Baroreflex sensitivity decreases with age: Data derived from a large population based study
Kardos A., Watterich G., Gingl Z., Csanády M., Casadei B., Rudas L.
Background: Arterial baroreflex sensitivity (BRS) is a tool to assess the prognosis after myocardial infarction. Small studies suggested that BRS (by phenylephrine) declines with age. However, the normal values of the BRS in the population are not known. Objectives: We set out to define the relationship between age and BRS in a large population based study. Methods and Results: Four hundred and twenty healthy subjects (without positive medical history and free of medication) were selected from our database (237 m, 183 f). Subjects were divided into four age-groups; A: 19-29 y (121), B: 30-39 y (111) C: 40-49 y (101) D 50-59 y (87). BRS was evaluated by the slope of spontaneous changes in systolic blood pressure (BP) and R-R interval from 10 minutes BP (Finapres) and ECG recordings. Regression analysis was performed to assess the relationship between BRS and age, and the best fitting curve algorithm was applied (see Figure). Group averages were compared by ANOVA. There was a significant decrease in BRS with age (mean±SD, A: 16.3±7.9, B: 11.9±6.2, C: 8.8±4.8, D: 7.5±3.5 ms/mmHg, p<.05. The difference between group C and D, however was not significant. Males had significantly higher BRS than females in the age group B, whereas, in age group D the BRS was higher in women. In conclusion we demonstrated that non invasive measurements of BRS decrease with age, particularly during the 2nd and 3rd decade. Although male subjects have a higher BRS than females in young age, this pattern is reversed in middle-age. In view of its large size, our study is the first to provide reference values for the non invasive measurement of BRS in healthy subjects. (Graph Presented).