The research showed that astronauts suffered “significant” bone loss during six-month spaceflights – the equivalent of about two decades on Earth. Only about half of the bone loss was recovered a year after return – raising concerns for future missions to Mars and the Moon. Longer space missions resulted in increased bone loss and decreased chance of recovery. Bone loss occurs due to the weightlessness of space, where normally weight-bearing bones on Earth are weightless. The study was conducted on 17 astronauts – 14 men and three women with an average age of 47 – who flew on the International Space Station (ISS) over the past seven years. The crew came from the US space agency NASA, the Canadian and European Space Agency and the Japanese Aerospace Exploration Agency.
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They worked with a research team led by University of Calgary professor Leigh Gabel for a year after returning to Earth. Nine crew members experienced permanent bone loss after four to seven months on space missions. “Astronauts experienced significant bone loss during six-month spaceflights—loss that we would expect to see in older adults over two decades on Earth, and recovered only about half of that loss after a year back on Earth,” said Professor Gabel. research, published in the journal Scientific Reports. Image: The study has raised concerns about future trips to Mars. Photo: CNSA/REUTERS “We know that astronauts lose bone on long-duration spaceflights. “What’s innovative about this study is that we followed the astronauts for a year after their spaceflight to understand if and how the bones recover.” Space agencies need to improve countermeasures, such as exercise and diet, in an effort to prevent bone loss, Professor Gabel warned. In-flight exercise, including resistance training on the ISS, proved critical in preventing bone and muscle loss, the study found. Astronauts who completed more deadlifts compared to their usual exercise routine on Earth were more likely to recover their bones after a mission. The astronauts lost an average of 2.1% decreased bone density in the lower leg, tibia, and 1.3% decreased bone strength. Use Chrome browser for more accessible video player 1:14 A NASA astronaut has returned to Earth after a record 355 days in space. “During spaceflight, the delicate bone structures become thinner and eventually some of the bone rods become disconnected from each other,” Professor Gabel said. “Once the astronaut returns to Earth, the remaining bone connections may thicken and strengthen, but those disconnected in space cannot be rebuilt, so the astronaut’s overall bone structure is permanently altered.” The research also found that the cardiovascular system is also affected by space travel. “Without gravity pulling blood towards our legs, astronauts experience a fluid shift that causes more blood to pool in the upper body,” Professor Gabel said. “This can affect the cardiovascular system and vision.” Read more: NASA assembles team of scientists to study UFOs despite facing ‘reputational risk’ Solar hedgehog among ‘exciting’ images released by European Space Agency Radiation is also a concern, with astronauts facing greater sun exposure and an increased risk of cancer the farther they travel from Earth. Professor Gabel added: “There is much we still do not know about how microgravity affects human health, particularly on space missions longer than six months, and about the long-term health consequences. “We really hope that bone loss will eventually reach larger missions, that people will stop losing bone, but we don’t know.”
