Changes of Cardiac Biomarkers in Ultramarathon Runners

Abstract

Introduction: The aim of this study is to examine and evaluate the effects of long-term stress on muscle and heart biomarkers after completing a 100 km ultramarathon. Material and Methods: Venous blood samples of nine runners (average age 38.8±10.2 years), who successfully finished a 100 km ultramarathon at an elevation of 3130 m, were examined before the start, at the finish line immediately after the run, one day after the run and then after 5 and 10 days. Clinical, laboratory, and somatometric data were obtained from all measurements, and biomarkers: aspartate aminotransferase (AST), cortisol (COR), troponin T (cTnT), creatine kinase (CK) and C-reactive protein (CRP). Also, their training experience and ultramarathon experience was monitored. Discovered values were further analyzed with the use of t-test a ω2 (ω2≥0.1), and Spearman’s rank correlation coefficient (r) at the significance level of p<0.05. Results: The average finish time of the runners was 13:55:40 (min: 12:12:35, max: 16:52:02). After finishing the ultramarathon, runners showed an average weight loss of 2.4 kg (p<0.05). The results show that hematological changes were caused by physiological stress and long-term physical load. The values of all monitored biomarkers showed a significant exceeding of the normal values immediately after the race in 8 competitors out of 9. The values of cTnT showed an increase of more than 50 % (pre-race: 8.2±2.3, post-race: 34.22±25.9 ng/l, max=98 ng/l). After 24 hours, however, this condition had returned to the normal values for all participants. The results show that the AST hepatic enzymes significantly correlated with the training experience (r=-0.41, p=0.043), the total number of kilometers run per year (r=-0.45, p=0.04) and the achieved finish time (r=0.67, p=0.001). At the same time, athletes who had the best finish time achieved lower CRP values (r=0.74, p=0.023) and cTnT values (r=0.49, p=0.040). The study found that the competitors who had the longest experience with ultramaraton had the lowest cTnT (r=0.44, p=0.050). Conclusion: Long-term physical stress is associated with metabolic and cardiovascular changes. Blood abnormalities found in our study suggest that due to long-lasting extreme stress, heart exhaustion may occur. However, these changes did not last long and after a few days they returned to the normal values for all runners.