Indeed, previous studies have shown an increase in biomarkers of cardiac damage (i.e. cardiac troponin I (cTnI), and N-terminal proB-type natriuretic peptide (Pro-BNP)) above upper reference limits (URL), which are still elevated 24–72 h after prolonged endurance exercise, without clinical symptoms of cardiac disease (Rubio-Arias et al. 2021; Traiperm et al. 2021). This evidence concerns the gene TNNI3 and heart disorder.