SUMMARY
There is insufficient number of researches dedicated to cardiorespiratory adaptation in various physical activities in general, and especially in children and adolescents for certain types of sport.The objective: to determine the cardiorespiratory adaptation features in boys of primary school age engaged in football.Material and method. The study involved data from 92 male children aged 10-11 years, of which 68 children attended sports football schools. The study design included a general clinical examination, a spirometry, condition of cardiovascular system assessed with echocardiography, exercise stress test with cycle ergometer (VEM), 24-hours electrocardiogram (Holter - ECG) monitoring, and ambulatory blood pressure monitoring (ABPM).Results. Boys 10-11 years of age who play sports have increased values of minute respiratory volume and heart morphology indices, which reflect the myocardial hypertrophy development, although they correspond to normal Z-score values. The frequency of subjective complaints in boys who do not practice football is significantly more frequent when performing the exercise test. According to VEM, Holter-ECG and ABPM results in 57 (83.8%) of 68 football players (p=0.00393) changes were registered.Conclusions. We obtained statistically significant quantitative differences in the functional state of the cardiovascular system in children-athletes. Satisfactory cardiorespiratory adaptation of boys-athletes is documented during various stages of physical activity with the help of VEM and Holter-ECG and ABPM. The changes found in young athletes may result to further supervision of a pediatric cardiologist, but decision should made individually.