A study on Bone loss in 17 astronauts who flew to the International Space Station It allows a better understanding of the effects of space travel on the human body and measures to mitigate them, something crucial for possible future missions.
The analysis gathered new data on bone loss in astronauts caused by by the microgravity conditions of space and the degree of recovery of bone mineral density on Earth.
Fourteen male and three female astronauts participated, 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 had an average of 2.1% reduction in bone mineral density in the tibia and 1.3% reduction in bone strength. Nine did not regain bone mineral density after spaceflight, experiencing permanent loss.
“We know that astronauts lose bone on long-duration spaceflight. What’s new is that we’ve followed astronauts for a year after their space trip to understand if and how the bone recovers,” said Leigh Gabel, a professor at the University of Calgary and lead author of the analysis published this week in the journal Scientific Reports.
“Astronauts experienced significant bone loss during six-month spaceflights, a loss we would expect to see in older adults for two decades on Earth, and only regained about half of that loss after a year back on Earth.”Gabel said.
Bone loss is due to the normally weight-bearing bones on Earth they don’t do it in space. Space agencies are going to have to improve countermeasures — exercise and nutrition — to help prevent bone loss, Gabel said.
“During spaceflight, the fine bone structures become thinner and over time some of the bony rods become disconnected from each other. Once the astronaut returns to Earth, the remaining bony connections can thicken and become stronger, but those that were severed in space cannot be rebuilt, so the astronaut’s overall bone structure is permanently changed.”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 belonged to the US space agency NASA, the Canadian Space Agency, the European Space Agency and the Japan Aerospace Exploration Agency.
Space travel poses various challenges for the human body, something that worries space agencies when planning new explorations. “Microgravity affects many body systems, including muscle and bone,” Gabel said.
“The cardiovascular system also undergoes many changes. Without gravity pumping blood to the feet, 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 major health concern for astronauts, as the further away from Earth, the greater the exposure to solar radiation and the risk of cancerGabel said.
The study showed that longer space missions led to both more bone loss and less chance of regaining it later.
By Will Dunham (Reuters)