title: A nonlinear explanation of aging-induced changes in heartbeat dynamics.
abstract: The possibility of computing a cardiac age on the basis of spectral analysis of healthy individual tachograms was confirmed and facilitated by the use of a nonlinear technique: recurrence quantification analysis. The age of 112 subjects was predicted by this technique in terms of a progressive increase in the deterministic character of the heartbeat. This result confirms the "random-walk" character of the heartbeat as predicted by the terminal dynamics paradigm, thus allowing for a simple and comprehensive model of the effect of aging on cardiac dynamics: as age progresses, heart rate dynamics become increasingly predictable (constrained) on a beat-to-beat basis. This implies a basically stochastic nature of heart rate dynamics, probably reflecting the continuous adjustments to an unpredictable internal environment.
authors.affiliation: Istituto Superiore di Sanità, Laboratory of Comparative Toxicology and Ecotoxicology, 00161 Rome, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Giuliani
authors.forename: G
authors.initials: G
authors.lastname: Piccirillo
authors.forename: V
authors.initials: V
authors.lastname: Marigliano
authors.forename: A
authors.initials: A
authors.lastname: Colosimo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D003198:Computer Simulation; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008875:Middle Aged; D012016:Reference Values