期刊
AMERICAN JOURNAL OF PHYSIOLOGY-HEART AND CIRCULATORY PHYSIOLOGY
卷 292, 期 5, 页码 H2491-H2497出版社
AMER PHYSIOLOGICAL SOC
DOI: 10.1152/ajpheart.01396.2006
关键词
exercise; blood flow; vasodilatory reserve
资金
- NHLBI NIH HHS [HL 17731] Funding Source: Medline
To further explore the limitations to maximal O-2 consumption (VO2max) in exercise-trained skeletal muscle, six cyclists performed graded knee-extensor exercise to maximum work rate (WRmax) in hypoxia (12% O-2), hyperoxia (100% O-2), and hyperoxia + femoral arterial infusion of adenosine (ADO) at 80% WRmax. Arterial and venous blood sampling and thermodilution blood flow measurements allowed the determination of muscle O-2 delivery and O-2 consumption. At WRmax, O-2 delivery rose progressively from hypoxia (1.0 +/- 0.04 l/min) to hyperoxia (1.20 +/- 0.09 l/min) and hyperoxia + ADO (1.33 +/- 0.05 l/min). Leg VO2max-varied with O-2 availability (0.81 +/- 0.05 and 0.97 +/- 0.07 l/min in hypoxia and hyperoxia, respectively) but did not improve with ADO-mediated vasodilation (0.80 +/- 0.09 l/min in hyperoxia + ADO). Although a vasodilatory reserve in the maximally working quadriceps muscle group may have been evidenced by increased leg vascular conductance after ADO infusion beyond that observed in hyperoxia (increased blood flow but no change in blood pressure), we recognize the possibility that the ADO infusion may have provoked vasodilation in nonexercising tissue of this limb. Together, these findings imply that maximally exercising skeletal muscle may maintain some vasodilatory capacity, but the lack of improvement in leg VO2max with significantly increased O-2 delivery (hyperoxia + ADO), with a degree of uncertainty as to the site of this dilation, suggests an ADO-induced mismatch between O-2 consumption and blood flow in the exercising limb.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据