title: Correlation differences in heartbeat fluctuations during rest and exercise.
abstract: We study the heartbeat activity of healthy individuals at rest and during exercise. We focus on correlation properties of the intervals formed by successive peaks in the pulse wave and find significant scaling differences between rest and exercise. For exercise the interval series is anticorrelated at short-time scales and correlated at intermediate-time scales, while for rest we observe the opposite crossover pattern--from strong correlations in the short-time regime to weaker correlations at larger scales. We also suggest a physiologically motivated stochastic scenario to provide an intuitive explanation of the scaling differences between rest and exercise.
authors.affiliation: Department of Physics and Gonda-Goldschmied Medical Diagnostic Research Center, Bar-Ilan University, Ramat-Gan 52900, Israel.
authors.forename: Roman
authors.initials: R
authors.lastname: Karasik
authors.forename: Nir
authors.initials: N
authors.lastname: Sapir
authors.forename: Yosef
authors.initials: Y
authors.lastname: Ashkenazy
authors.forename: Plamen Ch
authors.initials: PCh
authors.lastname: Ivanov
authors.forename: Itzhak
authors.initials: I
authors.lastname: Dvir
authors.forename: Peretz
authors.initials: P
authors.lastname: Lavie
authors.forename: Shlomo
authors.initials: S
authors.lastname: Havlin
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D015444:Exercise; D005080:Exercise Test; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D005082:Physical Exertion; D013997:Time Factors