Biology 103
2003 Second Paper
On Serendip

Ever felt carsick, airsick or seasick? Motion sickness is the most common medical problem associated with travel. As a child I was always told that "it was in my head," that if I wanted to, I could make it go away. I was made to believe that motion sickness was a psychological problem. To certain extend it is true that it is in my head, but it is not a psychological defect, but rather, a disorder that occurs when conflicting sensory information is sent to the brain. This mild and self-treatable disorder can affect anyone, but recent studies seem to imply that motion sickness may affect certain groups of people more than others. This paper will discuss the causes of motion sickness and will question the genetic and racial implications as contributing factors.

The anatomy of balance

Balance is maintained by a complex interaction of sensory parts of our body. The first are the inner ears, which monitor the directions of motion (such as side to side, back to front, up and down, and turning). Some people may feel dizzy without having to be spinning or turning. This dizziness is sometimes caused by an inner ear problem. Changes of fluids in the semicircular canals of the inner ear are one of the attributing factors of motion sickness. (1). Second, the eyes monitor where the body is in space and also the direction in which the motion is taking place. Third, the skin pressure receptors (joints and spine) send messages to the brain to inform what part of the body is down and touching the ground. Lastly, the muscle and joint sensory receptors are in charge of informing the brain which parts of the body are in motion. Through the interaction of all these parts, the central nervous system (the brain and the spinal cord) receives and processes all the information sent by the above mentioned four systems to make some sense of coordination. (2) If any of the four sensory systems are not in accordance with the rest of the systems, this resulting conflict thus leads to symptoms of nausea, dizziness, and sometimes vomiting. These symptoms are all pertinent to motion sickness. For example, suppose you are riding on Greyhound for thanksgiving, and decide to read a cookbook. While you are reading recipes, your eyes sense that your body is stationary. Your eyes cannot detect you are moving because you are inside the bus reading a book. However, your skin receptors and your inner ear fluids sense that your body is in motion since you are riding a moving bus. Consequently, your brain receives mixed messages, thus being susceptible to getting motion sickness or "carsick".

Risk Factors

There are risk factors that may increase your chances of getting motion sickness. Those include long or turbulent car, boat, plane, or train rides, amusement park rides, anxiety or fear, smoke or fumes, poor ventilation and having a minor illness, hangover, overeating, or overtiredness in the twenty-four hours before travel. Moreover, the following risk factors seem to have most significance: A) Age; children have a tendency (more than adults) to have motion sickness. In this situation, the cliché "you will grow out of it," is true. B) Family members who get motion sickness. This factor may imply that there exists a genetic link to the disorder. How could genes affect the equilibrium of our sensory systems? There is no clear hypothesis to explain the relation between DNA and motion sickness, but there are medical conditions linked to genetics that affect our sensory systems. Studies have shown that neurological diseases and allergies are genetically linked; both conditions affect the sensory systems. (3)

Upon researching, an article stated "....some families suffer from motion sickness more than others, there is also a racial difference which was shown in a medical trial...the Asian-American children suffered the most sickness..." (4) How could motion sickness affect one race more than another? Or, do Asian-American children travel more than African American children? I think not. This statement was immediately troublesome for me. Motion sickness (as stated above) is caused by a biological conflict influenced by one's moving surroundings. Race is a word used to describe people of different nations and should therefore, not be used or imply that motion sickness is part of one's self identity. It is true that some individuals are naturally prone to motion sickness since childhood (including myself), but this should not be because one is Latino or African-American. In fact, I dismiss the notion that race has anything to with one having motion sickness. Perhaps, it would've been better to investigate the environment and conditions of where people are located; there may be risk factors related to one's location in a geographical space.

1)What Causes Motion Sickness
2)Dizziness and Motion Sickness
3)What's Motion Sickness
4)What Causes Motion Sickness


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