Astronauts’ brains suffer during long space flights

(CNN) Space flights of six months or more take a toll on astronauts’ brains, and crew members may need to wait at least three years before returning to space, according to a new study.

The scientists compared brain scans of 30 astronauts taken before spaceflights lasting two weeks, six months or a year with those taken after their return to Earth. The scans revealed that the ventricles, or brain cavities filled with cerebrospinal fluid, expanded significantly in the brains of astronauts who traveled to the International Space Station on missions lasting at least six months.

The results have implications for future long-term missions, as NASA and its international partners aim to establish a sustained human presence on the Moon with the Artemis programwith the ultimate goal of sending humans to deep space destinations like mars. Scientific Reports magazine posted this thursday a study detailing these findings.

Cerebrospinal fluid protects and nourishes the brain, while removing waste. But when astronauts go into space, bodily fluids travel to the head and push the brain against the skull, causing the ventricles to dilate.

“We found that the more time people spent in space, the larger their ventricles became,” said the study’s lead author, Rachael Seidler, a professor of applied physiology and kinesiology at the University of Florida, in a statement. “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.”

Eight of the study astronauts flew two-week missions, while 18 ventured on six-month missions. Four astronauts had missions that lasted about a year. During the analysis, the researchers determined that the degree of enlargement of the ventricles varied depending on the time the astronauts were in space.

“The biggest jump is when you go from two weeks to six months in space,” said Seidler, who is also a member of UF Health’s Norman Fixel Institute for Neurological Diseases.

There was no further increase between six months and one year, which means that ventricular enlargement appears to decrease after six months, which surprised the researchers, Seidler said. “This is good news for future travelers to Mars, who could end up spending (approximately) two years in microgravity.”

And the impact was minimal for the astronauts who traveled in space for two weeks, a welcome finding for the commercial space industry as costs rise. short duration space tourism flights.

“People who spend just a couple of weeks show little to no change in these structures,” Seidler said. “This is good news for those who take short-duration spaceflights.”

Recovery time after space travel

In 11 of the astronauts, all of whom had more than three years to recover between missions, the researchers noted increased ventricular volume after each of their most recent missions. Seven of the astronauts with the shortest recovery period between missions showed little ventricular augmentation after their most recent flight.

Although this finding seems positive, it suggests that the brains of experienced astronauts have ventricles that remain enlarged before their next mission and “have less available space or compliance for ventricular expansion with spaceflight,” the authors wrote in the study.

The scientists don’t know how long it takes for the ventricles to fully recover after spaceflight, but their analysis showed that astronauts experienced a 55% to 64% recovery toward their preflight levels six to seven months after spaceflight. six-month mission to the space station.

Based on the research results, the team concluded that astronauts need at least three years between missions to allow their ventricles to fully recover.

The results could help NASA and other space agencies plan future missions, but Seidler says more research is needed. She is starting work on a new project that will study long-term health and recovery for up to five years after six-month spaceflights.

“We still don’t know for sure what the long-term consequences are for the health and behavior of space travelers, so giving the brain time to recover seems like a good idea,” he says.

“The findings may suggest that three years are needed for recovery. However, astronauts have very specialized training and skills and additional missions may be justified before this time.”