title: Reproducibility of heart rate variability, blood pressure variability and baroreceptor sensitivity during rest and head-up tilt.
abstract: OBJECTIVE
  Previous studies have indicated moderate-to-poor reproducibility of heart rate variability (HRV) but the reproducibility of blood pressure variability (BPV) and spectral measures of baroreceptor sensitivity (BRS) are not well established.
  
  
  METHODS
  We measured normal-to-normal heart beat (RR) interval and finger blood pressure (Finapres) in 14 healthy individuals on three different days. The protocol was 1 h of supine rest and 1 h of 60-degree head-up tilt. Time-series of consecutive 300-s segments as well as 1024-s segments of RR intervals and systolic, diastolic and mean blood pressures were extracted for the assessment of day-to-day and short-term reproducibility. Power spectrum analysis (Fourier) and transfer function analysis was performed. Reproducibility was assessed using the coefficient of variation (CV). The reproducibility of the mean RR interval, mean systolic, diastolic and mean blood pressure was good (CV<10 %). However, there was only moderate-to-poor reproducibility of the spectral parameters of HRV (CV range 18-36%) and BPV (16-44%) and moderate reproducibility of BRS (14-20%).
  
  
  CONCLUSIONS
  Spectral estimates of BRS had only moderate reproducibility although it was better than the spectral estimates of HRV and BPV.
authors.affiliation: Laboratory for Experimental Cardiology, University of Copenhagen, Copenhagen, Denmark. mvhojgaard@dadlnet.dk
authors.forename: Michael V
authors.initials: MV
authors.lastname: Højgaard
authors.forename: Niels-Henrik
authors.initials: NH
authors.lastname: Holstein-Rathlou
authors.forename: Erik
authors.initials: E
authors.lastname: Agner
authors.forename: Jørgen K
authors.initials: JK
authors.lastname: Kanters
mesh_terms: D000328:Adult; D017704:Baroreflex; D001794:Blood Pressure; D006339:Heart Rate; D006801:Humans; D011187:Posture; D012016:Reference Values; D015203:Reproducibility of Results; D012146:Rest; D016008:Statistical Distributions