LOW VALUES OF BLOOD VISCOSITY AND ERYTHROCYTE AGGREGATION ARE ASSOCIATED WITH LOWER INCREASES IN BLOOD LACTATE DURING SUBMAXIMAL EXERCISE

(Received 13.7.1993; accepted 23.8.1993) Trained sportsmen have low values of blood viscosity (TJb). In this study we tested the functional consequences of this reduction of TJb in 34 sportsmen submitted to a 25 min progressively increasing submaximal work load. A low resting TJb (measured at high shear rate with the MT90 viscometer) was associated to a lower increase in blood lactate during exercise (correlation of llb with: maximal lactate value: r==0.357 p 2.4 mPa.s (with this method) had higher lactate increase (p<0.01) and a deeper decrease in blood bicarbonate (p<0.001). RBC rigidity ('Tk' index) is increased proportionaly to lactate when lactate increases above 4 mmol.l-1. Another group of 21 professional footballers was studied during a maximal triangular work load until V02 max. In this group there was a correlation between maximal lactate response during the test and RBC aggregation (r=0.705 p<0.005). These results suggest that low whole blood viscosity at rest either (a) prevents from excessive lactate increase in this kind of exercise protocol; (b) or is a marker of trained persons characterized by metabolic/circulatory adaptations protecting against exercise-induced hyperlactatemia. In these experimental conditions lower RBC aggregation (within the normal range) seems to be also associated with fitness and lower lactate increase.