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MOTION SICKNESS

Motion sickness is a normal response to real, perceived, or anticipated movement. People tend to experience motion sickness on a moving boat, train, airplane, automobile, or amusement park rides. Although this condition is fairly common and only a minor nuisance for the occasional traveler, it may be incapacitating for people with an occupation that requires constant movement, such as a flight attendant, pilot, astronaut, or ship crew member. Symptoms generally consist of dizziness, fatigue, and nausea, which may progress to vomiting. Fortunately, most symptoms disappear once the journey is over.

Signs and Symptoms

The most common signs and symptoms of motion sickness include:

Causes

Motion sickness occurs when the body, the inner ear (a tiny structure involved in hearing and balance), and the eyes send conflicting signals to the brain. This reaction is generally provoked by a moving vehicle such as a car, boat, airplane, or space shuttle, 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 perceive, and, conversely, the eyes may perceive movement on a "virtual reality" simulation ride that the body does not feel. Interestingly, once a person adapts to the movement and the motion stops, the symptoms may recur and cause the person to adjust all over again (although, this reaction is generally brief). In addition, even anticipating movement can cause anxiety and symptoms of motion sickness. For example, a person with a previous experience of motion sickness may become nauseous on an airplane before take-off.

Risk Factors

The following are the most common risk factors for motion sickness:

Diagnosis

Most people who have experienced motion sickness in the past ask their healthcare provider how to prevent another episode from occurring in the future; rarely will an individual arrive at his or her healthcare provider's office actually experiencing motion sickness. To establish a diagnosis of motion sickness, the provider will inquire about the individual's symptoms as well as the event that typically causes the condition (such as riding in a boat, flying in a plane, or driving in car). Laboratory tests are generally not necessary to establish a diagnosis of motion sickness.

Preventive Care

The following general measures may be taken to help avoid the discomfort caused by motion sickness:

Individuals who commonly experience motion sickness on a plane should take the following preventive measures:

Individuals with a tendency toward motion sickness on a boat should take the following preventive measures:

Treatment Approach

While medications may be an acceptable treatment for travelers who occasionally experience motion sickness, the goal for individuals who experience motion sickness on a regular basis or whose work is affected by their symptoms is to learn to control–and eventually prevent–these symptoms. This may be accomplished with mind/body practices, such as cognitive-behavioral therapy and biofeedback. Other alternatives to medication include homeopathy, acupuncture, ginger (Zingiber officinale),� dietary adjustments, and physical therapy.

Medications

Medications for motion sickness may cause drowsiness and impair judgement and, therefore, should be avoided in pilots, astronauts, ship crew members, and individuals in any other occupation where heavy equipment is operated or where being alert is critical. The following medications are a reasonable option for infrequent travelers and others who experience motion sickness occasionally:

Nutrition and Dietary Supplements

Generally, small frequent meals are recommended for individuals prone to motion sickness. Dietary records of a small group of novice pilots also indicate that an increase in airsickness (motion sickness from air travel) may be associated with the following:

Herbs

Ginger (Zingiber officinale)

Several studies suggest that ginger may be more effective than placebo in reducing symptoms associated with motion sickness. For example, in one clinical trial of 80 novice sailors (prone to motion sickness), those who took ginger (in powder form) experienced a significant reduction in vomiting and cold sweating compared to those who took placebo. Similar results were found in a study with healthy volunteers. While these results are promising, other studies suggest that ginger is not as effective as medications in reducing symptoms associated with motion sickness. In a small study of volunteers who were given ginger (fresh root and powder form), scopolamine, or placebo, those receiving the medication demonstrated a significant reduction in symptoms compared to those who received ginger. More rigorous trials are needed to confirm the effectiveness of ginger for motion sickness.

Other

Although black horehound (Ballota nigra) and peppermint (Mentha piperita) have not been scientifically studied for their use in treating motion sickness, some professional herbalists may recommend these herbs in combination to alleviate nausea associated with the condition.

Acupuncture

Some preliminary studies suggest that people with motion sickness who receive acupuncture report a significant improvement in symptoms compared to those who receive sham acupuncture (needling at points not indicated for nausea, vomiting, or motion sickness) or no acupuncture at all. Although results have been less convincing, studies also suggest that acupressure may help reduce symptoms of motion sickness in the same way as acupuncture. An acupressure practitioner works with the same points used in acupuncture, but stimulates these healing sites with finger pressure, rather than inserting fine needles.

