Polycythemia, viscosity and blood flow in working and non-working skeletal muscle in the dog

The relationship between hematocrit and blood flow in the vasodilated working and non-working skeletal muscle at different perfusion pressures was studied. After acutely induced polycythemia in the flow decreased by 35% in the non-working muscle which was proportional to the increase of viscosity measured in vitro. In the working muscle there was only a small non-significant decrease of flow after polycythemia indicating flow improvement at increased hematocrit by rhythmic muscle contractions.