Skeletal Muscle Perfusion, Exercise Capacity, and the Optimal Hematocrit
The concentration of red cells in the blood is the most important determinant of apparent blood viscosity and therefore one of the determinants of tissue perfusion. Even if it is known that alterations of hematocrit due to their influence on blood viscosity lead to changes of blood flow through various organs, it is not clear to what extent the distribution of flow within the microcirculation is affected by such changes. Therefore it is not directly possible to estimate the optimal level of hematocrit at which O2 delivery to the tissue cells is maximal. Experimentally, this optimal hematocrit (H opt) was found to be lower than the physiologic hematocrit level under resting conditions (6); these observations have led to the therapeutic concept of hemodilution as a means to improve the nutritive supply of the tissues.
KeywordsExercise Capacity Blood Viscosity Perfuse Blood Hematocrit Level Muscle Blood Flow
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