A new study funded by NASA unravels what happens to the human brain when astronauts travel to zero gravity or space.
Research published in a peer review journal on Thursday claimed that astronauts who travelled on the International Space Station (ISS) or NASA space shuttle on missions lasting six months experienced significant expansion of the cerebral ventricles, spaces in the middle of the brain containing cerebrospinal fluid.
The study also says that most of the expansion happens in the first six months.
The cerebrospinal fluid protects the brain while removing waste. "When astronauts go to space, fluids within the body shift toward the head and push the brain higher against the skull, causing expansion of the ventricles," the report reads.
The researchers concluded after studying MRI scan data from a sample of 30 astronauts before flying to space and after returning to Earth. The mission duration varied from approximately two weeks to one year, and previous spaceflight experience (0 to 3 previous missions), and time since previous flight (roughly 1 to 9 years).
The crew members should wait at least three years to recover before returning to space.
"We don't yet know for sure what the long-term consequences of this are on the health and behavioral health of space travelers, so allowing the brain time to recover seems like a good idea," said Rachael Seidler, a professor of applied physiology and kinesiology at the University of Florida and an author of the study.