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

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.

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.

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.

An extreme endurance exercise could induce temporary myocardial hypertrophy and contractility reduction.