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

虽然等长运动有助于改善脑血管意外（CVA）患者未受影响肢体的肌肉力量，但CVA患者静态运动中心血管变化引起的升压反应尚不明确。我们比较了8名有3个月CVA病史且有皮层下结构损伤的患者和8名对照男性患者对肘关节屈肌静态运动的心血管反应。测定患侧腓神经记录的心率（HR）、动脉血压（BP）和肌肉交感神经活动（MSNA）的变化，在肘关节屈肌以35%最大自愿收缩持续收缩2分钟之前、期间和之后。对照期间，CVA患者的MSNA平均爆发次数（64.5±5.0次/100HR）高于对照组（43.5±7.1次/100HR） （P< 0.05）。静态运动时，CVA组和对照组的总MSNA（每分钟平均爆发幅度乘以爆发率）分别显著增加18.7±6.3%和95.8±25.2%。与对照组相比，静态运动时CVA患者总MSNA、HR和MBP的百分比变化有所减弱。我们的研究结果表明，CVA患者在静态运动中存在完整的血压反应，尽管这种反应的强度相对于对照组有所减弱。因此，皮质下结构的损伤可能与运动中降压反应的降低有关。我们的研究结果表明，静态运动不会使CVA患者的HR和血压显著升高。

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.