STATUS AND EFFICACY OF COUNTERMEASURES TO PHYSIOLOGICAL DECONDITIONING FROM SPACE-FLIGHT

The recent biomedical investigations conducted on the Space Shuttle an d Spacelab have provided a wealth of biomedical information, including the ability to test the efficacy of proposed countermeasures. This ac hievement was made possible by the ability to conduct mechanistic and control-interventive studies simultaneously with a large number of ind ividuals over a relatively brief period, and to compare these data wit h results obtained from the Skylab missions. Comparisons between short - and long-duration results were limited to establishing trends or ext rapolating from short-duration missions. To date, we have evaluated se veral protocols involving the lower-body negative pressure (LBNP) devi ce, the bicycle-ergometer, the treadmill and preparations for body-flu id replenishment. In many instances, the traditional means of applying these protocols were not sufficient to protect against space-related deconditioning. This paper will review current countermeasures and com pare their efficacy to that of existing protocols. Results from in-fli ght and ground-based experiments will be presented to illuminate the r ecommended protocols and procedures.