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The mean red cell volume in long distance runners

M Stäubli, B Roessler

    European Journal of Applied Physiology and Occupational Physiology
    |January 1, 1986
    PubMed

    Insights

    Endurance running alters red blood cell indices. Red cell volume regulation after a 100 km race may involve factors beyond plasma osmolality, potentially maintaining blood viscosity.

    Area of Science:

    • Exercise Physiology
    • Hematology
    • Sports Medicine

    Background:

    • Red blood cell (RBC) indices are crucial for oxygen transport and blood viscosity.
    • Endurance running, particularly ultra-marathons, can induce significant physiological stress.
    • Understanding RBC volume regulation during and after prolonged exercise is important for athlete health and performance.

    Purpose of the Study:

    • To investigate changes in red cell indices in trained runners after a 100 km race.
    • To compare Coulter Counter (CC) derived indices with calculated values from centrifuged hematocrit (ctrf).
    • To explore the role of plasma osmolality in regulating red cell volume post-exercise.

    Main Methods:

    • Determination of red cell indices in 6 trained runners before and after a 100 km race.
    • Comparison of Coulter Counter (CC) measurements with calculated values from centrifuged hematocrit (ctrf), RBC count, and hemoglobin.
    • Analysis of changes in mean corpuscular volume (MCV) and mean corpuscular hemoglobin concentration (MCHC).

    Main Results:

    • Mean corpuscular volume (MCV) determined by centrifugation (MCV(ctrf)) decreased by 4.9% (p<0.001).
    • Mean corpuscular volume (MCV) determined by Coulter Counter (MCV(CC)) increased by 1.9% (p<0.05).
    • Mean corpuscular hemoglobin concentration (MCHC) showed opposing trends: MCHC(ctrf) increased by 4%, while MCHC(CC) decreased by 3%.

    Conclusions:

    • The increase in MCV(CC) suggests increased intraerythrocyte osmolality and cell swelling due to water shift into RBCs.
    • The decrease in MCV(ctrf) was not directly correlated with plasma osmolality, indicating other regulatory factors.
    • RBC volume changes post-race may be a physiological mechanism to maintain favorable blood viscosity and hematocrit.

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