Oral contraceptives augment the exercise pressor reflex during isometric handgrip exercise.

Clare Minahan,Hailey O'Neill,Surendran Sabapathy,Brianna Larsen,Nelie Sikkema,Sarah Joyce

doi:10.14814/phy2.13629

Abstract

We sought to determine whether oral contraception alters the gender‐related differences observed in the exercise pressor reflex during isometric handgrip exercise. Fifteen men, fifteen normally menstruating women (WomenNM), and fifteen women taking monophasic oral contraceptives (WomenOC) completed two trials of a 3‐min isometric handgrip exercise protocol performed at 30% of their maximal voluntary contraction: (1) where arterial occlusion was applied to the previously exercising arm during a 3‐min recovery period (Occlusion trial); (2) where no arterial occlusion was applied during recovery (Control trial). Handgrip exercise elicited greater increases in mean arterial pressure (MAP) in MEN compared to both female groups (P < 0.05), and in WomenOC compared to WomenNM in both trials (P = 0.01, P = 0.03). After 3 min of recovery, sBP was 12% (P = 0.01) and 9% (P = 0.02) higher in the Occlusion trial when compared to the Control trial for MEN and WomenOC. Conversely, arterial occlusion in recovery from handgrip did not sustain elevated sBP in the Occlusion trial, and sBP returned to recovery levels not different to the Control trial, in WomenNM (P = 0.41). These data indicate that gender‐related differences in the metaboreflex during isometric handgrip exercise exist between men and normally menstruating women, but are blunted when men are compared to women taking oral contraceptives. We conclude that the suppression of 17β‐estradiol and/or progestogen in women via the administration of oral contraceptives attenuates sex‐related differences in the metaboreflex during isometric handgrip exercise.

Highlights

IntroductionThe cardiovascular responses to exercise are regulated by a combination of efferent (central drive) and afferent (neural inputs from contracting skeletal muscle, arterial chemoreflexes, and baroreflexes) signals (Kaufman and Forster 1996; Nobrega et al 2014)
The cardiovascular responses to exercise are regulated by a combination of efferent and afferent signals (Kaufman and Forster 1996; Nobrega et al 2014)
Like men, blood pressure (BP) measured in women taking oral contraception remains elevated above baseline when arterial occlusion is applied in recovery a 2018 The Authors

Summary

Introduction

The cardiovascular responses to exercise are regulated by a combination of efferent (central drive) and afferent (neural inputs from contracting skeletal muscle, arterial chemoreflexes, and baroreflexes) signals (Kaufman and Forster 1996; Nobrega et al 2014). The reflex mechanisms originating in contracting skeletal muscles that adjust blood pressure (whilst modulating heart rate and ventricular contractility) to meet the perfusive and metabolic requirements of exercise are collectively termed the exercise pressor reflex (EPR) (Nobrega et al 2014). Men and women appear to rely on different physiological mechanisms to maintain cardiovascular control (Kneale et al 2000; Reckelhoff 2001; Hart et al 2009, 2011), and evidence suggests that the EPR is attenuated in women when compared to men (Ettinger et al 1996; Jarvis et al 2011). In a highly controlled study of men and naturally cycling women, Jarvis et al (2011) demonstrated that women exhibited lower blood pressure (BP) and muscle sympathetic nerve activity (MSNA) responses compared to men during an isometric handgrip task performed at 40% of maximal voluntary contraction (MVC).

Methods

Results

Conclusion