The state of erythrocytes fully reflects the level of functional capabilities of the body and can be considered a reliable marker of its general condition. The study was carried out on 32 healthy young men who had low stable physical activity for a long time and started swimming training in the pool 3 times during the week. The control group consisted of 38 healthy young men who, over the past 5 years, regularly went in for swimming 3 times a week. Standard hematological and statistical methods for performing scientific research were applied. After six months of swimming training in the blood of beginner swimmers, a normalization of the number of metabolites of arachidonic acid, a reduction in the composition of erythrocytes of cholesterol molecules and lipid peroxidation products, and an increase in the content of phospholipids in them was noted. In the blood of beginner swimmers, there was an increase in the number of erythrocytes with a normal shape, and a significant decrease in the number of erythrocytes with a changed shape was achieved. For the boys of the control group, who had been swimming for a long time, it turned out to be characterized by a high content of unchanged erythrocytes in the blood and the optimum of their biochemical parameters. It can be assumed that regular swimming lessons already after six months provide significant positive dynamics of the surface properties of erythrocytes in the blood, which significantly improves the implementation of microcirculation and intensifies metabolism throughout the body.