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ASSOCIATIONS AMONG HEMORHEOLOGICAL FACTORS AND MAXIMAL OXYGEN CONSUMPTION IN AEROBIC AND RESISTANCE ATHLETES

Abstract

M. M. Smith1, A. R. Lucas2, R. L. Hamlin2, & S. T. Devor2

1Gonzaga University, Spokane, WA and 2The Ohio State University, Columbus, OH

Currently, it is not known how hemorheological variables measured in aerobic and resistance athletes compare at rest or following maximal exercise or what influence they may have in determining VO2max. PURPOSE: This study examined the relationship between hematocrit, blood viscosity, plasma viscosity, erythrocyte deformability, and fibrinogen concentration during maximal oxygen uptake in aerobically trained (AT) and resistance trained (RT) athletes. METHODS: Maximal oxygen uptake was assessed using a Bruce graded exercise treadmill test to exhaustion, and blood samples were collected at rest and immediately following exercise using a venous catheter. Viscometric analyses were performed using a cone and plate viscometer at varying shear rates. Hematocrit was measured as the fraction of erythrocytes suspended in plasma following centrifugation. Erythrocyte rigidity was estimated using the Dintenfass index of red blood cell rigidity. RESULTS: Following maximal treadmill exercise, an increase of blood viscosity at varying shear rates (22.50, 45.00, 90.00, and 225.00 s-1; P < 0.05) was observed in RT athletes only. , Plasma viscosity 225.00 s-1 (1.88±0.09 vs. 1.78±0.02 mPa.s; P < 0.05), erythrocyte rigidity (0.52±0.08 vs. 0.40±0.09; P < 0.05), and plasma fibrinogen (295±25 vs. 434±7 mg/dL; P < 0.01) were all significantly greater in RT than AT athletes following maximal exercise. CONCLUSION: In summary, AT, but not RT, is associated with a hemorheological profile that promotes both oxygen transport and delivery. The results bring into question whether hematocrit alone should be the focus of training and ergogenic supplementation to increase aerobic performance.

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