The human body has no business being in space. Without the familiar tug of gravity, bones can decalcify, muscles can atrophy, blood pressure can plunge, heart rate can grow erratic, and fluids can rise and pool in the head, leading to pain, congestion, vision problems, and even kidney stones as less water is flushed and excreted as urine. Exercise and proper hydration can alleviate some of these problems, but any stay in space can still exact a price—especially the long, six- to 12-month shifts that many space station astronauts pull. And that’s only the physical toll. Less studied, but no less worrisome, is what long-duration space flight can do to an astronaut’s cognitive abilities.
Now, a new study published in Frontiers in Physiology has some answers—mostly encouraging. While the brain, like the rest of the body, can take a hit when it leaves the planet, the investigators found that astronauts for the most part keep their intellectual and behavioral wits about them, adapting dependably, if sometimes slowly, to their rarefied surroundings.
The research, led by neuropsychologist Sheena Dev, of NASA’s behavioral health and performance laboratory, was extensive. It involved 25 astronauts who underwent a battery of 10 different cognitive tests before, during, and after six-month rotations aboard the International Space Station. The subjects sat for the first set of tests 90 days before leaving Earth. This provided a baseline against which their later performance could be measured. They followed that up by repeating the exercises during their first and last months aloft, and then again ten days and 30 days after returning to Earth.
There were a lot of reasons to expect the subjects’ performance to suffer as a result of their time in space. Among the psychological and emotional factors Dev and her colleagues considered were isolation, confinement, distance from home, overwork, disruption of circadian rhythms, and sleep deprivation.
“Even on Earth,…
