Scott Jessica M, Esch Ben T A, Lusina Sarah-Jane C, McKenzie Donald C, Koehle Michael S, Sheel A William, Warburton Darren E R
Cardiovascular Physiology and Rehabilitation Laboratory, University of British Columbia, Vancouver, BC, Canada.
Appl Physiol Nutr Metab. 2008 Apr;33(2):246-53. doi: 10.1139/H07-173.
We tested the hypothesis that following an acute bout of exercise cardiovascular and cerebrovascular responses to lower-body negative pressure (LBNP) would be altered due to post-exercise hypotension (PEH). Ten healthy, male, endurance-trained athletes (mean age +/- SD = 29.6 +/- 5) were assessed for cardiovascular and cerebrovascular responses to LBNP following acute bouts of interval and continuous exercise. Mean arterial pressure (MAP), cardiac output, total peripheral resistance, heart rate variability, and total cerebral oxygen index were determined during a baseline LBNP session. These indices were also determined during two other LBNP sessions: following an acute bout of interval exercise, and following an acute bout of continuous exercise. Compared with baseline, MAP was reduced after both exercise conditions, similar to values previously reported (10 mmHg; p < 0.05 vs. pre-exercise). Total peripheral resistance was significantly reduced following both exercise bouts, and heart rate was significantly increased post-exercise (rest: 59.6 +/- 11.2; interval: 77.8 +/- 12.8; continuous: 80.3 +/- 15.2 beats.min(-1)). Both cardiac output and stroke volume responses to LBNP following exercise were not altered when compared with baseline measurements. Tissue oxygenation during -40 mmHg (interval: 74.31% +/- 7.82% vs. continuous: 69.13% +/- 5.23%) was significantly lower than during normobaric pressure (interval: 77.14% +/- 1.30% vs. continuous: 74.41% +/- 0.94%). It appears from these observations that although young, endurance-trained males experience PEH following acute bouts of interval or continuous exercise, this hypotension does not alter the cardiovascular and cerebrovascular responses to a moderate orthostatic stress.
在进行一轮急性运动后，由于运动后低血压（PEH），对下体负压（LBNP）的心血管和脑血管反应会发生改变。对10名健康的男性耐力训练运动员（平均年龄±标准差 = 29.6±5岁）在进行急性间歇运动和持续运动后，评估其对LBNP的心血管和脑血管反应。在一次基线LBNP测试期间测定平均动脉压（MAP）、心输出量、总外周阻力、心率变异性和总脑氧指数。在另外两次LBNP测试期间也测定了这些指标：一次是在急性间歇运动后，另一次是在急性持续运动后。与基线相比，两种运动条件后MAP均降低，与先前报道的值相似（10 mmHg；与运动前相比，p < 0.05）。两次运动后总外周阻力均显著降低，运动后心率显著增加（静息时：59.6±11.2；间歇运动后：77.8±12.8；持续运动后：80.3±15.2次·分钟⁻¹）。与基线测量值相比，运动后对LBNP的心输出量和每搏输出量反应均未改变。在-40 mmHg时的组织氧合（间歇运动后：74.31%±7.82%，持续运动后：69.13%±5.23%）显著低于常压时（间歇运动后：77.14%±1.30%，持续运动后：74.41%±0.94%）。从这些观察结果来看，尽管年轻的耐力训练男性在急性间歇或持续运动后会出现PEH，但这种低血压并不会改变对中度直立位应激的心血管和脑血管反应。
