AGE-RELATED DIFFERENCES IN ELASTIC PROPERTIES OF THE UPPER ARM VASCULAR BED IN HEALTHY-ADULTS

The significance of age-related changes in arterial stiffness has rema ined largely uncertain in healthy subjects. This appears to be partly due to difficulties in the interpretation of methods for measuring art erial stiffness in vivo. Therefore, a recently developed electrical bi oimpedance method was used for Distensibility studying elastic propert ies of a vascular bed as a function of age. In 66 healthy Hypertension subjects, aged 22-82 years, we investigated the vascular bed of an up per arm segment. This vascular bed showed an age-related decrease in t he venous blood volume (r = -0.31, p < 0.01) and in the distensibility , the inverse of stiffness, of the larger arteries (r = -0.38, p < 0.0 01). The distensibility of the arterial bed as a whole at normotensive blood pressure, however, appeared to increase with age (r = 0.32, p < 0.005). The arterial and venous blood volumes, arterial compliance an d extravascular fluid volume were significantly higher in the males th an in the females. Practically all investigated vascular properties ap peared to be related with height, body mass or body mass index. We con cluded that comparative studies concerning vascular properties should preferably be performed in subjects matched as to age, gender, height and body mass. In healthy subjects the smaller arteries adjust to the age-related decrease in large artery distensibility by means of an age -related increase in distensibility. These age-related changes in arte rial distensibility are caused by changes in the females, and seem to be associated with age-related changes in body mass index rather than with aging per se.