In this review, we highlight the underlying mechanisms responsible for the sex differences in the exercise pressor reflex, and, importantly, the impact of sex hormones and menopausal status. The exercise pressor reflex is attenuated in pre-menopausal women compared to age-matched men. Specifically, activation of the metaboreflex (a component of the exercise pressor reflex) results in attenuated increases in blood pressure and sympathetic vasomotor outflow compared to agematched men. In addition, pre-menopausal women exhibit less transduction of sympathetic outflow to the peripheral vasculature than men. In stark contrast, post-menopausal women exhibit an augmented exercise pressor reflex arising from exaggerated metaboreflex-induced autonomic and cardiovascular reflexes. We propose that metaboreflex-induced autonomic and cardiovascular changes associated with menopause majorly contribute to the elevated blood pressure response during dynamic exercise in post-menopausal women. In addition, we discuss the potential mechanisms by which sex hormones in pre-menopausal women may impact the exercise pressor reflex as well as metaboreflex.

Aims Patients with hypertrophic obstructive cardiomyopathy (HOCM) have impaired exercise capacity. The gold standard therapy for patients with HOCM is septal myectomy surgery; however, changes in maximum oxygen uptake (VO2peak) following myectomy are variable, with VO2peak decreasing in some patients. Therefore, we evaluated changes in VO2peak following surgical myectomy to determine clinical predictors of those exhibiting decreased VO2peak post-myectomy. Methods HOCM patients ( N = 295) who performed symptom limited cardiopulmonary exercise testing prior to and following surgical myectomy were included for analysis. The VO2peak non-responder group ( n = 128) was defined as <0% change in VO2peak from pre- to post-myectomy. Step-wise regression models using demographics, clinical, and physiologic characteristics were created to determine predictors of hypertrophic cardiomyopathy patients in the VO2peak non-responder group. Results Independent predictors of the VO2peak non-responder group included higher pre-myectomy VO2peak (% predicted), older age, women, history of dyslipidemia, lack of cardiac rehabilitation enrollment, and lower body mass index (all p < 0.03). Forty-three (14.6%) patients reached the primary end-point of all-cause mortality during a median follow up of 11.25 years (interquartile range 6.94 to 16.40). After adjustment for age, sex, beta-blocker use, coronary artery disease history, and body mass index, the VO2peak non-responder group had greater risk of death compared with the VO2peak responder group (adjusted hazard ratio: 1.77, 95% confidence interval: 1.06–3.34, p = 0.01). Conclusion This large hypertrophic cardiomyopathy cohort demonstrated that demographic (i.e. female sex), lack of cardiac rehabilitation enrollment, and cardiovascular risk factors (i.e. history of dyslipidemia) are predictive of those patients that did not exhibit increases in VO2peak following septal myectomy surgery.

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Reflexes arising from the respiratory and locomotor muscles influence cardiovascular regulation during exercise. However, it is unclear how the respiratory and locomotor muscle reflexes interact when simultaneously stimulated. Herein, we demonstrate that stimulation of the respiratory and locomotor muscle reflexes yielded additive cardiovascular responses during submaximal exercise.