NASA initiated a project to begin systematically exploring the utility of AG as a multi-system countermeasure in ground-based venues using test subjects deconditioned by bed rest. The goal of this project was to explore the efficacy of AG as a multi-system countermeasure to form a basis for future flight investigations that defined prescriptions for applying AG during long-duration space flight.
The project scope was performance of a pilot study according to an established standardized protocol. The goals of the project was to :
This study was performed in conjunction with the NASA Bed Rest Project, which has defined a multi-phased approach for implementing NASA-funded bed rest studies. It was implemented at the General Clinical Research Center (GCRC) located at The University of Texas Medical Branch (UTMB) in Galveston, Texas. It was the first study to utilize the GCRCs new short-radius centrifuge facility. The study followed the NASA Bed Rest Project guidelines for subject recruitment, standard conditions of bed rest, and standard measures collection with modifications to achieve the research protocol objectives. Bed Rest Standard Measures, which represent a series of medical and research assessments to evaluate the human responses to bed rest under standardized bed rest conditions, were used to the extent possible to provide dependent measures to test the study hypotheses, but were modified and supplemented as described below to meet the peer-reviewed scientific objectives of the protocol.
Subjects were recruited and screened, and if approved, placed in a bed rest facility for testing and data collection during 11 days of ambulatory acclimation, 21 days of 6° head down tilt bed rest, and 9 days of ambulatory recovery. Subjects were randomly assigned to either the treatment group or control group. Subjects assigned to the treatment group received daily one hour spins on the short radius centrifuge. The extents to which the bone, muscle, cardiovascular, and neural loading provided by these spins overcome the deconditioning associated with bed rest were tested. Subjects assigned to the control group were transported to the centrifuge each day and participated in all centrifuge monitoring procedures, but did not participate in the centrifuge runs.