The hemorheological abnormalities found in AD patients may be explained by the parallel findings of oxidative damage on erythrocyte membranes that could result in a decrease of erythrocyte deformability. Furthermore, the oxidative stress-induced elevation of fibrinogen concentration could lead to accelerated erythrocyte aggregation as a consequence of a rise in blood viscosity and blood viscoelasticity. Taken together, these factors may impair the oxygen transport efficiency of blood in AD patients.