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首页> 外文期刊>American Journal of Physiology >Effect of aging on renal blood flow velocity during static exercise.
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Effect of aging on renal blood flow velocity during static exercise.

机译：静态运动中衰老对肾血流速度的影响。

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During exercise, activation of the sympathetic nervous system causes reflex renal vasoconstriction. The effects of aging on this reflex are poorly understood. This study evaluated the effects of age on renal vasoconstrictor responses to handgrip. Seven older (65 +/- 9 yr) and nine younger (25 +/- 2 yr) subjects were studied. Beat-by-beat analyses of changes in renal blood flow velocity (RBV; duplex ultrasound) were performed during two handgrip paradigms. Arterial blood pressure (BP) and heart rate were also measured, and an index of renal vascular resistance (RVR) was calculated (BP/RBV). In protocol 1, fatiguing handgrip [40% of maximal voluntary contraction (MVC)] caused a greater increase in RVR in the older subjects (old 90% +/- 15 increase, young 52% +/- 4 increase; P = 0.03). During posthandgrip circulatory arrest (isolates muscle metaboreflex), the increases in RVR were only approximately 1/2 of the increase seen at end grip. In protocol 2, 15-s bouts of handgrip at graded intensities led to increases in RVR in both subject groups. This effect was not seen until 50% MVC workload (P < 0.05). RVR responses occurred early and were greater in older than in younger subjects at 50% MVC (32 +/- 6% vs. 16 +/- 5%; P = 0.02) and 70% MVC (39 +/- 11% vs. 24 +/- 8%; P = 0.02). Static exercise-induced renal vasoconstriction is enhanced with aging. Because the characteristics of this response suggest a predominant role for mechanoreceptor engagement, we hypothesize that mechanoreceptor responses are augmented with aging.
机译：在运动过程中，交感神经系统的激活引起反射性肾血管收缩。衰老对该反射的影响知之甚少。这项研究评估了年龄对肾血管收缩对手握反应的影响。研究了七名年龄较大（65 +/- 9岁）和九名年龄较小（25 +/- 2岁）的受试者。在两个手柄范例中进行了肾脏血流速度变化的逐次分析（RBV;双工超声）。还测量了动脉血压（BP）和心率，并计算了肾血管阻力指数（RVR）（BP / RBV）。在方案1中，疲劳的握力[最大自愿收缩（MVC）的40％]在较年长的受试者中引起RVR更大的增加（老者增加90％+/- 15，年轻者增加52％+/- 4; P = 0.03） 。在手握后循环停止（隔离肌肉代谢反射）期间，RVR的增加仅是末端抓地力增加的1/2左右。在方案2中，以梯度强度进行15秒钟的握力动作会导致两个受试者组的RVR升高。直到有50％的MVC工作量（P <0.05），才看到这种效果。在50％MVC（32 +/- 6％vs. 16 +/- 5％; P = 0.02）和70％MVC（39 +/- 11％vs. 24 +/- 8％; P = 0.02）。静态运动引起的肾血管收缩随着年龄的增长而增强。因为这种反应的特征表明机械感受器参与的主要作用，我们假设机械感受器反应会随着年龄的增长而增加。

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