As humankind evolved, there were a few givens: The presence of oxygen for one, and also gravity. These are both, of course, absent in space. Health data from recent space missions has exposed a variety of ways our bodies go a bit off the rails without the gravity to which we're accustomed. Scientists already knew about the dangers of prolonged exposure to radiation, eyeball-shape changes and vision issues, as well as cardiac issues and muscle- and bone-mass loss.

Now a study published in JAMA Neurology provides new details on how space flight negatively affects the human brain, and in particular its white matter.

  • In microgravity, brain fluids behave differently, winding up in different places in the skull.
  • Astronauts' white matter is affected by being in space and weakens their back-home sense of balance.
  • The study hints at our brains' possible ability to adapt to space conditions.


The deterioration was the same type you'd expect to see with aging, but happened over a much shorter period of time. The findings could help explain why some astronauts have balance and coordination problems after returning to Earth. The effect was especially pronounced among those who'd spent more time in orbit. They were greater with longer spaceflight mission durations, and larger brain changes were correlated with greater balance declines.
University of Florida's Rachael Seidler, an applied physiologist and kinesiologist



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