[Rheological characteristics of the blood in long-term and quick adaptation to muscle loads].

It was established in chronic experiments on 26 dogs that long-term adaptation to regular muscular activity caused a 19.6-46.1% decrease in blood viscosity. Hematocrit was lowered and red cell deformability improved. A correlation was observed between blood viscosity and its oxygen transport function. As a result of muscular training the role of plasma protein in blood viscosity increased and that of red cells declined. Single muscular activity produced a 48.2-81% increase in blood viscosity, while plasma viscosity remained unchanged. Trained animals had lower absolute values of blood viscosity even at the time of muscular effort as compared to those in untrained animals at rest.