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Astronaut Mark Vande Hei takes a space selfie.
Staying in space has consequences for your health
Photo: NASA
A prolonged stay in space not only causes astronauts' muscles and bones to shrink.
Life in weightlessness apparently also has an impact on the human brain.
An international team of scientists examined the blood of five astronauts on their return from the ISS.
According to their own information, the researchers were able to demonstrate that several proteins, which indicate aging processes and injuries to the brain, increase significantly immediately after returning from space.
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The blood samples were compared with samples taken before the start of the mission.
In addition, the researchers checked the blood values of the astronauts one and then again three weeks after they landed on earth.
According to the researchers, the proteins indicate an injury to the long nerve fibers in the white matter and the supporting tissue of the brain, the glia.
The increase in blood values for a protein that indicates brain aging correlates in its level with the length of stay in space.
The cause of the increase in brain proteins may be a disturbed outflow of venous blood from the head in weightlessness, which over time leads to an increase in pressure in the nerve water.
"A mild but persistent brain injury"
Since the behavior of very different proteins was very similar, the researchers assume a comprehensive overall reaction of the entire brain after a long stay in weightlessness, not just from the change in one type of tissue alone.
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"Overall, our results indicate a mild but persistent brain injury and an accelerated aging process of the brain on return to earth," said the physician Professor Peter zu Eulenburg from the Ludwig Maximilians University in Munich.
"All relevant types of tissue in the brain seem to be affected."
So far, only changes in the eyesight of some space travelers had provided a clinical indication of neurologically relevant consequences of a long stay in space.
How dangerous would the flight to Mars be?
Knowing how great the health threats to the human body are in space is also important for future visits to Mars.
The first human could set foot on the surface of Mars as early as 2033.
"In order to minimize the neurological risks during long-term missions and to determine the general clinical significance of the findings, more comprehensive studies with preventive measures against the rise in pressure in the head are absolutely necessary before space travelers embark on a trip to Mars," said zu Eulenburg.
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