Electrocardiography is one of the leading and most common methods of instrumental research of heart biorhythms in primary medical and social care. The development of information and digital technologies, robotics for the purpose of preclinical assessment and ranking of myocardial status in different categories of the population for preventive purposes has allowed us to create highly sensitive methods for recording and processing biosignals. Converting and displaying a cardiosignal on the phase plane to obtain a averaged phase cardiocycle (APC) is a demostrative instrumental method of research. Aim of study — to determine the possibility of measuring the myocardial biosignal using the averaged cardiocycle of a single-channel ECG in the phase space. Materials and methods. Registration and analysis of the averaged biosignal obtained by converting a single-channel ECG in phase space, taking into account age and gender characteristics, was carried out using the FAZAGRAF software and hardware complex, which implements the original information technology for processing an electrocardiogram in phase space using computer graphics ideas and automatic pattern recognition methods. The parameters of the phase averaged cycle were subject to an analytical assessment: duration and amplitude characteristics of the P, Q, R, S, T waves (ms). The construction of a nonlinear mathematical model is carried out using an algebraic model of constructive logic based on predicate logic, followed by a multivariate assessment of the influence of each factor. The massive of verified data is represented by 58 016 values of indicators of the cardiovascular system in 1568 study participants aged 20 to 65 years. All subjects were divided into 2 groups: group 1 — 1087 conditionally healthy patients, group 2 — 471 patients with a verified diagnosis of pathology of the cardiovascular system. The information content of the QTc indicator was determined using ROC analysis. The age-related features of some parameters of the averaged phase cycle were examined in a cohort of 218 conditionally healthy schoolchildren aged 6—17 in Simferopol. The study of the adaptive features of the circulatory system was carried out in 40 sportsmen aged 14—15 with different profile orientation of training activity, which was divided into 2 cohorts. The first cohort included 20 wrestlers, the second — amounted to 20 football players. The gender characteristics of the reaction to natural aroma effects were studied in 30 conditionally healthy young people aged 17—18 (15 boys and 15 girls). Results and conclusion. The most significant parameters of the averaged phase cardiocycle for assessing the states and characteristics of their values were revealed. The obtained parameters of the averaged phase cardiocycle with a quantitative assessment of ranges with a significant number of subjects were used to solve preventive (predictive) problems of rehabilitation and sports medicine.