Vol. 276, Issue 6, H2188-H2193, June 1999
Greater erythrocyte deformability in world-class endurance
athletes
John A.
Smith1,
David T.
Martin2,
Richard D.
Telford3, and
Samir K.
Ballas4
1 Department of Physical
Therapy, Tennessee State University, Nashville, Tennessee 37209-1561;
2 Department of Physiology and
Applied Nutrition, Australian Institute of Sport, Belconnen, ACT 2616, Australia; 3 School of Exercise
Science, Griffith University, Gold Coast Campus 4017 QLD, Australia;
and 4 Cardeza Foundation for
Hematologic Research, Department of Medicine, Thomas Jefferson
University, Philadelphia, Pennsylvania 19107
Because athletes
during endurance events require rapid uptake of oxygen, the ability of
red blood cells (RBC) to move through capillaries may limit
performance. Using ektacytometry, we determined whether RBC
deformability (RCD) differed between elite road cyclists (n = 9) and sedentary controls
(n = 5). Density profiles and standard hematological measurements were also performed. The deformability index
(DI) was higher in the cyclists (0.723 ± 0.027) compared with that
in controls (0.619 ± 0.040, P < 0.001). Cyclists also had a
larger percentage of low-density RBCs
(P < 0.001), and mean cell volume
(MCV) was also higher (P = 0.013).
These findings are indicative of a larger proportion of "young"
RBCs in the blood of elite cyclists and provide further evidence that
the turnover of RBCs in endurance athletes is higher than in the
general population. With a younger more deformable RBC population and
providing the destruction does not exceed replacement, performance
potential should be enhanced. Furthermore, examination of factors that
contribute to increased RBC turnover in athletes may help us understand
the mechanisms that cause RBC aging.
red blood cells; exercise; hematology; blood flow
