Introduction. The modification of physiological processes in the body lead to increase the risk of developing fragility during aging. According to previous studies, physical activity has a positive effect on the nevrological whole body’s control, such us the functional state of blood circulation during physical exercise as main direct of physical rehabilitation. Caused by low level of physical activity hypersympathicotonia lead to an increase in the reactivity of the sympathetic nervous system and the risks of advers outcomes for the middle and the elderly age group. The purpose of the study is to improve diagnostic procedures for assessing the impact of physical rehabilitation on changing the randomness of blood circulation indicators during the exercise test in middle-aged and elderly patients. Materials and methods. The study was conducted for two age groups (56±3.5 years and 68±1.8 years). Entropy (ApEn, SampEn) was used as the studied parameter. Blood circulation parameters were recorded using the «Cardiotechnika-SACR» (Inkart, St. Petersburg) during a bicycle physical test with low-intensity ramp protocol increasing of physical activity (from 40 to 60 watts). Results. The advantages of using nonlinear dynamics methods for the analysis heart rate variability (RR) and time intervals of blood pressure (STI, DTI) are for monitoring regulatory circulatory systems. Conclusion. It can be influence on the regulatory mechanisms of blood circulation during physical rehabilitation in the change of both cardiac activity and blood pressue, which can be traced during exercise tests. All parameters are allowed to obtain statistically significant differences before and after physical rehabilitation in middle-aged or elderly patients. After assessment of randoms we are allowed to confirm the influence of physical rehabilitation on the variability of blood circulation, accounts age-related characteristics, exept heart rate variability, also variable blood pressure (STI and DTI), which manifests condition of the body in various stress.