Stöcker F, Von Oldershausen C, Paternoster F K, Schulz T, Oberhoffer R
Center for Teaching and Learning, Technical University Munich, Munich, Germany.
Department for Biomechanics in Sports, Technical University Munich, Munich, Germany.
Clin Physiol Funct Imaging. 2018 May;38(3):431-438. doi: 10.1111/cpf.12434. Epub 2017 Apr 26.
Blood flow (BF) in exercising muscles is an important factor for exercise capacity. Recently, a non-invasive method to estimate capillary BF (Q ) was introduced. Using this method, the Fick principle is re-arranged by using relative differences in deoxygenated haemoglobin (ΔHHb) as a surrogate for arteriovenous O difference and pulmonary oxygen uptake (VO ) instead of muscular oxygen uptake. The aim of this study was to examine (I) the relationship between Q and exercise intensity during and following exercise, and (II) to critically reflect the Q approach. Seventeen male subjects completed six bouts of cycling exercise with different exercise intensities (40-90% peak oxygen uptake, VO ) in randomized order. VO and ΔHHb were monitored continuously during the trail. Q was modelled bi-exponentially, and mean response time (MRT) was calculated during recovery as well as the dissociation of modelled VO and Q recovery kinetics (MRT/τVO ). End-exercise Q increased continuously with exercise intensity. This also applied to MRT. Postexercise MRT/τVO increased from 40 to 60% VO but remained stable thereafter. The results show that Q response to exercise is linearly related to exercise intensity. This is presumably due to vasoactive factors like shear-stress or endothelial-mediated vasodilation. MRT/τVO shows that postexercise Q is elevated for a longer period than VO , which is representative for metabolic demand following exercise ≥70% VO . This is a hint for prolonged local vasodilation. According to previous studies, Q could not be modelled properly in some cases, which is a limitation to the method and therefore has to be interpreted with caution.
运动肌肉中的血流量（BF）是影响运动能力的一个重要因素。最近，一种估计毛细血管血流量（Q）的非侵入性方法被引入。使用这种方法，通过利用脱氧血红蛋白的相对差异（ΔHHb）作为动静脉氧差的替代指标，以及肺摄氧量（VO）而非肌肉摄氧量，对菲克原理进行了重新整理。本研究的目的是检验：（I）运动期间及运动后Q与运动强度之间的关系；（II）批判性地反思Q方法。17名男性受试者以随机顺序完成了六组不同运动强度（40 - 90%最大摄氧量，VO）的自行车运动。在试验过程中持续监测VO和ΔHHb。Q采用双指数模型进行模拟，并计算恢复过程中的平均反应时间（MRT）以及模拟的VO和Q恢复动力学的解离度（MRT/τVO）。运动结束时的Q随运动强度持续增加。这也适用于MRT。运动后MRT/τVO从40%VO增加到60%VO，但此后保持稳定。结果表明，Q对运动的反应与运动强度呈线性相关。这可能是由于剪切应力或内皮介导的血管舒张等血管活性因素所致。MRT/τVO表明，运动后Q升高的时间比VO长，对于运动强度≥70%VO后的代谢需求具有代表性。这提示存在局部血管舒张延长的情况。根据先前的研究，在某些情况下Q无法得到恰当的模拟，这是该方法的一个局限性，因此必须谨慎解释。
