Motion Sickness

Motion sickness symptoms can include headache, nausea, dizziness, and cold sweats.

• Motion sickness occurs when the movement that you see is different than what the inner ear senses.
• Motion is a common condition (about 1 in 3 people are highly susceptible)
• Motion sickness symptoms and signs are unpleasant, which usually are nausea, during real or perceived motion.
• Motion sickness is more common in some groups of people than in others. The reason for this is not fully understood. Examples include:
  • People with migraines and vestibular migraines
  • It is more common in women, especially during menstruation or pregnancy
  • Some studies suggest that motion sickness is more common among Asians and Europeans.
• Motion sickness commonly occurs while traveling by boat (seasickness), although any type of travel or motion can induce the condition, for example, cars and buses (carsickness), trains, and plains (airsickness).
• Motion sickness is considered a form of dizziness, and it can influence most people that do not have other health problems.
• Motion sickness is not a disease.
• Although motion sickness can be uncomfortable, typically, it is not a symptom of a serious problem unless prolonged vomiting leads to dehydration or electrolyte abnormalities.
• Without treatment it can lead to dehydration and electrolyte abnormalities may lead to more serious problems such as low blood pressure (hypotension), syncope (fainting), or cardiac arrhythmias. 

Motion sickness can occur during any type of movement that is unintentional. Carsickness, seasickness, and air sickness are examples of motion sickness. Complex types of movement, especially slow movement or movement in two different directions (such as up and down plus back and forth) at the same time (commonly the movements of a boat in rough water) are most likely to cause motion sickness.

The primary symptom of motion sickness is nausea. Vomiting and dizziness may also occur.

Other common signs are:

• Sweating
• Increased salivation
• Ageneral feeling of discomfort and not feeling well (malaise)

The severity of motion sickness and how long it lasts varies, even in the same person on different days. Usually, the symptoms stop when the motion stops, although some people may experience symptoms for up to a few days after an episode of motion sickness. For example, after you get off of the boat or ship, you feel like you are moving even though you are not on the boat.

Studies have shown that some people are more likely than others to experience motion sickness.

• Women are more sensitive to motion sickness than men, and pregnant women are especially at risk for motion sickness.
• Children are commonly affected. The peak incidence for the development of motion sickness is 12 years; infants and children under two are generally not affected.
• People who suffer from migraine headaches or conditions that interfere with sensory input (such as labyrinthitis) are at increased risk for motion sickness.

Usually, motion sickness resolves after the motion has stopped. Rarely, symptoms may persist for up to a few days following the activity. If you have symptoms of motion sickness that persist or worsen over time, call your doctor.

The cause of motion sickness is complex and not fully understood, but most experts believe that it arises due to conflicts in sensory input to the brain. The brain senses motion through different signaling pathways from the inner ear (sensing motion, acceleration, and gravity), the eyes (vision), and the deeper tissues of the body (proprioceptors), for example, muscles. When the body moves involuntarily, such as when riding in a vehicle, there may be conflict among these different types of sensory input to the brain. The sensory apparatus in the inner ear seems to be most critical in the development of motion sickness.

Usually, motion sickness can be treated at home. However, if you have had motion sickness for an extended period, if it worsens, or if you experience severe symptoms, call your doctor!

No tests can diagnose the cause of motion sickness. Usually, it is diagnosed by your symptoms and signs that occur during travel or during any form of passive motion.

Some people who have had multiple and severe experiences with motion sickness have been helped by physical therapy that uses recurrent head movements and visual cues to replicate the environment that induced sickness, but this is not a common form of treatment. This is based upon the principle that habituation to certain movements and motions (getting accustomed to the type of motion) can occur, leading to a decrease in motion sickness over time when repeatedly exposed to the same movements.

