Exercise Within LBNP to Produce Artificial Gravity

Integrated physiologic countermeasures are needed to maintain orthostatic tolerance after spaceflight or bed rest. We hypothesized that supine exercise during LBNP would prevent bed rest-induced loss of orthostatic tolerance by preventing hemoconcentration. In a study conducted jointly with NASA Johnson Space Center and the University of Texas Medical Branch, Galveston, TX, fifteen male subjects underwent 5 days of 6 deg head-down bed rest: 5 control subjects did not exercise, and 10 performed 30 min/day of supine interval treadmill exercise at intensities up to 90% VO(sub 2peak). We will undertake two 14 day bed-rest studies (6 deg head-down tilt bed rest, HDT) to investigate the mechanism of action and efficacy of our partial vacuum exerciser concept. These 14 day bed rest studies were chosen to simulate current microgravity exposures for Space Shuttle crew members.