1. The relationship between baroreflex sensitivity (BRS) and arterial compliance index (ACI) has been investigated (a) in paired subjects matched in one instance for systolic blood pressure with differing ages, and (b) in another instance matched for age with differing systolic blood pressures.
2. There was a significant negative correlation between BRS and age and between ACI and age in the twelve systolic blood pressure-matched subjects.
3. A significant negative correlation of systolic blood pressure with both BRS and ACI was observed in the fourteen age-matched subjects.
4. Both BRS and ACI appear to decrease with increasing age and systolic blood pressure. This decrease in BRS is probably due at least in part to the observed reduction in arterial distensibility.