title: Phase transition in a healthy human heart rate.
abstract: A healthy human heart rate displays complex fluctuations which share characteristics of physical systems in a critical state. We demonstrate that the human heart rate in healthy individuals undergoes a dramatic breakdown of criticality characteristics, reminiscent of continuous second order phase transitions. By studying the germane determinants, we show that the hallmark of criticality--highly correlated fluctuations--is observed only during usual daily activity, and a breakdown of these characteristics occurs in prolonged, strenuous exercise and sleep. This finding is the first reported discovery of the dynamical phase transition phenomenon in a biological control system and will be a key to understanding the heart rate control system in health and disease.
authors.affiliation: Educational Physiology Laboratory, Graduate School of Education, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Kiyono
authors.forename: Zbigniew R
authors.initials: ZR
authors.lastname: Struzik
authors.forename: Naoko
authors.initials: N
authors.lastname: Aoyagi
authors.forename: Fumiharu
authors.initials: F
authors.lastname: Togo
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Yamamoto
mesh_terms: D000328:Adult; D000465:Algorithms; D002940:Circadian Rhythm / Q000502:physiology*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D005246:Feedback / Q000502:physiology; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008955:Models, Cardiovascular; D015233:Models, Statistical; D012016:Reference Values