Effects of Simulated Weightlessness on 0rthostatic Endurance of Volunteers in Head-down Position -6° Bed Rest for 15 Days

Object: The effectiveness of simulated weightlessness on orthostatic endurance of healthy volunteers were observed by head-down-6° bed rest test.Method: The experiment was conducted in October 2020 at Space Science and Technology Institute (Shenzhen). A total of 9 volunteers were enrolled. Before -6° head-down bed rest and after getting up, HUT + LBNP (standing stress + lower body negative pressure) was performed on the volunteers. The time of standing stress and cardiac physiological function were observed, objective: to investigate the effect of simulated weightlessness on orthostatic endurance of volunteers.Result: After 15 days of -6° head-down bed-rest to simulate weightlessness, all volunteers' standing endurance time and cardiac physiological function indexes were worse than those before bed-rest during HUT + LBNP (P<0.05).Conclusion: -6° head-down bed rest for 15 days can reduce the volunteers standing endurance.