Dr. Peter Cavanagh and his colleagues are conducting a bed-rest study to better understand the amount of exercise loading that is necessary to reduce bone loss in astronauts during long-duration spaceflight. Volunteers in a 12-week head-down bed-rest study were randomly assigned into one of two groups, an exercise and a non-exercise group. The exercise group participated in an individualized exercise program each day using a vertical treadmill with a one g applied subject load that provided a flight-like simulation of the treadmill exercise that is performed in space. The goal of the exercise prescription is to replace the daily load stimulus in one g which was measured during entire days of free living prior to bed rest. In order to compare the changes between the exercise and non-exercise group members, measurements of bone mineral density, muscle volume and strength are taken at the beginning and the end of the 12-week period. Bone metabolic markers are also collected.
In addition to providing an answer if exercise can adequately protect the body from bone and muscle loss during spaceflight, the data will be helpful to understand the importance of exercise for prevention and treatment of bone diseases such as osteoporosis.