PURPOSE: There are few data examining cardiovascular physiology throughout a marathon. This study was devised to characterize electrocardiographic activity continuously throughout a marathon. METHODS: Cardiac activity was recorded from 19 subjects wearing a Holter monitor during a marathon. The 19 subjects (14 men and 5 women) were aged 39 ± 16 years (mean ± SD) and completed a marathon in 4:32:16 ± 1:23:35. Heart rate (HR), heart rate variability (HRV), T-wave amplitude, T-wave amplitude variability, and T-wave alternans (TWA) were evaluated continuously throughout the marathon. RESULTS: Averaged across all subjects, HRV, T-wave amplitude variability, and TWA increased throughout the marathon. Increased variability in T-wave amplitude occurred in 86 % of subjects, characterized by complex oscillatory patterns and TWA. Three min after the marathon, HR was elevated and HRV was suppressed relative to the pre-marathon state. CONCLUSION: HRV and T-wave amplitude variability, especially in the form of TWA, increase throughout a marathon. Increasing TWA as a marathon progresses likely represents a physiologic process as no arrhythmias or cardiac events were observed.
PURPOSE: There are few data examining cardiovascular physiology throughout a marathon. This study was devised to characterize electrocardiographic activity continuously throughout a marathon. METHODS: Cardiac activity was recorded from 19 subjects wearing a Holter monitor during a marathon. The 19 subjects (14 men and 5 women) were aged 39 ± 16 years (mean ± SD) and completed a marathon in 4:32:16 ± 1:23:35. Heart rate (HR), heart rate variability (HRV), T-wave amplitude, T-wave amplitude variability, and T-wave alternans (TWA) were evaluated continuously throughout the marathon. RESULTS: Averaged across all subjects, HRV, T-wave amplitude variability, and TWA increased throughout the marathon. Increased variability in T-wave amplitude occurred in 86 % of subjects, characterized by complex oscillatory patterns and TWA. Three min after the marathon, HR was elevated and HRV was suppressed relative to the pre-marathon state. CONCLUSION: HRV and T-wave amplitude variability, especially in the form of TWA, increase throughout a marathon. Increasing TWA as a marathon progresses likely represents a physiologic process as no arrhythmias or cardiac events were observed.
Authors: Juliane Herm; Agnieszka Töpper; Alexander Wutzler; Claudia Kunze; Matthias Krüll; Lars Brechtel; Jürgen Lock; Jochen B Fiebach; Peter U Heuschmann; Wilhelm Haverkamp; Matthias Endres; Gerhard Jan Jungehulsing; Karl Georg Haeusler Journal: BMJ Open Date: 2017-08-03 Impact factor: 2.692