According to the researchers, the permanent bone loss due to spaceflight is equivalent to about 10 years of age-related bone loss on Earth.
The Canadian Space Agency has discovered new research findings on space travel showing that permanent bone loss occurs in astronauts following long-duration space travel, raising questions about longer space travel being considered in the decades to come.
“We found that weight-bearing bones have only partially recovered in most astronauts one year after spaceflight,” said Dr. Leigh Gabel, assistant professor of kinesiology at the McCaig Institute at the University of Calgary for Bone and Joint Health from the Cumming School of Medicine.
This suggests that the permanent bone loss from spaceflight is roughly equivalent to 10 years of age-related bone loss on Earth, he added.
This loss occurs because bones that would normally bear weight on Earth, like your legs, don’t have to bear weight in space.
“Bone loss happens in humans – as we age, get injured, or in any scenario where we can’t move the body, we lose bone,” Gabel explained, via a statement from the university on June 30.
Researchers have followed 17 astronauts after spaceflight since 2015 and studied the supporting bones.
Some astronauts who flew shorter missions, less than six months, recovered lower body bone strength and density, compared to those who flew for longer durations. Astronauts are said to have had varying conditions when landing on Earth.
“Understanding what happens to astronauts and how they recover is incredibly rare. It allows us to look at the processes that take place in the body in such a short time. We would have to follow someone for decades on Earth to see the same amount of bone loss,” says Gabel.
Former university chancellor and Canadian astronaut Robert Thirsk explained the “weird” feeling of returning to Earth.
“Just as the body must adapt to spaceflight at the start of a mission, it must also readapt to Earth’s gravity field at the end,” Thirsk explains. “The fatigue, dizziness and imbalance were immediate challenges for me upon my return. Bones and muscles take the longest to recover after spaceflight. But one day after landing, I felt comfortable again as an Earthling.
As Thirsk puts it, “Astronauts will venture into deep space this decade, and in the centuries to come, humanity will populate other star systems. Now let’s push the boundaries of space exploration to make that vision possible.” .
The results are published in Scientific Reports, a peer-reviewed publication.