Department of Physical Therapy and Rehabilitation Science, Carver College of Medicine, University of Iowa , Iowa City, Iowa.
Abboud Cardiovascular Research Center, Carver College of Medicine, University of Iowa , Iowa City, Iowa.
J Appl Physiol (1985). 2018 Mar 1;124(3):583-591. doi: 10.1152/japplphysiol.00411.2017. Epub 2017 Sep 28.
Habitual aerobic exercise attenuates elevated vasoconstriction during acute exercise (functional sympatholysis) in older men; however, this effect remains unknown in postmenopausal women (PMW). This study tested the hypothesis that PMW who participate in habitual aerobic exercise demonstrate a greater functional sympatholysis compared with their untrained counterparts. Nineteen PMW (untrained n = 9 vs. trained n = 10) performed 5 min of steady-state (SS) forearm exercise at relative [10% and 20% of maximum voluntary contraction (MVC)] and absolute (5 kg) contraction intensities. Lower-body negative pressure (LBNP) was used to increase sympathetic vasoconstriction during rest and forearm exercise. Brachial artery diameter and blood velocities (via Doppler ultrasound) determined forearm blood flow (FBF; ml/min). Forearm muscle oxygen consumption ([Formula: see text]; ml/min) and arteriovenous oxygen difference (a-vO) were estimated during SS-exercise and SS-exercise with LBNP. Forearm vascular conductance (FVC; ml·min·100 mmHg) was calculated from FBF and mean arterial pressure (MAP; mmHg). Vasoconstrictor responsiveness was determined as the %change in FVC during LBNP. The reduction in FVC (% change FVC) during LBNP was lower in trained compared with untrained PMW at 10% MVC (-7.3 ± 1.2% vs. -13.0 ± 1.1%; P < 0.05), 20% MVC (-4.4 ± 0.8% vs. -8.6 ± 1.4%; P < 0.05), and 5 kg (-5.3 ± 0.8% vs. -8.9 ± 1.4%; P < 0.05) conditions, whereas there were no differences at rest (-32.7 ± 4.4% vs. -33.7 ± 4.0%). Peripheral (FVC, FBF, and [Formula: see text]) and the magnitude change in systemic hemodynamics (heart rate and MAP) did not differ between groups during exercise. Collectively, the findings present the first evidence suggesting that PMW who participate in aerobic exercise demonstrate a greater functional sympatholysis compared with untrained PMW during mild to moderate forearm exercise. NEW & NOTEWORTHY Habitual aerobic exercise attenuates the elevated sympathetic nervous system-induced vasoconstriction during an acute bout of exercise (improved functional sympatholysis) in aging men; however, this effect remains unknown in postmenopausal women (PMW). The novel findings of this study suggest that habitual aerobic exercise results in an enhanced functional sympatholysis in PMW. Conversely, habitual aerobic exercise does not alter blood flow and oxygen utilization during acute forearm exercise compared with PMW who do not habitually exercise.
习惯性有氧运动可减轻老年男性急性运动期间升高的血管收缩（功能性交感神经松弛）；然而，绝经后妇女（PMW）的这种效果尚不清楚。本研究旨在验证以下假设：即与未经训练的 PMW 相比，进行习惯性有氧运动的 PMW 表现出更大的功能性交感神经松弛。19 名 PMW（未经训练的 n=9 名与训练的 n=10 名）在相对（10%和 20%最大自主收缩（MVC））和绝对（5 公斤）收缩强度下进行 5 分钟的稳态（SS）前臂运动。下肢负压（LBNP）用于在休息和前臂运动期间增加交感神经血管收缩。通过多普勒超声测量肱动脉直径和血流速度（血流）来确定前臂血流量（FBF；ml/min）。在 SS 运动和 SS 运动加 LBNP 期间，估计前臂肌肉耗氧量（[公式：见正文]；ml/min）和动静脉氧差（a-vO）。根据 FBF 和平均动脉压（mmHg）计算前臂血管传导率（FVC；ml·min·100 mmHg）。通过 LBNP 期间 FVC 的变化百分比确定血管收缩反应性。与未经训练的 PMW 相比，训练有素的 PMW 在 10% MVC（-7.3±1.2%与-13.0±1.1%；P<0.05）、20% MVC（-4.4±0.8%与-8.6±1.4%；P<0.05）和 5 公斤（-5.3±0.8%与-8.9±1.4%；P<0.05）条件下的 FVC 降低百分比（LBNP）较低，而在休息时（-32.7±4.4%与-33.7±4.0%）则没有差异。在运动期间，两组之间的外周（FVC、FBF 和 [公式：见正文]）和全身血液动力学变化幅度（心率和 MAP）没有差异。总之，这些发现首次表明，与未经训练的 PMW 相比，进行有氧运动的 PMW 在轻度至中度前臂运动期间表现出更大的功能性交感神经松弛。新的和值得注意的是，习惯性有氧运动可减轻衰老男性急性运动期间升高的交感神经诱导的血管收缩（改善功能性交感神经松弛）；然而，绝经后妇女（PMW）的这种效果尚不清楚。本研究的新发现表明，习惯性有氧运动可增强 PMW 的功能性交感神经松弛。相反，与不习惯性运动的 PMW 相比，习惯性有氧运动不会改变急性前臂运动期间的血流量和氧气利用。
