Six volunteers were selected and submitted at regular intervals throughout a 46-day control experiment in a climatic chamber to a large number of biological investigations (respiratory function, acid-base balance, circulatory function, biochemical determinations on blood and urine specimens) as well as psychomotor tests.
The results obtained clearly indicate that two kinds of adaptation occur:
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the first occurring during the first 2-3 days of confinement essentially marked by a significant increase of urinary volume and electrolyte output;
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the second, throughout the experiment mainly consists of a slight and progressive decrease of red blood cell count and plasma potassium.
Other parameter changes were well within range of the measuring technique's accuracy and physiological background; except for urinary calcium output which still remained elevated.
Finally, confinement failed to induce any significant degradation in psychomotor performances in spite of a sensation of fatigue.
Such a control experiment provides precise determination of the role played by confinement alone in the observed biological variations during submarine and space missions.