title: Sleep-dependent changes in the coupling between heart period and blood pressure in human subjects.
abstract: We investigated whether in human subjects, the pattern of coupling between the spontaneous fluctuations of heart period (HP) and those of systolic blood pressure (SBP) differs among wake-sleep states. Polysomnographic recordings and finger blood pressure measurements were performed for 48 h in 15 nonobese adults without sleep-disordered breathing. The cross-correlation function (CCF) between the fluctuations of HP and SBP at frequencies <0.15 Hz was computed during quiet wakefulness (QW), light (stages 1 and 2) and deep (stages 3 and 4) nonrapid-eye-movement sleep (NREMS), and rapid-eye-movement sleep (REMS). A positive correlation between HP and the previous SBP values, which is the expected result of baroreflex feedback control, was observed in the sleep states but not in QW. In deep NREMS, the maximum CCF value was significantly higher than in any other state, suggesting the greatest baroreflex contribution to the coupling between HP and SBP. A negative correlation between HP and the subsequent SBP values was also observed in each state, consistent with the mechanical feed-forward action of HP on SBP and with central autonomic commands. The contribution of these mechanisms to the coupling between HP and SBP, estimated from the minimum CCF value, was significantly lower in deep NREMS than either in light NREMS or QW. These results indicate that the pattern of coupling between HP and SBP at low frequencies differs among wake-sleep states in human subjects, with deep NREMS entailing the highest feedback contribution of the baroreflex and a low effectiveness of feed-forward mechanisms.
authors.affiliation: Dipartimento di Fisiologia Umana e Generale, Università di Bologna, Bologna, Italy. alessandro.silvani3@unibo.it
authors.forename: Alessandro
authors.initials: A
authors.lastname: Silvani
authors.forename: Daniela
authors.initials: D
authors.lastname: Grimaldi
authors.forename: Stefano
authors.initials: S
authors.lastname: Vandi
authors.forename: Giorgio
authors.initials: G
authors.lastname: Barletta
authors.forename: Roberto
authors.initials: R
authors.lastname: Vetrugno
authors.forename: Federica
authors.initials: F
authors.lastname: Provini
authors.forename: Giulia
authors.initials: G
authors.lastname: Pierangeli
authors.forename: Chiara
authors.initials: C
authors.lastname: Berteotti
authors.forename: Pasquale
authors.initials: P
authors.lastname: Montagna
authors.forename: Giovanna
authors.initials: G
authors.lastname: Zoccoli
authors.forename: Pietro
authors.initials: P
authors.lastname: Cortelli
mesh_terms: D000328:Adult; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology*; D003627:Data Interpretation, Statistical; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012890:Sleep / Q000502:physiology*; D012891:Sleep Apnea Syndromes / Q000503:physiopathology; D012894:Sleep Stages / Q000502:physiology; D012895:Sleep, REM / Q000502:physiology