Increase in blood viscosity due to alcohol drinking.

To elucidate the effects of alcohol on thrombotic diseases we focussed on blood rheology which is one of the most important factors of blood flow. We measured the viscosity of whole blood and plasma of 18 healthy volunteers (11 males and 7 females) before and after drinking at a dinner party. There were significant increases in whole blood viscosity (7.4%, P less than 0.005) and plasma viscosity (3.0%, P less than 0.005) after drinking. Judging from the significant correlations between changes in blood viscosity and changes in variables related to hemoconcentration, the ability of alcohol to increase blood viscosity is considered to be due mainly to hemoconcentration. Alcohol itself did not increase whole blood viscosity in vitro at concentrations of 0.1, 0.2, 0.3 and 0.4% (w/v).