Electrocardiographic Analysis of Runners Before, During, And After An Ultramarathon

Abstract

It is known that ultra-endurance exercise places extraordinary stress on the cardiovascular system. Still, limited data are available examining cardiac physiology throughout an ultramarathon. Additionally, such events have been implicated in augmented ectopic activity and sudden cardiac death. Therefore, detecting arrhythmias during an ultramarathon event would be of interest. PURPOSE: The purpose was to evaluate electrocardiographic activity continuously before, during, and after a mountainous ultramarathon run. METHODS: Twenty-seven runners who registered for either a 44 kilometer (5 men, age 49.2 ± 1.6y ; 4 women, age 43.8 ± 11.9y) or 163 km (14 men, age 40.1 ± 7.8y; 4 women, age 38.8 ± 11y) trail race underwent continuous EKG monitoring 1 day before an ultramarathon run (baseline), during, and a minimum of 24 hours postrace. Electrocardiograms were analyzed for the presence of arrhythmias. Participants completed a survey that included detailed health and running histories. RESULTS: There were no recognizable differences between men and women in HR or rhythms, so sexes were combined for group analyses. Ultramarathon experience ranged from 1 to 36y of racing with most racing 4-6y. No runners reported a history of coronary artery disease, and besides caffeine, no runners reported use of substances that would affect HR or rhythm. Minimum HR the night before the race was 42 ± 6 BPM and ranged from 31-53 BPM. Rare PVCs and/or PACs occurred in 17 of 18 runners, and throughout the observational period, clinically relevant arrhythmias were observed in 5 runners. Generally, occurrences of arrhythmias were no different during or after than before the race. CONCLUSIONS: In a small sample of endurance runners at one ultramarathon run, the prevalence of arrhythmias during and after an ultramarathon race was not different from baseline.