| Space Adaptation Syndrome |
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Space adaptation syndrome, also called space motion sickness, is very common in astronauts. It occurs when there is a discrepancy of information between visual input and the vestibular apparatus. Astronauts can take drugs or undergo autogenic feedback training to handle this motion sickness. After approximately three days, the brain automatically adapts by relying on visual input alone.
Just as the pitching and rolling of a boat in water causes one to become seasick, motion sickness in space causes one to become spacesick, or experience space motion sickness. Motion sickness is an equilibrium disorder caused by a mismatch of information between visual input from the eyes and the vestibular apparatus located in the ear.
The vestibular apparatus contains a fluid and tiny hairs that move with the pull of gravity to inform the brain of the orientation and direction of movement of the body. In microgravity, the vestibular apparatus can not function properly. For example, when an astronaut is upside down, his eyes indicate this to his brain, but his vestibular apparatus does not provide interpretable information. This can result in dizziness, nausea, and vomiting for a few days until the brain adapts by relying on visual input alone. NASA studies indicate that approximately half of the US astronauts experience space adaptation syndrome.
Space travelers can take drugs to prevent or lessen motion sickness. These drugs target the neurotransmitters that stimulate vomiting. Another way to handle space adaptation syndrome is through autogenic feedback training, which involves controlling bodily functions that are usually involuntary. This enables astronauts to learn to prevent or minimize motion sickness and other conditions caused by microgravity.
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