Although pathophysiologic links between postmenopause and healthy aging remain unclear, both factors are associated with increased blood pressure and sympathetic nerve activity (SNA) in women. Activation of polymodal musculoskeletal neural afferents originating within adventia of venules modulates SNA and blood pressure control during exercise in healthy adults. We hypothesized transient subsystolic regional circulatory occlusion (RCO) during exercise sensitizes these afferents leading to augmented systemic vascular resistance (SVR) mediated increased mean arterial pressure (MAP) in postmenopause versus premenopause. Normotensive women in premenopause or postmenopause (N=14 and N=14; ages: 30±9 and 55±71 years, respectively; P<0.01) performed: 1) peak exercise testing; 2) fixed-load cycling at 30% workloadpeak (48±11 and 38±6W, respectively; P<0.01), whereby the initial 3-minutes were control exercise without RCO (CTL), thereafter including 2-minutes of bilateral-thigh RCO to 20, 40, 60, 80, or 100 mmHg (randomized), with 2-minutes deflation between RCO. Both MAP (17±4% versus 4±4%, P=0.02) and SVR (16±8% versus -3±8%, P=0.04) increased at 80 mmHg from CTL in postmenopause versus premenopause, respectively. However, cardiac index was similar in postmenopause versus premenopause at 80 mmHg from CTL (1±6% versus 7±6%, respectively; P=0.15). There was no continuous effect of aging in MAP (P=0.12), SVR (P=0.07), or cardiac index (P=0.18) models. These data suggest transient locomotor subsystolic RCO sensitizes musculoskeletal afferents, which provoke increased SVR to generate augmented MAP during exercise in postmenopause. These observations provide a novel approach for understanding the age independent variability in exercise blood pressure control across the normotensive adult pre-to-postmenopause spectrum.
- regional circulatory occlusion
- cardiac output
- exercise pressor reflex
- aging women
- group III-Aδ and IV-C neural afferents
- Copyright © 2016, American Journal of Physiology-Heart and Circulatory Physiology