Massage and Physical Therapy

One case study of a woman with motion sickness suggests that balance training and habituation (reducing or modifying one's response to a stimulus that causes motion sickness) may help diminish the symptoms of the condition. The use of habituation for the treatment of motion sickness is based on the theory that when an individual prone to motion sickness is repetitively exposed to the stimulus that causes motion sickness (such as driving in a car or riding on an elevator) in a controlled, supervised fashion, he or she will habituate, or become used to that stimulus. Over time, the stimulus will no longer evoke the motion sickness response and symptoms will diminish.

Homeopathy

There have been few studies examining the effectiveness of specific homeopathic remedies. A professional homeopath, however, may recommend one or more of the following treatments for motion sickness based on his or her knowledge and clinical experience. Before prescribing a remedy, homeopaths take into account a person's constitutional type. In homeopathic terms, a person's constitution is his or her physical, emotional, and intellectual makeup. An experienced homeopath assesses all of these factors when determining the most appropriate remedy for a particular individual.

Mind/Body Medicine

Biofeedback Training and Relaxation

In a study of 55 pilots who had to stop flying due to symptoms of motion sickness, 76% of them successfully overcame their motion sickness and were able to return to work after participating in a biofeedback training and relaxation program. Biofeedback instruments recorded skin temperature and changes in muscle tension while the pilots were exposed to a stimulus that caused motion sickness (sitting in a tilting, rotating chair). While in the chair, the pilots performed various relaxation techniques, such as deep muscle relaxation and mental imagery. Over time, the pilots habituated to the rotating chair; they no longer felt sick in the chair because they learned to relax in it.

Cognitive-Behavioral Therapy

The goal of cognitive-behavioral therapy is to alleviate the anxiety that some people experience simply thinking about movement or motion sickness. In a study of 50 pilots who occasionally experienced motion sickness, 86% of them successfully overcame their symptoms after cognitive-behavioral therapy. During cognitive-behavior therapy, individuals are exposed to a provocative stimulus (such as a tilting, rotating chair) in a slow, and controlled fashion until they experience some symptoms of motion sickness, but not until they are overwhelming. As the individual performs better and better on the rotating chair, his or her confidence builds and anxiety lessens.

Breathing Techniques

In a study of 46 people with motion sickness, those who were instructed to take slow, deep breaths had a significant reduction in symptoms of motion sickness compared to those who breathed normally or counted their breaths. Interestingly, involuntary rapid and shallow breathing often exacerbates symptoms of motion sickness. While it makes sense that slow, deliberate breathing would help reduce the anxiety associated with motion sickness, further studies are needed to determine whether breathing techniques effectively diminish the symptoms associated with the condition.

Traditional Chinese Medicine

Pingandan

One small animal study suggests that Pingandan, a Chinese herbal mixture, may significantly reduce signs of motion sickness (including defecation, urination, salivation, panting, and drowsiness). Pingandan primarily consists of:

While individuals who have used the herbal remedy report fewer side effects than those who take scopolamine, more studies are needed to determine whether Pingandan is a safe and effective therapy for motion sickness.

Other Considerations

Pregnancy

Due to a lack of clinical evidence, there is some controversy regarding the safety of ginger taken during pregnancy. In one study of pregnant women, more than 70% reported less morning sickness while taking 250 mg of ginger 4 times per day compared to those who received placebo. Therefore, healthcare practitioners recommend limiting intake of ginger to this amount if used during pregnancy.

Prognosis and Complications

While motion sickness has no long-term complications, the condition may be devastating for those in an occupation that involves constant movement, such as a flight attendant, pilot, astronaut, or ship crew member.

The symptoms of motion sickness generally disappear quickly once the journey (such as a moving boat, train, airplane, or automobile) is over. People who travel infrequently may also become accustomed to movement during a trip lasting several days. Even those who travel often may improve from repeated exposures to the same type of experience. However, people who become anxious before a journey often experience worsened symptoms of motion sickness and tend to require more formal interventions, such as biofeedback and relaxation training.