As we enter a new era in space travel, a study looking at how the human brain reacts to traveling outside Earth's gravity suggests frequent flyers should wait three years after longer missions to allow the physiological changes in their brains to reset.
"We found that the more time people spent in space, the larger their ventricles became," said Rachael Seidler, a professor of applied physiology and kinesiology at the University of Florida and an author of the study. "Many astronauts travel to space more than one time, and our study shows it takes about three years between flights for the ventricles to fully recover."