Abstract:
We wanted to determine the influence of total blood volume (BV) and blood lactate quantity on lactate concentrations during incremental exercise. Twenty-six healthy, nonsmoking, heterogeneously trained females (27.5 ± 5.9 ys) performed an incremental cardiopulmonary exercise test on a cycle ergometer during which maximum oxygen uptake (V·O2max), lactate concentrations ([La-]) and hemoglobin concentrations ([Hb]) were determined. Hemoglobin mass and blood volume (BV) were determined using an optimised carbon monoxide-rebreathing method. V·O2max and maximum power (Pmax) ranged between 32 and 62 mL·min-1·kg-1 and 2.3 and 5.5 W·kg-1, respectively. BV ranged between 81 and 121 mL·kg-1 of lean body mass and decreased by 280 ± 115 mL (5.7%, p = 0.001) until Pmax. At Pmax, the [La-] was significantly correlated to the systemic lactate quantity (La-, r = 0.84, p < 0.0001) but also significantly negatively correlated to the BV (r = -0.44, p < 0.05). We calculated that the exercise-induced BV shifts significantly reduced the lactate transport capacity by 10.8% (p < 0.0001). Our results demonstrate that both the total BV and La- have a major influence on the resulting [La-] during dynamic exercise. Moreover, the blood La- transport capacity might be significantly reduced by the shift in plasma volume. We conclude, that the total BV might be another relevant factor in the interpretation of [La-] during a cardio-pulmonary exercise test.
摘要:
我们想确定增量运动过程中总血量(BV)和血乳酸量对乳酸浓度的影响。二十六健康,不吸烟,非均匀训练的女性(27.5±5.9ys)在自行车测功机上进行了增量式心肺运动测试,在此期间最大摄氧量(V·O2max),测定乳酸浓度([La-])和血红蛋白浓度([Hb])。使用优化的一氧化碳再呼吸方法确定血红蛋白质量和血容量(BV)。V·O2max和最大功率(Pmax)分别在32至62mL·min-1·kg-1和2.3和5.5W·kg-1之间。BV在瘦体重的81至121mL·kg-1之间,降低了280±115mL(5.7%,p=0.001)直到Pmax。在Pmax,[La-]与全身乳酸量显著相关(La-,r=0.84,p<0.0001),但与BV也呈显着负相关(r=-0.44,p<0.05)。我们计算得出,运动诱导的BV转移使乳酸转运能力显着降低了10.8%(p<0.0001)。我们的结果表明,在动态运动过程中,总BV和La-对所得的[La-]都有重大影响。此外,血浆容量的变化可能会大大降低血液La转运能力。我们得出结论,在心肺运动试验期间,总BV可能是解释[La-]的另一个相关因素。