Cardiopulmonary and Metabolism Research Laboratory, Department of Kinesiology, The University of Toledo, Toledo, OH 43606-3390, USA.
Appl Physiol Nutr Metab. 2011 Feb;36(1):137-44. doi: 10.1139/H10-097.
Skeletal muscle contractions are associated with physical stimuli that act upon muscle vasculature, including increased shear stress and blood pressure. It is unclear if acute dynamic exercise alters local vascular function. The purpose of this study was to examine the role of exercise hemodynamics on the effects of acute exercise on vascular function, as evaluated by brachial artery flow-mediated dilation (FMD). Healthy individuals (n = 14; age, 18-34 years) performed 30 min of handgrip exercise at fast and slow contractions. Blood pressure during exercise was measured using a Vasotrac system (Medwave Inc.), while shear rate during exercise and FMD at rest and after 30 min of recovery from exercise were measured in the brachial artery of the active arm using Doppler ultrasound. Estimated contractile work was correlated with blood pressure (r = 0.61, p < 0.01) and retrograde shear rate (r = -0.78, p < 0.01). As a result, blood pressure was higher (p < 0.05) and oscillatory shear index was lower (p < 0.05) during slow as compared with fast contractions. On average, FMD was unchanged following fast contractions (5.4 ± 3.4%dilation to 6.1 ± 3.8%dilation; p = 0.19), but significantly reduced following slow contractions (6.9 ± 4.2%dilation to 3.6 ± 2.5%dilation; p = 0.01). Within slow contractions, subgroup analysis revealed blood pressure to associate with the change in FMD; such that individuals with mean blood pressure >100 mm Hg (range, 102-139 mm Hg) during exercise had larger decreases in FMD than individuals with lower exercise blood pressure. These results indicate that impaired local vascular function following acute exercise with high contractile activity is associated with blood pressure stimuli in healthy individuals.
骨骼肌收缩与作用于肌肉血管的物理刺激有关，包括增加切变应力和血压。目前尚不清楚急性动力性运动是否会改变局部血管功能。本研究的目的是研究运动血液动力学在急性运动对血管功能的影响中的作用，肱动脉血流介导的扩张（FMD）评估。健康个体（n=14；年龄 18-34 岁）以快收缩和慢收缩进行 30 分钟的握力运动。使用 Vasotrac 系统（Medwave Inc.）测量运动期间的血压，使用多普勒超声测量主动臂肱动脉在运动期间和运动后 30 分钟恢复期间的切变率和 FMD。估计的收缩功与血压（r=0.61，p<0.01）和逆行切变率（r=-0.78，p<0.01）相关。结果，与快收缩相比，慢收缩时血压更高（p<0.05），振荡切变指数更低（p<0.05）。平均而言，快速收缩后 FMD 无变化（5.4±3.4%扩张至 6.1±3.8%扩张；p=0.19），但慢收缩后显著降低（6.9±4.2%扩张至 3.6±2.5%扩张；p=0.01）。在慢收缩内，亚组分析显示血压与 FMD 的变化相关；即运动期间平均血压>100mmHg（范围 102-139mmHg）的个体的 FMD 降低幅度大于运动时血压较低的个体。这些结果表明，高收缩活性的急性运动后局部血管功能受损与健康个体的血压刺激有关。
