Oral contraceptives modulate the muscle metaboreflex in healthy young women

Abstract

There are known sex differences in blood pressure regulation. The differences are related to ovarian hormones that influence β-adrenergic receptors and the transduction of muscle sympathetic nerve activity. Oral contraceptives (OC) modulate the ovarian hormonal profile in women and therefore may alter the cardiovascular response. We questioned if OC would alter the absolute pressor response to static exercise and influence the day-to-day variability of the response. Healthy men (n = 11) and women (n = 19) completed a familiarization day and 2 experimental testing days. Women were divided into those taking (W-OC, n = 10) and not taking (W-NC, n = 9) OC. Each experimental testing day involved isometric handgripping exercise, at 30% of maximal force, followed by circulatory occlusion to isolate the metaboreflex. Experimental days in men were 7-14 days apart. The first experimental testing in W-OC occurred 2-7 days after the start of the active phase of their OC. Women not taking OC were tested during the early and late follicular phase of the menstrual cycle as determined by commercial ovulation monitor. The increase in mean arterial pressure (MAP) during exercise was significantly lower in W-NC (95 ± 4 mm Hg) compared with men (114 ± 4 mm Hg) and W-OC (111 ± 3 mm Hg) (P < 0.05), with the differences preserved during circulatory occlusion. The rise in MAP was significantly correlated between the 2 testing days in men (r = 0.72, P < 0.01) and W-OC (r = 0.77, P < 0.05), but not in W-NC (r = 0.17, P = 0.67), indicating greater day-to-day variation in W-NC. In conclusion, OC modulate the exercise pressor response in women and minimize day-to-day variability in the exercise metaboreflex.

TRPV1 and BDKRB2 receptor polymorphisms can influence the exercise pressor reflex

“…Interestingly, we observed that ASIC3 rs2288645 and PTGER2 rs17197 both impacted systolic BP during PECO, but not static handgrip, in men. This is consistent with the need for a larger ischaemic stimulus to activate these pathways, and with evidence that men have greater BP response to static handgrip and PECO (Notay et al 2018;Parmar et al 2018). It is also important to consider methodological limitations of using PECO to isolate the haemodynamic contributions of the muscle metaboreflex.…”

“…; Parmar et al . ). It is also important to consider methodological limitations of using PECO to isolate the haemodynamic contributions of the muscle metaboreflex.…”

Effects of sex and ageing on the human respiratory muscle metaboreflex

“…The potential inhibitory effect is lost following menopause when circulating oestrogen levels decrease significantly (Barnes et al., 2014; Hart et al., 2011). The effects of oestrogen on the metaboreflex have been observed in humans performing isometric forearm exercise (Ettinger et al., 1998; Parmar et al., 2018) but its role with respect to the respiratory musculature is unknown.…”

Gender Differences in Hemodynamic Regulation and Cardiovascular Adaptations to Dynamic Exercise

“…This effect appears independent of muscle mass, workload, and level of training [75]. Moreover, the administration of oral contraceptives was found to attenuate sex-related differences in the metaboreflex [77,78]. Similarly, the mechanic arm of the exercise pressor reflex (i.e.…”

“…The influence of gender on exercise pressor reflex was addressed in a number of studies [75][76][77][78][79]. From these investigations it can be gleaned that the metabolic part of the exercise pressor reflex (i.e.…”