WISE‐2005: Lower Body Negative Pressure Treadmill and Resistive Exercise Countermeasures Maintain Physiologic Function in Women during 60‐days of Simulated Microgravity

We hypothesized that supine LBNP treadmill exercise combined with Flywheel resistive exercise maintains upright physiologic responses following 60‐days of head‐down tilt (HDT) bed rest (BR). METHODS: 16 healthy women (age 25–40 years) underwent 60‐days HDT (‐6°) BR. Women were assigned to either a non‐exercise control group (CON, n=8) or to an exercise group (EX, n=8). EX subjects performed a 40‐min, variable intensity LBNP exercise protocol at foot‐ward forces between 1.0–1.1 times body weight, followed by 10‐min of resting LBNP 3–4 days/week. Resistive exercise of maximal concentric and eccentric supine leg press and heel raise exercises were performed using a flywheel ergometer 2–3 days/week. IRBs approved this study with informed/written consent. RESULTS: Post‐BR VO 2 pk was not different in EX (−3.3±1.2%) but decreased significantly in CON (−21.2±2.1%), p< 0.05. Post‐BR orthostatic tolerance time (mean±se) decreased significantly less in EX (19.3±1.3 to 14.4±1.5 min) than in CON (17.5±0.1 to 9.1±1.5 min), p=0.03. Post‐BR muscle strength decreased significantly in CON, but was preserved in EX. Post‐BR bone resorption was greater than pre‐BR in both groups (p<0.05). Bone formation markers, were significantly elevated (p<0.05) in EX than in CON. CONCLUSIONS: Supine LBNP treadmill exercise along with flywheel resistive exercise maintains upright exercise capacity, orthostatic responses and muscle strength during 60‐days HDT BR. Supported by ESA, CSA, CNES; and NASA: NNJ04HF71G and NNJ04HF72G.