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Motion Sickness

Motion Sickness Overview

Motion sickness (kinetosis) is the experience of unpleasant symptoms, predominantly nausea, during real or perceived motion. It is most commonly observed in boat travel (seasickness), although any type of travel or motion can induce motion sickness. Other examples of motion or travel sickness include car sickness and air sickness.

Motion sickness is considered to be a form of dizziness and can be induced in most normal individuals. It is not considered to be a specific disease state. Although motion sickness can be uncomfortable, it is typically not a sign of a serious problem unless prolonged vomiting leads to dehydration or electrolyte abnormalities.

Motion Sickness Causes

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). 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.

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.

  • Persons who suffer from migraine headaches or conditions that interfere with sensory input (such as labyrinthitis) are at increased risk for motion sickness.


Next: Motion Sickness Symptoms »

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Motion Sickness

Dehydration in Adults Overview

Dehydration is a condition that occurs when the loss of body fluids, mostly water, exceeds the amount that is taken in. With dehydration, more water is moving out of our cells and then out of our bodies than the amount of water we take in through drinking.

We lose water every day in the form of water vapor in the breath we exhale and as water in our sweat, urine, and stool. Along with the water, small amounts of salts are also lost.

When we lose too much water, our bodies may become out of balance or dehydrated. Severe dehydration can lead to death.

 

Causes of Dehydration in Adults

Many conditions may cause rapid and continued fluid losses and lead to dehydration:

  • Fever, heat exposure, and too much exercise

  • Vomiting, diarrhea, and increased urination due to infection

  • Diseases such as ...

Read the Dehydration (Adults) article »



Medical Dictionary