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Destruction of newly released red blood cells in space flight


Medicine & Science in Sports & Exercise: October 1996 - Volume 28 - Issue 10 - p 42-44
International Workshop on Cardiovascular Rearch in Space: Body Fluid Metabolism and Control of Intravascular Volume

Space flight results in a rapid change in total blood volume, plasma volume, and red blood cell mass because the space to contain blood is decreased. The plasma volume and total blood volume decreases during the first hours in space and remain at a decreased level for the remainder of the flight. During the first several hours following return to earth, plasma volume and total blood volume increase to preflight levels. During the first few days in space recently produced red blood cells disappear from the blood resulting in a decrease in red blood cell mass of 10-15%. Red cells 12 d old or older survive normally and production of new cells continues at near preflight levels. After the first few days in space, the red cell mass is stable at the decreased level. Following return to earth the hemoglobin and red blood cell mass concentrations decrease reflecting the increase in plasma volume. The erythropoietin levels increase responding to “postflight anemia”; red cell production increases, and the red cell mass is restored to preflight levels after several weeks.

Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030; and Johnson Space Center, Houston, TX

Submitted for publication December 1995.

Accepted for publication May 1996.

Address for correspondence: Clarence P. Alfrey, Baylor College of Medicine, Baylor Plaza, Houston, TX 77030.

©1996The American College of Sports Medicine