Letcher R L, Pickering T G, Chien S, Laragh J H
Clin Cardiol. 1981 Jul-Aug;4(4):172-9. doi: 10.1002/clc.4960040405.
To assess the immediate and long-term effects of exercise on factors regulating blood flow, we measured plasma viscosity (eta p) and plasma renin activity (PRA) in 17 trained runners and 16 sedentary healthy subjects before and 10 min after graded treadmill exercise. Resting eta p was lower in runners primarily because of significantly lower fibrinogen concentration. Compared to nonrunners with similar 24-h urine electrolyte excretion rates, runners were characterized by lower PRA at rest. In view of the overall correlation between heart rate and PRA before exercise, reduced adrenergic tone was probably a major factor contributing to the lower PRA in runners. After exercise, plasma viscosity and PRA exceeded control levels, and were similar in magnitude in runners and sedentary subjects. Changes in plasma viscosity were less than expected from the degree of hemoconcentration, primarily because enhanced fibrinolysis maintained fibrinogen level constant. To the extent that plasma viscosity affects viscous flow resistance, the results suggest that tissue perfusion and oxygen delivery rate at rest are greater in trained runners than in sedentary subjects, but these variables become similar after maximum exertion.
为了评估运动对调节血流的因素的即时和长期影响，我们在17名训练有素的跑步者和16名久坐不动的健康受试者进行分级跑步机运动前及运动后10分钟，测量了血浆粘度（ηp）和血浆肾素活性（PRA）。跑步者静息时的ηp较低，主要是因为纤维蛋白原浓度显著较低。与24小时尿电解质排泄率相似的非跑步者相比，跑步者静息时的PRA较低。鉴于运动前心率与PRA之间的总体相关性，肾上腺素能张力降低可能是跑步者PRA较低的主要因素。运动后，血浆粘度和PRA超过对照水平，跑步者和久坐受试者的升高幅度相似。血浆粘度的变化小于根据血液浓缩程度预期的变化，主要是因为纤维蛋白溶解增强使纤维蛋白原水平保持恒定。就血浆粘度影响粘性流动阻力而言，结果表明，训练有素的跑步者静息时的组织灌注和氧气输送率高于久坐不动的受试者，但在最大运动后这些变量变得相似。
