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1. Spaceflight can damage eyesight. As many as half of all U.S. astronauts who were onboard the International Space Station (ISS) suffered from what NASA calls Spaceflight Neuro-ocular Syndrome.
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Researchers aren’t sure exactly what causes it, but it could be related to the widening of brain vesicles or flattening of eyeballs in microgravity.
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2. Microgravity causes bones to lose density and muscles to atrophy. Without gravity pushing on our bones, they have no reason to grow strong.
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3. Your heart changes shape in space. In microgravity, less blood gets circulated in the body, which means the heart softens up and becomes more round.
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4. Space radiation can cause heart disease. Astronauts who ventured to the Moon had a 43 percent higher chance of developing cardiovascular issues than their Earth-bound peers, most likely due to radiation in space.
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5. The damage space travel does to the human body could come down to “Mitochondrial dysfunction.” In a set of studies involving mice and astronauts, scientists found changes in the function of mitochondria, the tiny energy factories of the cell, as a result of the space environment.
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Read more space stories here.