Researchers say astronauts lose bone mass in space that is not restored.
Previous studies have shown that astronautslose 1 to 2% of their bone density for every month they spend in space as the lack of gravity takes the strain off their legs. To find out how astronauts recover after returning to Earth, scientists scanned the wrists and ankles of 17 specialists before, during and after their stay on the International Space Station (ISS).
According to one of the authors of the study,the bone density lost by the astronauts was equivalent to what they would have lost in a few decades on Earth. The researchers found that nine astronauts' lower leg density did not fully recover after a year on Earth. Astronauts who participated in the longest missions - from four to seven months on the ISS - recovered the slowest.