Author(s): DANIELSSON, T., CARLSSON, J., AHNESJO, J., BERGMAN, P., Institution: LINNAEUS UNIVERSITY, Country: SWEDEN, Abstract-ID: 334

INTRODUCTION:
INTRODUCTION:
While overall physical activity is clearly associated with better short-term and long-term health, It is well known that ultra-endurance races causes damage to skeletal and cardiac muscles. However, it still remains unclear whether these effects after exercise is a marker of occult disease, e.g., represents cardiac damage, or is harmless. Two competing hypotheses suggest that either (A) the biomarker response is a transient harmless and normal phenomenon, or (B) that repeated ultra-endurance races may in the long-term cause negative health consequences, such as atrial fibrillation. If hypothesis (B) is true, then it would be important to know whether individuals who are at a particular risk of developing such health consequences can be identified. To that end it is important to understand the individual response to ultra-endurance events.

METHODS:
Thirteen individuals (7 females) who participated in two Ironman races and had been included in the Iron(WO)man study were investigated. Blood samples were analyzed for cardiac troponin T, N-terminal of the prohormone brain natriuretic peptide (NT-proBNP), myoglobin, creatine kinase (CK) and serum creatinine. Stability of the biomarker response between the two occasions was estimated by calculating tracking coefficients using Spearman correlation.

RESULTS:
There were no intra individual differences in the post-race values in any of the studied biomarkers (all p>0.05). Overall, substantial tracking coefficients (rho=0.60-0.77) were identified as a sign of stability in the response, i.e., the presence of high and low responders.
CONCLUSION:
Based on the results of this study it appears that there are individuals who are at particular risk of getting high levels of biomarkers signaling cardiac and skeletal muscle damage. Future studies should be designed to answer the question whether there are unique responses in cardiac biomarker releases after exercise and whether they imply cardiovascular events in the future.