Hemorheological changes during human aging.

Various researchers have reported an association of hemorheological, hematological and metabolic changes with human aging. In this article an attempt has been made to review the present understanding of hemorheological changes and their probable role in the development of certain disorders/diseases during aging. The rise in fibrinogen, blood viscosity, plasma viscosity, red cell rigidity, fibrin degradation products and early activation of the coagulation system are some of the most prominent findings. It is generally agreed that a rise in blood viscosity factors leads to a state of hypoperfusion which results in impaired microcirculation. The cumulative effect of these changes appears in the form of a disturbed blood flow profile in older subjects leading to the development or aggravation of various circulatory disorders. Many studies indicate that hemorheological parameters that change in a number of diseases prevalent during aging include hypertension, stroke, diabetes. In addition correlations found between hemorheological parameters in the aged and decrements in certain cognitive functions and behavioral patterns suggest that hemorheological changes contribute to nonclinical aging changes.