A study led by astronauts has revealed the devastating impact of space travel on human skeletons.
The study found that astronauts lost “significant” bone during six-month spaceflight – the equivalent of about two decades on Earth.
Only about half of the lost bones were recovered a year after the return – raising concerns about future missions to Mars and the Moon.
Longer space missions lead to increased bone loss and reduced resilience.
Bone loss occurs due to the lack of gravity in space, where weight-bearing bones on Earth normally have no weight.
The study was carried out on 17 astronauts – 14 men and 3 women with an average age of 47 – who flew on International Space Station (ISS) for the past seven years.
Crew from the US space agency NASACanadian and European Space Agency, and Japan Aerospace Exploration Agency.
They worked with a research team led by University of Calgary professor Leigh Gabel for a year after returning to Earth.
Nine crew members have experienced a permanent loss of bone mineral density after spending between four and seven months on space missions.
“Astronauts experienced significant bone loss during their six months of space flight – a loss we would expect to see in people who have been older than two decades on Earth, and they have only recovered. about half of those bones after a year of returning to Earth,” Professor Gabel said. study, published in the journal Scientific Reports.
“We know that astronauts lose bones on long-duration spaceflight.
“What’s novel about this study is that we followed the astronauts for a year after their spaceflight to understand if and how the bones recovered.”
Space agencies must improve countermeasures, such as exercise and nutrition, to prevent bone loss, Professor Gabel warned.
Research shows that in-flight exercise including resistance training aboard the ISS is shown to be important for preventing bone and muscle loss.
Astronauts who completed more deadlifts than their usual exercise routine on Earth were more likely to recover from a mission.
Astronauts lost an average of 2.1% loss of density in the shin bones, tibia and 1.3% decrease in bone strength.
Professor Gabel said: “During spaceflight, the small bone structures thinned, and eventually some of the rods separated from each other.
“Once an astronaut returns to Earth, the remaining bone connections can thicken and strengthen, but those disconnected in space cannot be rebuilt, so the total bone structure the astronaut’s body will change forever.”
Research also shows that the cardiovascular system is also affected by space travel.
Professor Gabel said: “Without gravity pulling blood towards our legs, astronauts experience a fluid shift that causes more blood to pool in the upper body.” “This can affect the cardiovascular system and vision.”
Radiation is also a concern, as astronauts face increased exposure to the sun and increased cancer risk as they travel further from Earth.
Professor Gabel added: “There’s a lot we still don’t know regarding how microgravity affects human health, especially during space missions longer than six months and about long-term health consequences.
“We really hope that eventual bone loss will be higher on longer missions, that people will stop losing bone, but we don’t know.”