Blood rheology and aging

Abstract

The flow properties of blood play significant roles in tissue perfusion by contributing to hydrod y namic resistance in blood vessels. These properties are influenced by pathophysiological processes, thereby increasing the clinical rel evance of blood rheology information. There is well - established clinical evidence for impaired blood fluidity i n humans of advanced age, including enhanced plasma and whole blood viscosity, impaired red blood cell (RBC) deformability and enhanced RBC aggregation. Increased plasma fibrinogen concentration is a common finding in many studies owing to the pro - inflamma tory condition of aged individuals; this finding of increased fibrinogen conce n- tration explains the higher plasma viscosity and RBC aggregation in elderly subjects. Enhanced oxida nt stress in advanced age is also known to contribute to altered blood fluidi ty, with RBC deformability being an i m portant determinant of blood viscosity. Several studies have shown that physical activity may improve the hemorheological picture in elderly subjects, yet well - designed observational and mechanistic studies are require d to determine the specific effects of regular exercise on hemorheological parameters in healthy and older individuals