Cause and Risk Factors for Motion Sickness
Motion sickness occurs when nerves that sense movement send inconsistent signals to the brain. For example, when riding in a moving car, the inner ears sense motion, but unless the person can see out the window, his or her eyes do not see and confirm this movement. As a result, the person may become car sick.
Motion sickness also can occur in response to perceived movement, such as in a "virtual reality" game or experience, or while watching a movie with a lot of fast motion. In this situation, the eyes sense motion, but the inner ears and nerve receptors in the skin, muscles, and joints do not, producing motion sickness.
Motion sickness occurs more often in some people than in others. The reason for this is unclear, but it may be related to an increased brain response to movement. A person who gets car sick often experiences other types of motion sickness, including sea sickness and air sickness, especially on his or her first boat or plane ride.
Motion sickness usually is more severe when movement is intense, such as on a bumpy car ride or a winding road, in rough seas, or in turbulent air. Anxiety, stress, fatigue, and excitement can contribute to and increase motion sickness symptoms. Once a person experiences motion sickness, he or she may become worried before traveling, worsening the problem.
Motion sickness usually improves as the child gets older; however, there appears to be a link between childhood motion sickness and the development of migraine headaches later in life.