Changes in Blood Rheology Produced by Exercise

Abstract

<h3>To the Editor.—</h3> The recent Olympic issue ofThe Journalwhich focused on cardiovascular and medical aspects of exercise provided information of unique value. Briefly, it wassuggested that different forms of training are associated with favorable changes in lipoprotein patterns'^1,2and that exercise level predicts cardiovascular risk.^3,4Our own group has investigated the effects of exercise on blood rheology. We studied a group of first-league soccer players, comparing them with age-matched sedentary persons (Table 1). We observed hemorrheological changes during a three-month vigorous training program (mean, four hours intensive exercise per day, seven days a week) in formerly sedentary volunteers (Table 2). The variables tested were blood and plasma viscosity,^5,6hematocrit red cell deformability,⁷and red cell aggregation. In the interindividual comparison we saw significant differences in plasma viscosity and red cell deformability, implying enhanced blood fluidity in athletes (Table 1); in the intraindividual comparison,