Motion/travel sickness or Kinetosis


Motion sickness or kinetosis is the most common medical problem associated with travel, usually affecting people over many years.  It can occur during any type of travel and I am personally a victim of this condition.

According to MedicineNet, “Motion sickness is a very common disturbance of the inner ear that is caused by repeated motion such as from the swell of the sea, the movement of a car, the motion of a plane in turbulent air, etc. In the inner ear (which is also called the labyrinth), motion sickness affects the sense of balance and equilibrium and, hence, the sense of spatial orientation.”

What causes motion sickness

According to the NHS’s Choices Information booklet, “Motion sickness is thought to occur when there is a conflict between what your eyes see and what your inner ears, which help with balance, sense. Your brain receives a jumble of contrasting information, which is thought to bring on the symptoms of motion sickness.”

This is explained in a lucid manner MedicineNet’s article on the subject matter :

“Motion is sensed by the brain through three different pathways of the nervous system that send signals coming from the inner ear (sensing motion, acceleration, and gravity), the eyes (vision), and the deeper tissues of the body surface (proprioceptors). When the body is moved intentionally, for example, when we walk, the input from all three pathways is coordinated by our brain. When there is unintentional movement of the body, as occurs during motion when driving in a car, the brain is not coordinating the input, and there is thought to be discoordination or conflict among the input from the three pathways. It is hypothesized that the conflict among the inputs is responsible for motion sickness.”

The fact that motion sickness happens when the body, the inner ear, and the eyes send conflicting signals to the brain can be exemplified as put in an article on University of Maryland Medical Centre’s Complementary Medicine page, “This most often happens when you are in a car, boat, or airplane, but it may also happen on flight simulators or amusement park rides. From inside a ship’s cabin, your inner ear may sense rolling motions that your eyes cannot see. On the other hand, your eyes may see movement on a “virtual reality” ride that your body does not feel. Once a person gets used to the movement and the motion stops, symptoms may come back (although usually only briefly). Sometimes just thinking about movement can cause anxiety and symptoms of motion sickness. For example, a person who had motion sickness before might become nauseous on an airplane before take-off.”

To understand the causes of motion sickness, it is useful to know about the vestibular system.  The NHS Choices leaflet explains this system as: “The vestibular system is a complex combination of nerves, small channels and fluids inside your inner ear. It gives your brain a sense of balance and motion. For example, if you stand up and walk towards your front door, the position of the fluids inside your vestibular system will change. The vestibular system transmits information about the changes in the position of the fluids to your brain, so that it knows exactly how and where you are moving. This allows the rest of your body to maintain balance.” Most experts support the theory that motion sickness is caused by a conflict of information between your senses. They put forward the following supporting ideas to validate their claims:

“Your brain holds details about where you are and how you are moving. It constantly updates this with information from your eyes and vestibular system. However, if the messages from these two senses conflict, your brain cannot update your current status and the resulting confusion will lead to the symptoms of motion sickness. For example, if you are travelling by car, motion sickness can occur because your brain cannot cope with the conflicting information from your eyes and your vestibular system. Your eyes tell your brain that you are travelling at more than 30 miles an hour, but your vestibular system tells your brain that you are sitting still. This mismatch of information can lead to the symptoms of motion sickness, such as nausea and vomiting.”

The cause of motion sickness is complex, however, and the role of conflicting input is only a hypothesis, or a proposed explanation, for its development. According to  article on MedicineNet, “Without the motion-sensing organs of the inner ear, motion sickness does not occur, suggesting that the inner ear is critical for the development of motion sickness. Visual input seems to be of lesser importance, since blind people can develop motion sickness. Motion sickness is more likely to occur with complex types of movement, especially movement that is slow or involves two different directions (for example, vertical and horizontal) at the same time.”

How common is motion sickness?

It is thought that everyone can potentially get motion sickness, but that some people are more vulnerable than others. Most studies how that about 33% of people are susceptible to motion sickness even in mild circumstances such as being on a boat in calm water, although nearly 66% of people are susceptible in more severe conditions.

For example, almost everyone on a ship in very rough seas would be expected to have motion sickness. However, about 3 out of 10 people may also have symptoms of motion sickness regularly on journeys by road, sea or air.

According to the guide to motion sickness on NHS Choices, “Women are more likely to get motion sickness than men, particularly if they are pregnant or having their period. People who are affected by migraines may be more likely to experience motion sickness, and are also more likely to have a migraine at the same time as motion sickness. Motion sickness is also more common in children who are 3 to 12 years of age. After this age, most teenagers grow out of motion sickness.”

Symptoms

If you have travel sickness, you may have several symptoms, including:

  • feeling sick
  • vomiting
  • dizziness
  • a headache
  • sweating
  • looking pale
  • rapid breathing
  • drowsiness

Symptoms get better when the motion stops. They also tend to get better or go away completely on long trips, such as on a ship as you’re likely to adapt to the motion and gradually recover.

How is motion sickness treated?

According to MedicineNet, “Antihistamine medications are commonly used in the prevention and treatment of motion sickness. These medicines seem to prevent and treat the nausea, vomiting, and dizziness caused by motion sickness by calming the stimulation of the inner ear. Examples of antihistamines used for this purpose include meclizine (Bonine, Antivert, Dramamine). “

Bupa recommends Hyoscine hydrobromide (or referred as Hysocine commonly), which is one of the best medicines for preventing travel sickness. It works by blocking the confusing nerve signals from your vestibular system. You can buy tablets containing hyoscine over-the-counter at a pharmacy. It also available on prescription as a skin patch.

Complementary therapies such as acupressure and ginger are also found to have some positive effect.

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