INTRODUCTION: The aim of this study was to investigate the impact of an ultra-marathon (UM) with a distance of 100 miles on heart rate (HR) and heart rate variability (HRV). METHODS: Altogether, 28 runners (25 men and 3 women) received a 24-hour long-term ECG one week before the UM (U1), immediately after (U2) and after a week of recovery (U3). The influence of age, body mass index (BMI), HR and HRV on the run time as well as recovery were investigated. RESULTS: A rise in the baseline heart rate accompanied by a significant drop in SDNN values ​​(the standard deviation of all normal RR intervals) was found. Except for the age of the runners, BMI, HF and HRV did not predict the competition time. Full return of HRV to the athlete’s individual baseline did not occur within one week. There were no significant differences between finishers and non-finishers in analyzed parameters. CONCLUSION: The present results show that a 100-mile run leads to an increase in sympathetic activity and thus to an increase in heart rate and a decrease in HRV. In addition, HRV seems to be a suitable parameter to evaluate full recovery after a 100-mile run.

BACKGROUND: The aim of this study was to investigate the impact of an ultra-marathon (UM) with a distance of 100 miles on heart rate (HR) and heart rate variability (HRV). METHODS: 28 runners (25 males and 3 females) underwent 24-hour Holter ECG monitoring one week before the UM (U1), immediately after (U2) the UM and after a week of recovery (U3). The influence of age, body mass index (BMI), HR and HRV on the run time as well as recovery were investigated. RESULTS: A rise in the baseline heart rate (18.98%) immediately after the run accompanied by a significant drop in the standard deviation of all normal RR intervals (SDNN) (7.12%) one week after. Except for the age of the runners, BMI, HR and HRV showed no influence on the competition time. Full return of HRV to the athletes´ individual baseline did not occur within one week. There were no significant differences between finishers and non-finishers in analysed parameters.CONCLUSION: The present results show that a 100-mile run leads to an increase in sympathetic activity and thus to an increase in heart rate and a decrease in HRV. In addition, HRV might be a suitable parameter to evaluate full recovery after a 100-mile run.

AimsThis study aimed to investigate the impact of an ultramarathon (UM) with a distance of 100 miles on heart rate (HR) and heart rate variability (HRV).Methods28 runners (25 men and 3 women) underwent 24-hour Holter ECG monitoring 1 week before the UM, immediately after the UM and after a week of recovery. The influence of age, body mass index (BMI), HR and HRV on the run time and recovery was investigated.ResultsA rise in the baseline HR (18.98%) immediately after the run accompanied by a significant drop in the SD of all normal RR intervals (7.12%) 1 week after. Except for the runners’ age, BMI, HR and HRV showed no influence on the competition time. Full return of HRV to the athletes’ baseline did not occur within 1 week. There were no significant differences between finishers and non-finishers in the analysed parameters.ConclusionThe present results show that a 100-mile run leads to an increase in sympathetic activity and thus to an increase in HR and a decrease in HRV. Also, HRV might be a suitable parameter to evaluate the state of recovery after a 100-mile run but does not help to quantify the status of recovery, as the damage to the tendomuscular system primarily characterises this after completing a UM.