Prolonged spaceflight can lead to major changes in the human brain. Researchers studied brain scans of 30 astronauts before and after space travel and found that the ventricles of the brain expanded significantly in those who had longer missions of at least six months.
The ventricles are cavities in the brain filled with cerebrospinal fluid that provide protection, nutrition, and removal of brain waste. Mechanisms in the human body effectively distribute fluid throughout the body, but in the absence of gravity, the fluid moves upward, pushing the brain higher inside the skull and causing the ventricles to expand.
“We found that the more time people spent in space, the larger their ventricles became,” said Rachel Zeidler, professor of applied physiology and kinesiology at the University of Florida and author of the study. – “Many astronauts go into space more than once, and our study shows that it takes about three years between flights for the ventricles to fully recover.”
Of the 30 astronauts, eight had two-week flights, 18 had six-month flights and four had been in space for about one year. The study authors reported that the ventricles shrank after six months.
These changes could affect future decisions about crew travel and mission planning. For example, frequent flyers should wait three years after long flights for their brains to recover.
“We were pleased to see that the changes don’t increase exponentially, given that eventually people will be in space for longer periods of time,” Rachel Zeidler said.
Although space travel is becoming increasingly affordable, research shows that we are not yet ready for long-term space travel. But scientists are still working on this problem, and perhaps in the future we will find ways to better protect the human brain from the effects of weightlessness.