title: Can we detect the development of baroreflex sensitivity in humans between 11 and 20 years of age?
abstract: The aim of the study was to determine changes of baroreflex sensitivity in humans between 11 and 20 years of age. Continuous 5 min blood pressure recordings using a Finapres were taken in 415 healthy subjects while in a sitting, resting position (breathing at a frequency of 0.33 Hz). Beat-by-beat values of interbeat intervals (IBI) or heart rate, and systolic and diastolic blood pressures were measured. Baroreflex sensitivity in ms/mmHg (BRS) and in mHz/mmHg (BRSf) was determined at an average frequency of 0.1 Hz by spectral analysis. BRS did not correlate with age, but BRSf significantly decreased with age (p < 0.001). BRS correlated with mean IBI (p < 0.001) in all subjects and also in the particular subgroups, but BRSf was IBI-independent. Results of multiregression equations were BRS = 1.37 - 0.56 x age (years) + 0.02 x IBI (ms) (p < 0.001 for BRS vs. age and for BRS vs. IBI); BRSf = 34.74 - 0.97 x age (years) - 0.001 x IBI (ms) (p < 0.001 only for BRS vs. age), where age was measured in years and IBI was measured in ms. The limits of BRS were estimated for the total group: 5th percentile, 3.9; 50th percentile, 9.1; and 95th percentile, 18.7 ms/mmHg; and limits for BRSf were 5th percentile, 8.5; 50th percentile, 16.4; and 95th percentile, 33.6 mHz/mmHg. We conclude that IBI-dependent BRS was unchanged in the particular age groups, but the standardization of BRS on IBI decreased with age. BRSf was IBI-independent and better reflected the development of the BRS.
authors.affiliation: Department of Physiology, Faculty of Medicine, Masaryk University, Komenskeho nam. 2, CZ-662 43 Brno, Czech Republic. ezavod@med.muni.cz
authors.forename: Eva
authors.initials: E
authors.lastname: Zavodna
authors.forename: Natasa
authors.initials: N
authors.lastname: Honzikova
authors.forename: Hana
authors.initials: H
authors.lastname: Hrstkova
authors.forename: Zuzana
authors.initials: Z
authors.lastname: Novakova
authors.forename: Jiri
authors.initials: J
authors.lastname: Moudr
authors.forename: Miroslav
authors.initials: M
authors.lastname: Jira
authors.forename: Bohumil
authors.initials: B
authors.lastname: Fiser
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000367:Age Factors; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure; D002648:Child; D018153:Czech Republic; D005260:Female; D005385:Fingers / Q000098:blood supply*; D006339:Heart Rate; D006801:Humans; D008297:Male; D008955:Models, Cardiovascular; D012044:Regression Analysis