How Long Does It Take to Rebuild Bone Lost During Space Flight?
Are bigger bones stronger bones? Not necessarily, according to a
recent NASA study that seeks to ensure healthy bones in
astronauts. A four-year study of the long-term effects of
microgravity on the bones of International Space Station crew
members showed that the astronauts, on average, lost roughly 11
percent of their total hip bone mass over the course of their
mission. Image at right: A Dual Energy X-ray Absorptiometry
(DEXA) scan of a human hip bone, left, and a human spine, right.
Credit: NASA The study also found that a year after each crew
member had returned to Earth, much of their lost bone mass was
replaced. However, the bone structure and density had not
returned to normal and signs of hip strength had not recovered
at one year, although it had increased slightly compared to
post-flight levels. Researchers say it could take much longer
than a year to regain the lost strength. The study's findings
are important because bone loss during