Causes and consequences of reduced blood volume in space flight - A multi-discipline modeling study

A group of mathematical models of various physiological systems have been developed and applied to studying problems associated with adaptation to weightlessness. One biomedical issue which could be addressed by at least three of these models from varying perspectives was the reduction in blood volume that universally occurs in astronauts. Accordingly, models of fluid-electrolyte, erythropoiesis, and cardiovascular regulation were employed to study the causes and consequences of blood volume loss during space flight. This analysis confirms the notion that alterations of blood volume are central to an understanding of adaptation to prolonged space flight. More importantly, the modeling studies resulted in specific hypotheses accounting for plasma volume and red cell mass losses and testable predictions concerning the behavior of the circulatory system.