The study of astronauts reveals the effects of space travel on human bones

Will Dunham (Reuters)

Washington, United States ● Mon, July 4, 2022 7/4/2022 10:30 AM 0 76b99ae81be4b2e052851b8c96b1fe42 2 Science and technology astronaut, space travel, science, space exploration Free

A study of bone loss in 17 astronauts who flew aboard the International Space Station provides a more complete understanding of the effects of space travel on the human body and the steps that can mitigate it, crucial knowledge ahead of possible missions ambitious futures.

The research gathered new data on astronauts ’bone loss caused by space microgravity conditions and the degree to which bone mineral density can be recovered on Earth. It involved 14 men and three astronauts, with an average age of 47 years, whose missions ranged from four to seven months in space, with an average of about 5 and a half months.

One year after returning to Earth, astronauts showed, on average, a bone mineral density reduced by 2.1% in the tibia – one of the bones in the lower leg – and a reduction in bone strength by 1.3 %. Nou did not regain bone mineral density after space flight, experiencing permanent loss.

“We know that astronauts lose bone on long-haul space flights. What’s new in this study is that we followed the astronauts for a year after their space trip to understand if and how the bone recovers,” he said. University of Calgary professor Leigh Gabel, exercise scientist. who was the lead author of the research published this week in the journal Scientific Reports.

“Astronauts experienced significant bone loss during the six-month spaceflight, a loss we expect to see in older adults for two decades on Earth, and only recovered about half of that loss after a year back. on Earth, ”Gabel said.

Bone loss occurs because the bones that normally support weight on Earth do not carry weight in space. Space agencies will need to improve countermeasures – exercise and nutrition regimes – to help prevent bone loss, Gabel said.

“During space flight, the thin bone structures thin out and eventually some of the bone bars disconnect from each other. Once the astronaut returns to Earth, the remaining bone connections can thicken and strengthen, but those that disconnected in space cannot be rebuilt., so the astronaut’s overall bone structure changes permanently, “Gabel said.

The astronauts in the study have flown on the space station for the past seven years. The study did not give their nationalities, but they were from the US space agency NASA, the Canadian Space Agency, the European Space Agency and the Japan Aerospace Exploration Agency.

Space travel poses several challenges to the human body, key concerns for space agencies as they plan new explorations. For example, NASA aims to send astronauts back to the moon, a mission that is now scheduled for 2025 at the earliest. This could be a prelude to future astronaut missions to Mars or a long-term presence on the lunar surface.

“Microgravity affects many body systems, including muscles and bones,” Gabel said.

“The cardiovascular system also undergoes many changes. Without gravity pulling the blood to our feet, astronauts experience a change in fluid that causes more blood to build up in the upper body. This can affect the cardiovascular system and the vision.

“Radiation is also a major health concern for astronauts, as the more they move from Earth, the more exposure to solar radiation and the higher the risk of cancer,” Gabel said.

The study showed that longer space missions resulted in greater bone loss and a lower likelihood of recovery later. In-flight exercise – space station endurance training – was important in preventing muscle and bone loss. It was found that astronauts who carried more dead weight compared to what they usually did on Earth were more likely to recover the bone after the mission.

“There’s a lot we still don’t know about how microgravity affects human health, especially on space missions of more than six months, and about the long-term health consequences,” Gabel said. “We really hope that bone loss eventually gets aligned in longer missions, that people stop losing bones, but we don’t know that.”

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