In general, exercise has an effect on both plasma and red blood cells. The effect on plasma is an increase in circulating blood volume due to mobilization of stored blood during exercise. The effect on erythrocytes is a temporary increase in erythrocytes during exercise, and the greater the amount of exercise, the greater the increase in erythrocytes during the same time of exercise. The number of red blood cells can return to normal after 1-2 hours of exercise cessation. The increase in erythrocytes during exercise may be related to the release of stored blood volume and plasma concentration. People who exercise for a long time have even lower than normal erythrocyte levels during quiet time, but higher than normal total erythrocyte counts, which is due to the excessive increase in their plasma volume. At the same time, the deformability of erythrocytes increases in chronically exercising people, and these changes both reduce the blood viscosity during quiet time, decrease the resistance to circulation, and reduce the load on the heart, and ensure a corresponding increase in hemoglobin content during muscle exercise.