Astronauts lose decades worth bone in space

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Astronauts lose decades worth bone in space

Astronauts lose decades worth of bone mass in space that many people don't recover even after a year ago, researchers have found, warning that it could be a big concern for future missions to Mars.

Previous research shows that astronauts lose between 1% and 2% of their bone density for every month spent in space, as lack of gravity takes pressure off their legs when it comes to standing and walking.

A new study looked at the wrists and ankles of 17 astronauts before, during and after a stay on the International Space Station ISS The bone density lost by astronauts was equivalent to how much they would shed if they were back on Earth, said Steven Boyd, of Canada's University of Calgary and director of McCaig Institute for Bone and Joint Health.

The researchers found that the shinbone density of nine of the astronauts had not fully recovered after a year on Earth and they were still lacking about a decade s worth of bone mass.

The astronauts who went on the longest missions, which ranged from four to seven months on the ISS, were the slowest to recover. The longer you spend in space, the more bone you lose, Boyd said.

Boyd said that it was a concern for future missions to Mars, which could see astronauts spend years in space.

Will it get worse over time? He said we don't know.

It is possible that we're in a steady state after a while, or it's possible that we're losing bone. I can't imagine that we d continue to lose it until there is nothing left. Over a three-year spaceflight to Mars, 33% of astronauts would be at risk of osteoporosis, according to a 2020 modelling study.

Boyd said that some answers could come from research currently being carried out on astronauts who spent at least a year onboard the ISS.

The head of medicine research at France's CNES space agency said that the weightlessness experienced in space is the most drastic physical inactivity there is. "With two hours of sport a day, it is like you are bedridden for the other 22 hours," said the doctor, who was not part of the study. It will not be easy for the crew to set foot on Martian soil when they arrive. It is very disabling. The study, which was published in Scientific Reports, shows how spaceflight affects the structure of bones.

Boyd said that if you thought of a body's bones like the Eiffel Tower, it would be as if some of the connecting metal rods that hold the structure up were lost. When we return to Earth, we thicken what remains, but we don't actually create new rods, he said.

Some exercises are better at retaining bone mass than others, according to the study. Deadlifting proved to be more effective than running or cycling, suggesting more heavy lower-body exercises in the future.

The astronauts who were mostly fit and in their 40 s did not notice the drastic bone loss, Boyd said. Canadian astronaut Robert Thirsk, who has spent most of his time in space, said that for him, his bones and muscles took the longest to recover after spaceflight.

But within a day of landing I felt comfortable as an earthling," he said in a statement accompanying the research.