• Clinical trials have yielded mixed results concerning the value of acupressure (pressure at the P6 acupressure point on the anterior wrist, located three fingerbreadths proximal to the proximal wrist fold). Manual pressure or pressure using a bracelet or wristband has been reported to be effective for motion sickness in some studies, but other studies have failed to show a benefit.
• Due to the characteristics of the vestibular system, the brain senses motion in a frame of reference centered upon the earth rather than on the individual. Therefore, keeping the eyes fixed upon the horizon or land while on a ship or boat can reduce motion sickness. Likewise, when in a car, individuals prone to motion sickness should sit in the front seat and gaze out the window rather than look at a book, map, or computer.
• Other suggestions include picking the most stable section of a vehicle such as the center or front of a car, bus, or airplane or the cabins near the center waterline of a ship, wearing sunglasses, and/or reclining your head (about 300) and supporting your head. Avoid smells (like exhaust fumes), alcohol, and dehydration, and eat light and bland meals.
• Taking 1-2 grams of ginger orally has been used as an alternative medicine to prevent motion sickness. Studies both in experimental motion sickness and in naval cadets at sea have found that ginger, taken in advance, has reduced the symptoms of motion sickness. It is believed, however, that this benefit is due to the effects of ginger on gastric (stomach) motility rather than suppression of sensory input. 
• Peppermint has also been suggested to reduce motion sickness and some people respond to acupuncture.

Medications can be used that suppress the conflicting sensory input to the brain or help alleviate the symptoms of motion sickness. A number of different classes of medications have been effective in treating motion sickness (see below). Medications are most effective when taken in anticipation of the involuntary motion (for example, 4 hours before boarding a boat or train); they are less effective for symptom relief after the motion has begun.

Antihistamines

Antihistamines have been used to treat motion sickness. The nonsedating antihistamines do not seem to be effective in the treatment of the condition.

Examples of antihistamine medications to treat motion sickness include:

• chlorpheniramine (Aller-Chlor),
• cyclizine (Marezine),
• cyclizine HCI (Bonine for Kids)
• dimenhydrinate (Dramamine, Dramamine Chewable, Driminate),
• diphenhydramine (Benadryl),
• meclizine (Antivert, Bonine, D-Vert, Dramamine II).

Side effects of antihistamine drugs may include:

• Significant sedation
• Drowsiness
• Dry mouth
• Blurred vision and confusion
• Urinary retention in the elderly

Anticholinergics

Scopolamine (Transderm-Scop) is the most well-known medication in this category. It has been shown in clinical trials to be effective at preventing motion sickness. Scopolamine is most commonly administered as a patch applied to the skin.

Side effects are the same as those of the antihistamines. People at risk for angle-closure glaucoma should not take scopolamine.

Antidopaminergics

Promethazine (Phenergan, Pentazine) and metoclopramide (Reglan) are two antidopaminergic drugs that have been successful in managing the motion sickness.

Both medications can cause significant sedation in a few people or movement disorders (for example, torticollis or twisting of the neck, or tongue protrusion).

Ephedrine and some amphetamines have been used both to treat motion sickness and to counteract the sedating effects of other medical treatments. Studies have also shown a beneficial effect of caffeine when administered in combination with other medications for motion sickness.

Benzodiazepines have also been useful for some people with motion sickness, for example:

• alprazolam (Xanax)
• diazepam (Valium)

Anti-nausea (antiemetic) medications have been used to control nausea and vomiting after motion sickness has developed, for example:

• prochlorperazine (Compazine)
• ondansetron (Zofran)

Medications that prevent motion sickness should be taken before travel or movement. Other techniques described previously, for example, acupressure and fixing one's gaze upon landmarks or the horizon may help to prevent or lessen the symptoms of motion sickness. 

Episodes of motion sickness may be prevented; but, it is unclear if it is possible to “cure” someone of all motion sickness; however, its symptoms can be reduced and sometimes prevented.

Usually, motion sickness goes away without treatment when the motion has stopped. There are no long-term complications of the condition. However, prolonged vomiting can lead to dehydration and electrolyte abnormalities, which if left untreated, may lead to more serious problems such as low blood pressure (hypotension), syncope (fainting), or cardiac arrhythmias.