The scientific work is devoted to the development of the structural and mathematical model of the heart reaction to the load and experimental study of the perception of the test load and recovery of the initial state by trained and untrained students with a further analysis of their mental working capacity. It is determined that the use of a functional test allows you to analyze the physical abilities of a person. It has been shown that even for trained people, stress can cause a stressful reaction in which the recovery time increases. For untrained people is characterized by a decline in efficiency.