Space travel makes bones weak, study reveals effects on astronauts
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Loading... - Farida Jabrane
- 04 Jul 2022
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Space travel is not easy. It's isolating, lonely, full of challenges, and above all, extremely risky and at times even life-threatening. A new study reveals the toll it takes on human health and as countries push for longer and deeper human space exploration missions, it could pave the way to better understand changes in human physiology while in zero gravity.
The study focussed on bone loss in astronauts while traveling in space and revolved around analysing bone strength, density, and microarchitecture using high-resolution computed tomography, where researchers imaged the tibia and radius before spaceflight, at return to Earth, and after 6 and 12 months recovery.
The detrimental effect of spaceflight on skeletal tissue can be profound, with decreases in mechanical loading in microgravity causing substantial loss of bone mineral density and strength. It could also lead to deterioration of trabecular microarchitecture, and biochemical studies of bone turnover highlight altered bone metabolism during spaceflight.
The study published in the journal Scientific Reports revealed 2.1 per cent reduction in bone mineral density at the tibia - one of the bones of the lower leg - and 1.3 per cent reduction in bone strength.
Researchers analysed 17 astronauts, of which 14 were males and three were female with an average age of 47 years. Their missions ranged from four to seven months in space, with an average of about 5.5 months. The astronauts flew on the space station in the past seven years.
"Twelve months after flight, group median tibia bone strength, bone mineral density, volume fraction, and thickness remained 0.9% to 2.1% reduced compared with pre-flight. Astronauts on longer missions had a poorer bone recovery," the paper said. Nine astronauts did not recover bone mineral density after the space flight, experiencing permanent loss.
"We know that astronauts lose bone on long-duration spaceflight. What's novel about this study is that we followed astronauts for one year after their space travel to understand if and how bone recovers," Professor Leigh Gabel, an exercise scientist who was the lead author of the research said.
The bone loss occurs because bones that typically would be weight-bearing on Earth do not carry weight in space. Space agencies are going to need to improve countermeasures - exercise regimes and nutrition - to help prevent bone loss, Gabel said.
He added, "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 they only recovered about half of that loss after one year back on Earth." Read More...
