Effect of Training Load on Post-Exercise Cardiac Biomarkers in Healthy Children and Adolescents: A Systematic Review of the Existing Literature

Background: Postexercise release of cardiac biomarkers (cardiac troponins, cTn, and N-terminal pro b-type natriuretic peptide, NT-proBNP) is a well-known phenomenon in adults, although it remains unclear how it manifests in children. The aim of this review is to compare the pre-exercise with the post-exercise measurement of serum cardiac biomarkers, as well as to analyze their post-exercise release based on age, sex, and exercise intensity and duration. Methods: The terms troponin, football, swimmers, marathon, run, and exercise were used in a literature search at National Library of Medicine. The search was further refined by adding the keywords athletes, children, adolescents, and sport. Results: Fifteen pediatric studies and four studies with a mixed population of adults and children totaled 19 studies for the final analysis. In addition to them, some adult studies have been included for comparison. The kinetics of the cTn and NT-proBNP response after exercise have been the subject of our interest. While the impact of sport type, age, and sex has not yet been fully characterized, the existing data points to considerable impacts of sport intensity and duration on post-exercise biomarkers elevation. Most of the findings came from endurance sports, but the evidence is sparse. Furthermore, there is only limited data on women and less on young adults, African Caribbeans, and professional athletes. Conclusions: Both amateur and competitive athletes can exhibit post-exercise release of both cTn and NT-proBNP. This is transient and lacks pathological significance, in contrast with adult population, in which exercise-induced increases in in these biomarker levels may not always be benign. While NT-proBNP release is still primarily driven by activity duration, cTnT release is additionally affected by exercise intensity. To define individual ranges of normality for postexercise cTn and NT-proBNP elevation, the role of several confounders (age, sex, sport type/intensity etc.) remains to be further elucidated.