Nunes Amaral, Luis A.Ivanov, Plamen Ch.Aoyagi, NaokoHidaka, IchiroTomono, ShinjiGoldberger, Ary L.Stanley, H. E.Yamamoto, Yoshiharu2020-03-272020-03-272001-06-25L.A.N. Amaral, P.C. Ivanov, N. Aoyagi, I. Hidaka, S. Tomono, A.L. Goldberger, H.E. Stanley, Y. Yamamoto. 2001. "Behavioral-independence features of complex heartbeat dynamics."Physical Review Letters, Volume 86, Issue 26, pp. 6026 - 6029. https://doi.org/10.1103/PhysRevLett.86.60260031-9007https://hdl.handle.net/2144/39848We test whether the complexity of cardiac interbeat interval time series is simply a consequence of the wide range of scales characterizing human behavior, especially physical activity, by analyzing data taken from healthy adult subjects under three conditions with controls: (i) a “constant routine” protocol where physical activity and postural changes are kept to a minimum, (ii) sympathetic blockade, and (iii) parasympathetic blockade. We find that when fluctuations in physical activity and other behavioral modifiers are minimized, a remarkable level of complexity of heartbeat dynamics remains, while for neuroautonomic blockade the multifractal complexity decreases. PACS numbers: 87.19.Hh, 05.40.-a, 89.75.Da, 87.80.Vtp. 6026 - 6029en-US©2001 American Physical SocietyScience & technologyPhysical sciencesPhysics, multidisciplinaryPhysicsHuman circadian pacemakerMultifractal formalismRate-variabilitySleepTimeFluctuationsWaveletsRhythmsNon-programmaticActivities of daily livingAdrenergic beta-antagonistsAdultAtropineFemaleFractalsHeartMaleParasympathetic nervous systemParasympatholyticsSympathetic nervous systemActivities of daily livingq-bioGeneral physicsArticle10.1103/PhysRevLett.86.602693117