• DOI:10.1152/AJPREGU.1996.271.4.R1078
• Corpus ID: 11159872

Age-related alterations in the fractal scaling of cardiac interbeat interval dynamics.

@article{Iyengar1996AgerelatedAI,
  title={Age-related alterations in the fractal scaling of cardiac interbeat interval dynamics.},
  author={Nikhil Iyengar and Chung-Kang Peng and Raymond J. Morin and Ary L. Goldberger and Lewis A. Lipsitz},
  journal={The American journal of physiology},
  year={1996},
  volume={271 4 Pt 2},
  pages={
          R1078-84
        }
}

• N. Iyengar, Chung-Kang Peng, +2 authors L. Lipsitz
• Published 1 October 1996
• Medicine
• The American journal of physiology

We postulated that aging is associated with disruption in the fractallike long-range correlations that characterize healthy sinus rhythm cardiac interval dynamics. Ten young (21-34 yr) and 10 elderly (68-81 yr) rigorously screened healthy subjects underwent 120 min of continuous supine resting electrocardiographic recording. We analyzed the interbeat interval time series using standard time and frequency domain statistics and using a fractal measure, detrended fluctuation analysis, to quantify long-range correlation properties. In healthy young subjects, interbeat intervals demonstrated fractal scaling, with scaling exponents (alpha) from the fluctuation analysis close to a value of 1.0. In the group of healthy elderly subjects, the interbeat interval time series had two scaling regions. Over the short range, interbeat interval fluctuations resembled a random walk process (Brownian noise, alpha = 1.5), whereas over the longer range they resembled white noise (alpha = 0.5). Short (alpha s)- and long-range (alpha 1) scaling exponents were significantly different in the elderly subjects compared with young (alpha s = 1.12 +/- 0.19 vs. 0.90 +/- 0.14, respectively, P = 0.009; alpha 1 = 0.75 +/- 0.17 vs. 0.99 +/- 0.10, respectively, P = 0.002). The crossover behavior from one scaling region to another could be modeled as a first-order autoregressive process, which closely fit the data from four elderly subjects. This implies that a single characteristic time scale may be dominating heartbeat control in these subjects. The age-related loss of fractal organization in heartbeat dynamics may reflect the degradation of integrated physiological regulatory systems and may impair an individual's ability to adapt to stress.