While President George W. Bush waxes enthusiastically about astronauts further exploring space, the reality is that a major obstacle to an astronaut's health remains: bone loss in zero gravity.
Despite an exercise program designed to counter bone loss, astronauts on the International Space Station showed as much degradation as did their counterparts one decade ago on the Soviet space station
The primarily male study group lost a monthly average of about 1% of their exterior hipbone, about 2.5% of the interior or trabecular hipbone, and about 1% of the spine. Researchers used CT scans, the first time this method was used to assess bone loss in the hip and spine.
The astronauts' exercise regimen...