Astronauts who spend too long in space without gravity return with bigger brains and a higher risk of dementia, a study has found.
Lengthy trips to other planets can cause ventricles in the brain to enlarge, leading to a decline in function, according to scientists at the University of Texas.
Their research, published in the journal Radiology, involved carrying out MRI scans on the brains of 11 astronauts – 10 men and one woman – before and after their trips to the International Space Station (ISS), which appeared to show irreversible damage.
They found that a lack of gravity in space results in blood being redirected from the hands and feet towards the brain, which then increases in volume.
Meanwhile the pituitary gland, which lies at the base of the skull and regulates vital bodily functions, such as hormone levels, shrinks because of the increased pressure being put on it.
These changes can cause conditions such as hydrocephalus and symptoms including difficulty walking, bladder control problems and dementia, the research says.
Scientists are now investigating ways to combat the prolonged lack of gravity in space. One idea was a tool which creates artificial gravity by spinning the astronaut while they are either sitting or lying on their stomach.
It is hoped that analysing the effect of enlarged brain ventricles in astronauts could also lead to better treatments of non-astronauts with hydrocephalus and other related conditions.