Heart Rate Variability (HRV) has been studied
in a variety of clinical situations in order to quantify the modulations
in the heart rate associated to different pathological
conditions. Nevertheless, significant changes in spectral and
some nonlinear parameters of the HRV were reported also in
normal subjects, depending on age and gender. The aim of this
work was to quantify the age-related differences in other nonlinear
parameters, particularly in the fractal dimension, of the
HRV of healthy subjects and to compare the results with the
changes showed by spectral measures. The RR time series
extracted by the Holter monitoring of 60 healthy subjects,
divided into three groups similar for both age and gender,
were accurately analyzed. The results only partially revealed
age-related changes both in the spectral and fractal HRV
measures, underlining the need to carefully examine the RR
data selection and the pre-processing phases.
