Motion Sickness

Motion sickness occurs when certain kinds of motion make an individual feel ill. The symptoms of motion sickness can occur in response to real motion (e.g., travel by car, boat, airplane, or train) or in response to a perceived sense of motion, such as when watching movies on large screens or using virtual reality (VR) simulators, as well as during space travel. 

Motion sickness is not a disorder. Instead, it is a physiological response anyone can have when experiencing real or perceived motion. Although all people can develop motion sickness if exposed to a sufficiently intense stimulus, some people are more susceptible than others. In general, it seems that females, children between the ages of 2 and 15, and those with conditions associated with nausea (e.g., early pregnancy, migraines, vertigo) are more susceptible to motion sickness.

Motion sickness typically arises from inconsistencies between the sensory systems involved in the perception of motion, including the vestibular, visual, and proprioceptive systems. The vestibular system (i.e., inner ear balance mechanism) is responsible for one’s sense of balance and movement direction; while the proprioceptive system carries sensory information from the joints and muscles all over the body. 

With motion sickness, there is often a mismatch between what the eyes, the muscles and joints, and the vestibular organs in the inner ear sense. For instance, motion sickness may strike when a person is reading a book while traveling by car. The vestibular system senses that the body is moving with the car, while, at the same time, the eyes tell the brain that the book being read is not moving. Since the nervous system is perceiving conflicting information, it may result in the feeling of sickness. Similarly, motion sickness may occur when the visual system detects motion while the body remains still. This is known as visually-induced motion sickness, and it may occur during virtual reality simulation or while watching movies on large displays. 

The earliest symptom of motion sickness is usually a feeling of discomfort in the abdomen, known as stomach awareness. This is often followed by nausea and vomiting. Some individuals may also experience a cold sweat, increased salivation, headache, spatial disorientation (i.e., the inability to determine one’s position in space), and a sense of drowsiness that may persist well after the motion stimulus has ended. In rare cases, severe symptoms, such as the inability to walk, persistent vomiting, or a desire to be left alone, may also occur. 

Motion sickness is often self-diagnosed, based on a history of symptoms triggered by traveling or other kinds of motion, such as being on an amusement park ride. If the clinical presentation is clear, further laboratory or imaging tests are generally not necessary to confirm the diagnosis. However, if the diagnosis is unclear, other tests may be performed to rule out conditions that may resemble motion sickness, including vestibular disorders (e.g., vestibular migraine, benign paroxysmal positional vertigo, infection of the inner ear) or a posterior circulation stroke.

Certain behavioral strategies are often recommended to help prevent and minimize the symptoms of motion sickness, as it is easier to prevent motion sickness than it is to relieve the symptoms.

Some of these behavioral strategies include avoiding travel in bad weather conditions (e.g., during storms) and, when traveling, sitting in areas that experience the least amount of movement. This is usually the lowest level in trains and buses, over the wing on airplanes, and close to water level in boats. Other tips that may help prevent motion sickness include sitting in the front seat of the car, looking at a fixed point in the horizon, and avoiding focusing on phones or other screens, maps, or books while traveling in a moving vehicle. 

If symptoms are severe or persist despite behavioral changes, medications may be recommended. Some medications used for treating motion sickness are over-the-counter (OTC) antihistamines (e.g., dimenhydrinate, cyclizine, and meclizine) as well as scopolamine, a prescription anticholinergic medication. 

While antihistamines are widely used, they may result in a variety of side effects, including increased sleepiness, drowsiness, blurred vision, dry mouth, and urinary retention. Meanwhile, scopolamine, which is often available as a patch that can be placed behind the ear, can cause dilated or widened pupils (i.e., mydriasis), blurry vision, and dry mouth. In general, these medications work best if taken at least one hour before traveling, or as soon as possible after the onset of the symptoms. 

Symptoms of motion sickness can occur within minutes of experiencing motion and may persist for hours after the motion stimulus has ended. The severity of the symptoms varies from person to person, depending on the intensity of the stimulus and the unique susceptibility of each individual. 

Motion sickness is a common condition characterized by a feeling of sickness triggered by certain kinds of movement. Motion sickness can occur with any mode of travel (e.g., car, train, boat, airplane), during amusement park rides, and even in virtual reality (VR) environments, such as in video game simulators. Common symptoms include stomach awareness, nausea and vomiting, drowsiness, and spatial disorientation. Motion sickness can be diagnosed based on a compatible medical history and exclusion of more severe conditions. In most cases, behavioral strategies, like sitting in the front seat of the car or focusing on a fixed point in the distance, are most effective at preventing motion sickness. Individuals with more severe or persistent symptoms may find relief through over-the-counter medications (i.e., first-generation antihistamines) or a prescribed medication, such as scopolamine.