Muscle sympathetic nerve activity during isometric exercise in patients with cerebrovascular accidents.

虽然等长运动对改善脑血管意外（CVA）患者健侧肢体的肌力是有用的，但CVA患者在静态运动期间心血管变化引起的升压反应尚不清楚。我们比较了8名有3个月CVA病史的患者和8名对照男性对肘屈肌静态运动的心血管反应，这些患者记录了皮质下结构的损害。心率（HR），动脉血压（BP）和肌肉交感神经活动（MSNA）的变化，记录从腓总神经在患侧，前，中，后肘屈肌肌在35%的最大随意收缩持续收缩2分钟。对照组MSNA爆发次数（64.5±5.0）次/100 HR高于对照组（43.5±7.1）次/100 HR（P<0.05）。在静态运动期间，CVA和对照组的总MSNA（每分钟平均爆发振幅乘以爆发率）分别显著增加18.7±6.3%和95.8± 25.2%。与对照组相比，CVA患者的总MSNA、HR和MBP的百分比变化在静态运动期间减弱。我们的研究结果表明，CVA患者在静态运动过程中存在完整的升压反应，尽管这种反应的幅度相对于对照组有所减弱。因此，皮质下结构的损伤可能参与降低运动时的升压反应。我们的研究结果表明，静态运动不会使CVA患者的HR和BP显著增加。

Although isometric exercise is useful for improvement of muscle strength in unaffected limbs of patients with cerebrovascular accidents (CVA), the pressor responses induced by cardiovascular changes during static exercise in CVA patients are not well defined. We compared the cardiovascular responses to static exercise of elbow flexor muscle between 8 patients with 3-month history of CVA who had documented damage of subcortical structures and 8 control men. Changes in heart rate (HR), arterial blood pressure (BP) and muscle sympathetic nerve activity (MSNA), recorded from the peroneal nerve on the affected side, were determined before, during and after a 2-min sustained contraction of elbow flexor muscles at 35% maximal voluntary contraction. During the control period, the mean burst count of MSNA in CVA patients (64.5±5.0 beats/100HR) was higher than in control subjects (43.5±7.1 beats/100HR) (P<K 0.05). Total MSNA (the mean burst amplitude per minute times burst rate) increased significantly in CVA and control during static exercise by 18.7±6.3% and 95.8±25.2%, respectively. The percent changes in total MSNA, HR and MBP in CVA patients were attenuated during static exercise, compared with the control subjects. Our results indicated the presence of intact pressor responses during static exercise in CVA patients although the magnitudes of such responses were attenuated relative to the control. Therefore, damage of subcortical structures might be involved in lowering the pressor response during exercise. Our results indicate that static exercise does not put patients with CVA at risk of marked increases in HR and BP.