Purpose of the study: To assess the degree of adaptation of the cardiovascular system to increased physical activity in professional football players with heart rhythm disturbances. Material and methods: 138 players were observed, who performed for 6 professional football clubs of the major league, with the help of clinical, instrumental and functional methods of research of the cardiovascular system. Results: Analysis of the results of ECG showed that 24.6% of football players had a normal ECG. In 53.6% observed “benign arrhythmia” in the form of sinus bradycardia, slowing conduction along the right branch of the His bundle, sinus arrhythmia, pacemaker migration within the sinus node and 1st degree atrioventricular (AV) block.