Exercise-training protocols for astronauts in microgravity

Based on physical working requirements for astronauts during intra- and extravehicular activity and on the findings from bed-rest studies that utilized exercise training as a countermeasure for the reduction of aerobic power, deterioration of muscular strength and endurance, decrements in mood and cognitive performance, and possibly for bone loss, two exercise protocols are proposed. One assumes that, during microgravity, astronaut exercise physiological functions should be maintained at 100 percent of ground-based levels. The other assumes that maximal aerobic power in flight can be reduced by 10 percent of the ground-based level.