The circulatory system is made up of the heart, veins, arteries, and capillaries. The main function of the heart is to create the force by which blood flows through the body. Its work can be divided into two periods: systole and diastole. During diastole, the heart fills with blood and during systole, there is a contraction of the heart muscle which directs that blood into the blood vessels. In order to maintain normal heart function and to prevent the occurrence of cardiovascular diseases, it is necessary to exercise. Activation of skeletal muscles through exercise causes a number of changes in the circulatory system. Those changes can be divided functionally into acute, i.e. those that occur immediately after exercising or even during exercise, and adaptive. Adaptive changes occur after a longer period of exercising. The changes are mostly reflected in blood pressure values, cardiac output, and heart rate. To sum up, the circulatory system, its function and mechanisms of functioning, adaptation to the load caused by exercise, i.e. physical exertion will be described in this final paper.