Respiratory muscle work compromises leg blood flow during maximal exercise
Respiratory muscle work compromises leg blood flow during maximal exercise
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DOI：
10.1152/jappl.1997.82.5.1573
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发表时间：
1997-05-01
影响因子：
3.3
通讯作者：
Dempsey, JA
中科院分区：
文献类型：
--
作者：
Harms, CA;Babcock, MA;Dempsey, JA
我们假设，在最大氧消耗（（V）超过dotO（2 max））的运动过程中，对呼吸肌血流的高需求（（Q）超过dot）将引起运动肌血管收缩并损害肢体（Q）超过dot。七名男性自行车运动员（（V）超过dot 0（2 max）64 +/- 6 ml.kg（-1）.min（-1））在两次测试期间，在自行车测力计上以（V）超过dot 0（2 max）完成了14次持续时间为2.5分钟的运动。吸气肌功要么1）通过比例辅助呼吸机减少，要么2）通过分级阻力负荷增加，要么3）不受操纵（对照）。测量动脉（肱动脉）和静脉（股动脉）血液样本、动脉血压、腿部（Q）对点（（Q）对点腿;热稀释法）、食管压力和Oz消耗量（（V）对点O（2））。在每个受试者和所有受试者中，在恒定的最大作功率下，呼吸功（Wb）和（Q）在点腿上（反向）、腿部血管阻力（LVR）和腿（V）在点O（2）上（（V）在点O（2腿）上;反向）之间存在显著相关性（r = 0.74-0.90; P < 0.05），LVR和去甲肾上腺素溢出之间存在显著相关性（r = 0.74-0.90; P < 0.05）。平均动脉压不随Wb的变化而变化，潮气量或每分钟通气量也不随Wb的变化而变化。对于Wb相对于对照的+/-50%变化，（Q）在dotlegs上变化2 l/min或对照的11%，LVR变化对照的13%，O-2提取没有变化;因此（V）在dotO（2legs）上变化0.4 l/min或对照的10%。总（V）超过dotO-2 max与负荷不变，但与卸载下降9.3%;因此（V）超过dotO（2条腿）占总（V）超过dotO（2 max）的百分比在对照组中为81%，在呼吸肌卸载时增加至89%，在呼吸肌负荷时下降至71%。我们的结论是，在最大运动期间通常引起的Wb导致运动肌肉中的血管收缩，并损害运动肌肉灌注和（V）超过dotO（2）。
We hypothesized that during exercise at maximal O-2 consumption ((V) over dotO(2max)), high demand for respiratory muscle blood flow ((Q) over dot) would elicit locomotor muscle vasoconstriction and compromise limb (Q) over dot. Seven male cyclists ((V) over dotO(2max) 64 +/- 6 ml.kg(-1).min(-1)) each completed 14 exercise bouts of 2.5-min duration at (V) over dotO(2max) on a cycle ergometer during two testing sessions. Inspiratory muscle work was either 1) reduced via a proportional-assist ventilator, 2) increased via graded resistive loads, or 3) was not manipulated (control). Arterial (brachial) and venous (femoral) blood samples, arterial blood pressure, leg (Q) over dot ((Q) over dotlegs; thermodilution), esophageal pressure, and Oz consumption ((V) over dotO(2)) were measured. Within each subject and across all subjects, at constant maximal work rate, significant correlations existed (r = 0.74-0.90; P < 0.05) between work of breathing (Wb) and (Q) over dotlegs (inverse), leg vascular resistance (LVR), and leg (V) over dotO(2) ((V) over dotO(2legs); inverse), and between LVR and norepinephrine spillover. Mean arterial pressure did not change with changes in Wb nor did tidal volume or minute ventilation. For a +/-50% change from control in Wb, (Q) over dotlegs changed 2 l/min or 11% of control, LVR changed 13% of control, and O-2 extraction did not change; thus (V) over dotO(2legs) changed 0.4 l/min or 10% of control. Total (V) over dot O-2max was unchanged with loading but fell 9.3% with unloading; thus (V) over dotO(2legs) as a percentage of total (V) over dotO(2max) was 81% in control, increased to 89% with respiratory muscle unloading, and decreased to 71% with respiratory muscle loading. We conclude that Wb normally incurred during maximal exercise causes vasoconstriction in locomotor muscles and compromises locomotor muscle perfusion and (V) over dotO(2).