The monograph is devoted to current problems of the functioning of the cardiovascular system in athletes. Based on data from domestic and foreign studies, the formation and essence of modern concepts of both the physiological and pathological sports heart are considered, the concepts of morphological, electrophysiological, regulatory, arrhythmogenic heart remodeling, and features of non-ischemic myocardial fibrosis in athletes are revealed. Considerable attention is paid to gender and age differences in the adaptation of the circulatory system to physical activity, and to the peculiarities of adaptation of athletes with cardiovascular pathology to the conditions of sports activity. International classifications of sports for the needs of sports cardiology are provided, incl. for 2018 and 2020 The latest foreign and domestic recommendations are analyzed in detail, as well as the current legislative documents of the Russian Federation regulating the admission to sports of persons with cardiovascular pathology. Separate sections of the book are devoted to arterial hypertension and myocarditis in athletes, incl. in the context of the Covid-19 pandemic, as well as diseases that are risk factors for sudden cardiac death in sports. The author's concept of stress-induced cardiomyopathy in athletes is presented. The book is addressed to sports medicine doctors, as well as pediatricians, cardiologists, functional diagnostics doctors, therapists, general practitioners, clinical residents, graduate students, and sports specialists.