Van Iterson Erik H, Gramm Courtney, Randall Nicholas R, Olson Thomas P
Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota
Department of Cardiovascular Diseases, Mayo Clinic, Rochester, Minnesota.
Am J Physiol Heart Circ Physiol. 2016 Dec 1;311(6):H1382-H1391. doi: 10.1152/ajpheart.00310.2016. Epub 2016 Oct 7.
Although pathophysiological 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 vs. premenopause. Normotensive women in premenopause or postmenopause (n = 14 and 14; ages: 30 ± 9 and 55 ± 7 yr, respectively; P < 0.01) performed: 1) peak exercise testing and 2) fixed-load cycling at 30% peak workload (48 ± 11 and 38 ± 6 W, respectively; P < 0.01), whereby the initial 3 min were control exercise without RCO (CTL), thereafter including 2 min of bilateral-thigh RCO to 20, 40, 60, 80, or 100 mmHg (randomized), with 2 min deflation between RCO. Both MAP (17 ± 4 vs. 4 ± 4%, P = 0.02) and SVR (16 ± 8 vs. -3 ± 8%, P = 0.04) increased at 80 mmHg from CTL in postmenopause vs. premenopause, respectively. However, cardiac index was similar in postmenopause vs. premenopause at 80 mmHg from CTL (1 ± 6 vs. 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.
尽管绝经后与健康衰老之间的病理生理联系尚不清楚，但这两个因素都与女性血压升高和交感神经活动（SNA）增加有关。在健康成年人运动期间，源自微静脉外膜的多模式肌肉骨骼神经传入纤维的激活可调节SNA和血压控制。我们假设运动期间短暂的收缩期区域循环闭塞（RCO）会使这些传入纤维敏感化，从而导致绝经后与绝经前相比，全身血管阻力（SVR）介导的平均动脉压（MAP）升高。绝经前或绝经后的血压正常女性（n = 14和14；年龄分别为30±9岁和55±7岁；P < 0.01）进行：1）运动峰值测试和2）在30%峰值工作量（分别为48±11和38±6 W；P < 0.01）下进行固定负荷骑行，其中最初3分钟为无RCO的对照运动（CTL），此后包括2分钟双侧大腿RCO至20、40、60、80或100 mmHg（随机），RCO之间有2分钟放气。与绝经前相比，绝经后在80 mmHg时MAP（17±4 vs. 4±4%，P = 0.02）和SVR（16±8 vs. -3±8%，P = 0.04）分别从CTL时升高。然而，与绝经前相比，绝经后在80 mmHg时心脏指数与CTL时相似（分别为1±6 vs. 7±6%；P = 0.15）。在MAP（P = 0.12）、SVR（P = 0.07）或心脏指数（P = 0.18）模型中，衰老没有持续影响。这些数据表明，短暂的运动收缩期RCO会使肌肉骨骼传入纤维敏感化，从而在绝经后运动期间引发SVR升高以产生升高的MAP。这些观察结果为理解血压正常的成年绝经前至绝经后范围内运动血压控制中与年龄无关的变异性提供了一种新方法。
