Effects of Super-ultramarathon Running on Cardiac Structure and Function in Middle-aged Men

BACKGROUND: It remains unclear whether high-intensity exercises result in deformities and reduced function of cardiac muscle. This study hypothesized that participants in a six-day super-ultramarathon (622 km) with sleep deprivation would show serial changes in cardiac structure and function pre- and post-marathon and during the recovery period. METHODS: Cardiac structure and function of middle-aged male volunteers were assessed through echocardiography at pre- and post-marathon, and at 2 recovery periods with a three-day interval. RESULTS: There were no differences in left ventricular end-diastolic and end-systolic dimensions, and end-diastolic volume between pre- and post-marathon. Interventricular septum thickness, left ventricular posterior wall thickness, left ventricular mass, and mass index significantly increased at post-marathon compared to pre-marathon, which decreased during the recovery period. Stroke volume and left ventricular ejection fraction significantly decreased at post-marathon, while both values increased during the recovery period. There were no significant differences in indices for left ventricular relaxation at each assessment period. CONCLUSIONS: An extreme endurance exercise could induce temporary myocardial hypertrophy and contractility reduction.