Posted on January 12 2015
A page written by Dr. Rupa Mukherjee, gastroenterologist at Beth Israel Deaconess Medical Center in Boston, on the link between nausea and the gastrointestinal system.
Motion Sickness is no walk in the park!
People feel it in cars, airplanes, boats, amusement park rides, from movies, flight simulators, and even video games! Have you experienced it?
Nausea is the principle symptom of motion sickness in addition to dizziness and fatigue, and it is experienced by roughly 50% of healthy individuals exposed to provocative motion. Interestingly, the word ‘nausea’ derives from the Greek word nausia or nautia, literally meaning ship-sickness, an apt description for anyone who has experienced a bumpy boat ride. Motion sickness does not have long-term consequences but can leave people feeling pretty miserable. And unfortunately, motion sickness tends to occur more frequently in women, the elderly and people who suffer from migraine headaches.
Motion sickness is very common
Motion sickness can be induced in nearly all adults but individual susceptibility is variable. For example, in a study of nearly 20,000 passengers on 114 boat rides, 21% had nausea, 7% experienced vomiting, and 4% felt “absolutely awful.” I can only imagine. Similar findings were seen in 923 passengers on 38 commercial air flights with nearly 25% of the passengers reporting nausea and malaise. Clearly, motion sickness is a common problem and no walk in the park!
What is happening in the body during motion sickness?
The body has a system of sensing balance that is composed of the inner ear, eyes and sensory nerves. The brain senses movement by getting signals from these organs as well as the muscles and joints. Motion sickness occurs when one part of this system senses motion while the other parts do not. For example, in a windowless cabin in a moving boat, the inner ear senses motion, such as choppy waves, although the eyes cannot see this motion. When watching an IMAX movie or playing video games, the eyes see motion on the screen while the inner ears do not sense this motion since you are sitting in your seat. Motion sickness is actually a common problem for the new 3D goggles that companies like Oculus are coming out with. This mismatch in the senses leads to motion sickness.
Motion sickness can also occur when motion is both seen and felt but the signals sent to the brain do not correspond. A good example of this is riding slowly in a car on a badly maintained road. Due to the poor road quality, every bump and pothole will induce a sense of severe motion to the inner ear but due to the slow speed, the eyes do not sense a proportional amount of motion.
How does motion sickness cause nausea?
The sensation of nausea due to motion is a result of interactions between the central nervous system and the stomach. The stomach normally produces “slow waves” at 3 cycles/minute that help control the movement of food through the gastrointestinal tract. When you are on a boat or car, circular vection may increase the rate to 4-9 cycles/minute or greater. This increased rate leads to the perception of nausea. Therefore, interventions that can prevent the development of this “dysrhythmia” can help treat the symptoms of motion sickness.
You can beat motion sickness!
The good news is that motion sickness usually quiets down as soon as the motion stops. However, if you can’t stop the motion, you can reduce the feelings of queasiness by closing your eyes, napping or chewing gum in the case of mild car sickness. It is also helpful to look at the horizon in the direction of travel on a boat or look out of the window in a moving vehicle to reorient your inner sense of balance with the movement that your eyes are seeing.
There are also medications to treat motion sickness. However, they often treat symptoms incompletely and can have side effects, such as extreme drowsiness. This is not ideal or viable for many. And many boats, for example, are not allowed to sell these medicines on-board. Alternative non-pharmacologic treatments such as protein, ginger, and other ingredients have been found to be effective in clinical research studies on nausea and motion sickness. In future blogs, I will further explore the role of ginger and protein in controlling symptoms of motion sickness.
Golding JF, Gresty MA. Pathophysiology and treatment of motion sickness. Curr Opin Neurol 2015. 28(1): 83-8.
Kock KL. Gastric dysrhythmias: a potential objective measure of nausea. Exp Brain Res 2014. 232(8):2553-61.
Stern RM, Koch KL, Stewart WR et al. Spectral analysis of tachygastria recorded during motion sickness. Gastroenterology 1987. 92(1):92-7.