title: Predominance of Intrinsic Mechanism of Resting Heart Rate Control and Preserved Baroreflex Sensitivity in Professional Cyclists after Competitive Training.
abstract: Different season trainings may influence autonomic and non-autonomic cardiac control of heart rate and provokes specific adaptations on heart's structure in athletes. We investigated the influence of transition training (TT) and competitive training (CT) on resting heart rate, its mechanisms of control, spontaneous baroreflex sensitivity (BRS) and relationships between heart rate mechanisms and cardiac structure in professional cyclists (N = 10). Heart rate (ECG) and arterial blood pressure (Pulse Tonometry) were recorded continuously. Autonomic blockade was performed (atropine-0.04 mg.kg-1; esmolol-500 μg.kg-1 = 0.5 mg). Vagal effect, intrinsic heart rate, parasympathetic (n) and sympathetic (m) modulations, autonomic influence, autonomic balance and BRS were calculated. Plasma norepinephrine (high-pressure liquid chromatography) and cardiac structure (echocardiography) were evaluated. Resting heart rate was similar in TT and CT. However, vagal effect, intrinsic heart rate, autonomic influence and parasympathetic modulation (higher n value) decreased in CT (P≤0.05). Sympathetic modulation was similar in both trainings. The autonomic balance increased in CT but still showed parasympathetic predominance. Cardiac diameter, septum and posterior wall thickness and left ventricular mass also increased in CT (P<0.05) as well as diastolic function. We observed an inverse correlation between left ventricular diastolic diameter, septum and posterior wall thickness and left ventricular mass with intrinsic heart rate. Blood pressure and BRS were similar in both trainings. Intrinsic heart rate mechanism is predominant over vagal effect during CT, despite similar resting heart rate. Preserved blood pressure levels and BRS during CT are probably due to similar sympathetic modulation in both trainings.
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), Medical School of University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Luciene Ferreira
authors.initials: LF
authors.lastname: Azevedo
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), Medical School of University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Patricia
authors.initials: P
authors.lastname: Perlingeiro
authors.affiliation: Clinical Arrhythmia Unit, Heart Institute (InCor), Medical School of University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Denise Tessariol
authors.initials: DT
authors.lastname: Hachul
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), Medical School of University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Igor Lucas
authors.initials: IL
authors.lastname: Gomes-Santos
authors.affiliation: Echocardiography Unit, Heart Institute (InCor), Medical School of University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Jeane Mike
authors.initials: JM
authors.lastname: Tsutsui
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), Medical School of University of Sao Paulo, Sao Paulo, Brazil.|Biodynamic of the Movement of the Human Body, School of Physical Education and Sport, University of Sao Paulo, Sao Paulo, Brazil.
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Negrao
authors.affiliation: Cardiovascular Rehabilitation and Exercise Physiology Unit, Heart Institute (InCor), Medical School of University of Sao Paulo, Sao Paulo, Brazil.|Rehabilitation Center, Hospital Israelita Albert Einstein, Sao Paulo, Brazil.
authors.forename: Luciana D N J
authors.initials: LD
authors.lastname: De Matos
mesh_terms: D000328:Adult; D056352:Athletes; D017704:Baroreflex / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D004562:Electrocardiography; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D012146:Rest
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