A race against time: timing constraints of cardiac filling and athletic performance

Abstract

Cardiac filling is constrained by a reduced ejection time and diastolic period as heart rate increases during exercise. We compared cardiac filling dynamics in endurance athletes and controls during exercise to determine how athletic status influences hemodynamic constraints during exercise. Thirty-two participants (21 endurance athletes and 11 controls) underwent exercise echocardiography at 20, 40, and 60% of peak power output. We measured cardiac timing, stroke volume (SV), and flow rates (SV indexed to body surface area and phase duration). Data were analyzed using linear mixed models. Athletes demonstrated resting bradycardia (44 ± 8 vs. 68 ± 14 beats/min, P < 0.001), through an extende..