Motion sickness is a normal response to real, perceived, or even anticipated movement. People tend to get motion sickness on a moving boat, train, airplane, car, or amusement park rides. Although this condition is fairly common and often only a minor nuisance, it may be incapacitating for people who travel frequently -- although the more you travel, the more you get used to the motion.
Motion sickness and vestibular dysfunction are reported in a substantial percentage of astronauts. 70% of astronauts during spaceflight, and involves motion sickness, changes in olfactory and gustatory sensory function and, ultimately, decreased energy intake. Motion sickness results because an astronaut in orbit experiences a mismatch between what is perceived by the eye and what is sensed by inner ear. This sensory-motor disconnect causes disorientation and affects astronauts for the first 2-3 days of orbit. Many astronauts report a diminished or drastic change in their sense of taste during spaceflight. Symptoms of nausea, vertigo and disorientation occur shortly after liftoff and last 3 to several days.
Signs and Symptoms
The most common signs and symptoms of motion sickness include:
- Paleness of the skin
- Cold sweats
- Increased salivation
Motion sickness occurs when the body, the inner ear, and the eyes send conflicting signals to the brain. This most often happens when a person is in a moving vehicle such as a car, boat, or airplane, but it may also happen on flight simulators or amusement park rides. From inside a ship's cabin, the inner ear may sense rolling motions that the eyes cannot see, and, conversely, the eyes may see movement on a "virtual reality" simulation ride that the body does not feel. Interestingly, once a person gets used to the movement and the motion stops, symptoms may return (although usually only briefly). Sometimes just anticipating movement can cause anxiety and symptoms of motion sickness. For example, a person who had previously had motion sickness might become nauseous on an airplane before take-off.