[Medical results from STS 1-4: analysis of body fluids]

Venous blood was drawn from the eight crewmembers of Space Shuttle flights STS-1 through STS-4 three times before lift-off and twice after landing, and the characteristics of biomedical blood components were evaluated. Twenty-four-hour urine pools were collected 30 days before flight and on landing day or day 4 after landing, and electrolytes, selected hormones and other components were measured. The results indicated that although fluid and electrolyte losses occur during space flight, conservation of these substances is begun almost immediately upon cessation of weightlessness. Enzyme and hormone measurements indicated that landing may have caused some stress on crewmembers.