Volunteers will be randomly assigned to either a control or exercise group and will remain in bed for about 15 to 30 days, with the total period not exceeding 60 days.
Participants must stay in either a six-degree head-down or head-up bed position while eating, sleeping and undergoing medical tests. Those in the exercise group will also complete scheduled daily workouts.
Researchers use the head-down position to mimic the redistribution of body fluids and reduced muscle activity experienced by cosmonauts in space.
The study aims to examine effects on cardiovascular function, bone density and muscle loss, and to test countermeasures for long-term missions.