Motion Sickness

Motion sickness (also known as car, sea, train, or air sickness) involves a group of symptoms, particularly nausea, caused by movement during travel.

Motion sickness occurs when the brain receives contradictory information from its motion sensors--the eyes, the semicircular canals in the inner ear (which help control balance), and the muscle sensors that provide information about body position. Motion sickness commonly occurs during boat travel, when the boat rolls and rocks. It may also occur in a moving car, amusement park rides, or other moving vehicles. Some people are more susceptible than others. Fear, anxiety, and poor ventilation increase the likelihood of experiencing motion sickness.

Symptoms and Diagnosis

Symptoms begin relatively suddenly. Nausea, a feeling of general discomfort, vertigo, headache, and fatigue usually develop. The face becomes pale, and the person starts to sweat and feel unpleasantly warm. Vomiting often occurs. Other symptoms may include increased saliva production (often as a prelude to vomiting) and rapid, deep breathing (hyperventilation). Hyperventilation may produce faintness. Nausea and vomiting make the person feel weak. Prolonged vomiting can lead to low blood pressure and dehydration. However, symptoms tend to gradually subside when the motion stops or the person leaves the vehicle. Also, people who are on long trips, as on a ship, usually adapt to the motion (helped by the stabilizers used in modern ships to minimize motion) and gradually recover.

Motion sickness is diagnosed based on a description of the symptoms and the circumstances in which they occur.

Prevention and Treatment

Prevention is key. Measures include

Choosing a seat where motion is felt least (such as the front seat of a car, a seat over the wings in an airplane, or the forward or middle cabin or upper deck of a ship)
Keeping the head and body as still as possible
Sitting face forward and in a reclining position
Keeping the eyes on the horizon or another distant, unmoving object
Not reading
Getting fresh air by opening a window, opening an air vent, or going to a ship's top deck
Not drinking alcoholic beverages and not smoking (both can aggravate nausea)
Eating small amounts of low-fat, starchy foods and not eating strong-smelling or strong-tasting foods
Avoiding food and drink on short airplane trips, especially on small airplanes

Before traveling, people who are susceptible to motion sickness can ask their doctor to recommend an over-the-counter drug or prescribe a drug to prevent the disorder. These drugs include cyclizine, dimenhydrinate, diphenhydramine, meclizine, perphenazine, and scopolamine. All of these drugs cause drowsiness but may cause agitation in infants and very young children and should not be given to them except under a doctor's supervision (see Section 2, Chapter 18).

If motion sickness develops, eating soda crackers or drinking carbonated soda, such as ginger ale, may help. Because of the nausea, scopolamine, the only drug for motion sickness that is given through a skin patch, is often more useful than other drugs, which are taken by mouth. Drugs can also be given by injection if necessary.