Analysis of head-down tilt as an analog of weightlessness using a methematical simulation model

Leonard, J. I.

Antiorthostasis or head down tilt of a moderate degree was used as a ground based analog of weightless space flight to study headward fluid shifts, decreased plasma volume, orthostatic intolerance and muscular skeletal degradation. A mathematical model was used to help interpret these observations. The model proved most valuable for these studies was originally developed as a description of the major circulatory, fluid and electrolyte control systems. Two different experimental studies are employed to validate the model. The first is a 24 hour head down tilt study and the second is a 7 day head down bed rest study. The major issues addressed include the reduction in plasma volume, the dynamic changes of venous pressure and cardiac output, the extent of central hypervolemia during long term zero g exposure, the existence of an early diuresis, the mechanisms which alter the renal regulating hormones during the short term and long term periods, the significance of potassium loss on other zero g responses, and the role of transcapillary filtration in adjusting fluid shifts. The use of mathematical models as an interpretive and analysis technique for experimental research for space life science is illustrated.

Document ID

19850017807

Acquisition Source

Legacy CDMS

Document Type

Contractor Report (CR)

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Date Acquired

September 5, 2013

Publication Date

September 4, 1984

Subject Category

Report/Patent Number

Accession Number

85N26118

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Public

Work of the US Gov. Public Use Permitted.

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