Brun Jean-Frédéric, Varlet-Marie Emmanuelle, Raynaud de Mauverger Eric
UMR CNRS 9214-Inserm U1046 ⪡ Physiopathologie & Médecine Expérimentale du Cœur etdes Muscles - PHYMEDEXP ⪢, Unité d'Explorations Métaboliques (CERAMM), Université de Montpellier, Département de Physiologie Clinique, Hôpital Lapeyronie CHU Montpellier, France.
Institut des Biomolécules Max Mousseron (IBMM) UMR CNRS 5247, Université de Montpellier, Ecole Nationale Supérieure de Chimie de Montpellier, France.
Clin Hemorheol Microcirc. 2016;64(4):777-787. doi: 10.3233/CH-168012.
The hemorheological theory of optimal hematocrit suggests that the best value of hematocrit (hct) should be that which results in the highest value of the hematocrit/viscosity (h/η) ratio. Trained athletes compared to sedentary subjects have a lower hct, but a higher h/η, and endurance training reduces the discrepancy between the actual hct and the ⪡ideal⪢ hct that can be predicted with a theoretical curve of h/η vs hct constructed with Quemada's model. In this study we investigated what becomes this homeostasis of h/η and hct during acute exercise in 19 athletes performing a 25 min exercise test. VO2max is negatively correlated to resting hct and positively correlated to discrepancy between actual and ideal resting hct which is correlated to the maximal rise in hct during exercise. Predicted and actual values of the h/η were fairly correlated (r = 0.970 p < 0.001) but the actual value was lower at rest and this discrepancy vanished at 25 min exercise. Exercise-induced decrease in discrepancy between actual and theoretical h/η was negatively correlated with the score of overtraining. All these findings suggest that h/η is a regulated parameter and that its model-predicted ⪡optimal⪢ values yield a ⪡theoretical optimal⪢ hct which is close to the actual value and even closer when athletes are well trained. In addition, acute exercise sets h/η closer from its predicted ideal value and this adaptation is impaired when athletes quote elevated scores on the overtraining questionnaire.
最佳血细胞比容的血液流变学理论表明，血细胞比容（hct）的最佳值应是能使血细胞比容/黏度（h/η）比值达到最高的值。与久坐不动的人相比，经过训练的运动员血细胞比容较低，但h/η较高，耐力训练可减少实际血细胞比容与通过用凯马达模型构建的h/η与血细胞比容理论曲线预测的“理想”血细胞比容之间的差异。在本研究中，我们调查了19名运动员在进行25分钟运动测试的急性运动过程中，h/η和血细胞比容的这种内稳态会发生什么变化。最大摄氧量（VO2max）与静息血细胞比容呈负相关，与实际静息血细胞比容和理想静息血细胞比容之间的差异呈正相关，而这种差异与运动过程中血细胞比容的最大升高相关。h/η的预测值和实际值具有相当高的相关性（r = 0.970，p < 0.001），但静息时实际值较低，这种差异在运动25分钟时消失。运动引起的实际h/η与理论h/η之间差异的减小与过度训练评分呈负相关。所有这些发现表明，h/η是一个受调节的参数，其模型预测的“最佳”值产生一个“理论最佳”血细胞比容，该值接近实际值，当运动员训练良好时甚至更接近。此外，急性运动使h/η更接近其预测的理想值，而当运动员在过度训练问卷上的得分较高时，这种适应性会受到损害。
