Introduction. Red blood cells are among the first to respond to the impact of the load factor. Under the influence of the load at the initial stage,a change in hemoconcentration occurs due to release of erythrocytes into the bloodstream. And with further load operation, there will be increase in hemodilution and erythrocytosis (Khmeleva SN, 1998, Belchenko LA 2001, parapara AA 2005; Perier C., 1999, Deitrick RW, 2002, Minetti M., 2006). Hemodilution occur due to the decrease in the number of red blood cells in the plasma and increase in the total volume of plasma. The plasma flow from blood and organs.This result in redistribution of the total blood volume, hematocrit, and red cell content. According to works Merrill E., Wells R., 1961 and Snigger G., 1971, there is an increase in hematocrit about 25%, which leads to an increase in blood viscosity by 20%.