What physical state is characterized by motion sickness?

Motion sickness is primarily characterized by sensations of nausea, which result from conflicts between the sensory signals that the brain receives. When a person is in motion, such as when traveling by car, boat, or plane, the inner ear, eyes, and deeper body parts all send different signals to the brain regarding the movement. For instance, the inner ear may sense movement, but the eyes may be focused on a stationary object inside the vehicle. This discrepancy can lead to confusion in the brain about the body’s position and movement, resulting in symptoms of dizziness, sweating, and, notably, nausea.

While other symptoms can accompany motion sickness, such as dizziness or feelings of fatigue, the predominant and most defining symptom remains nausea. This is why it is recognized as the physical state associated with motion sickness.