Sex-related difference in sympathetic chemoreflex response: does it matter in clinical disease?

Abstract

We read with great interest the work of Sayegh et al. (2022) recently published in The Journal of Physiology. In their elegant study, the authors aimed to assess, for the first time, the sex-related difference in the respiratory and sympathetic neurocirculatory responses (estimated through muscle sympathetic nerve activity, MSNA) to central, peripheral and combined chemoreflex activation in 10 male and 10 female healthy volunteers. The authors confirm that ventilatory and adrenergic responses to chemoreflex activation may be partially independent within the same individual. Although both responses are initiated at similar recruitment thresholds, the sympathetic response to chemoreflex stimulation cannot be predicted from the ventilatory response, as suggested by Keir and co-workers (2019). Further, the study shows a greater total MSNA response to hypercapnia (on either hyperoxic or hypoxic background) in women, as compared to men, despite an attenuated ventilatory response to hypercapnia (Sayegh et al., 2022). The greater sympathetic response to central chemoreflex activation in women unveils potential