

“…Despite that the end of an apnea is related to the central command of the ventilation (Guyenet and Bayliss, 2015), most of the evidence related to regulatory responses to apnea are focused on cardiovascular responses, which has been linked to the sports performance (Costill et al, 1991;Rodríguez-Zamora et al, 2012;Guimard et al, 2014;Costa et al, 2015;Viana et al, 2019). However, considering that PaO 2 decreases and PaCO 2 increases during apneas (Muth et al, 2003) and, that respiratory regions, at the brainstem level, could modulate the cardiovascular autonomic responses (Andrade et al, 2018;Díaz et al, 2020), the longer duration of apnea and cardiovascular adjustments to the apnea observed in swimmers, may be related to neural control of breathing, through a desensitization of peripheral chemoreceptors to hypoxia and hypercapnia. However, it has not been studied yet in swimmers.…”

Neuroinflammation in heart failure: new insights for an old disease

“…; Gronda & Vanoli, ; Andrade et al . ). Given the important role of the NTS in integrating chemoreceptor and baroreceptor input, it is plausible that alterations in NTS function may also contribute to HF progression, but at this point its role is not clear and further research is needed (Toledo et al .…”

“…Chemoreflex sensitivity is a novel candidate that may contribute to the observed differences between HFrEF and HFpEF (Andrade et al . ; Del Rio et al . ; Toledo et al .…”

“…Also, both HF syndromes are accompanied by decreased vagal activity (Gronda & Vanoli, ; Andrade et al . ), which would indicate that the inflammatory reflex should be also depressed in HF. Hence, available evidence suggests that the actual contribution of this reflex to human and experimental HF pathophysiology is minimum.…”

Exercise Intolerance in Volume Overload Heart Failure Is Associated With Low Carotid Body Chemosensitivity

“…Heart failure (HF) is a global public health problem characterized by autonomic abnormalities and impaired cardiac function [1][2][3][4][5][6][7][8] . Current pharmaceutical approaches to HF treatment are effective in delaying disease progression; however, the 5-year mortality rate is approximately 50% 9 .…”