Why it occurs and how you can prevent it

Motion sickness is a common ailment caused by exposure to certain types of motion. Such motion may be experienced during an amusement park ride, an ocean cruise, or a car ride on a winding road. Although individual susceptibility to motion sickness varies greatly, most people are susceptible if the motion is provocative enough.

The most common symptoms of motion sickness are nausea and vomiting. Other common symptoms include spatial disorientation, malaise, headache, drowsiness and dizziness. Such symptoms may begin minutes after experiencing the offending motion and may last for hours after the motion stops.

Causes of Motion Sickness
The principal cause of motion sickness is a conflict among the sensory signals that communicate the position and movement of the body to the brain. Specifically, the brain combines sensory information from the inner ears (the vestibular system), eyes, skin, joint positions, and its own expectations. Normally, all the sensory signals and the expectations are in agreement. However, when you are reading a book in the back seat of a car on a winding road, the inner ears and the skin receptors sense the car’s motion, but the eyes see only the stationary pages of the book. This sensory conflict can potentially trigger the usual symptoms of motion sickness.

Motion Experienced in a Car
The human body in a moving car moves along three independent axes: the vertical axis and two horizontal axes (front-to-back and side-to-side). The vertical motion (or oscillation) is caused by road bumps and potholes; the front-to-back motion is caused by acceleration and braking; and the side-to-side (lateral) motion is caused by turning a corner or by driving on a curvy road. The vertical motion does not provoke motion sickness because it is effectively damped by the vehicle’s suspension system. The motions along the two horizontal axes are also muted when the car is cruising steadily on a straight and empty freeway. But these horizontal motions can become significant during city driving. And they may become specially pronounced when the car is negotiating a winding road through the mountains.

Prevention
If you have a history of motion sickness when exposed to a specific type of motion, it is a good bet that you will get sick again. In general, prevention of motion sickness is far more effective than treatment of symptoms after they have occurred.

There are many practical strategies for preventing or minimizing motion sickness. An obvious strategy is to simply avoid activities that are known to be especially nauseogenic, e.g., a challenging amusement park ride or a small boat ride in rough water.

If avoidance of unpleasant motion is impractical, then try to reduce the intensity of the motion stimuli. In a public vehicle, choose a seat location that minimizes motion: near the wings in an airplane, near the waterline in the middle of a boat or ship, and near the front in a bus. In a private vehicle, ask the driver to accelerate and brake gently, and to slow down on the curves. Reducing the curve speed by 30% (say, from 35 mph to 25 mph) decreases the level of lateral acceleration by half.

Another key strategy is to minimize the potential sensory conflict arising from any motion. In a car, the best way to do so is to drive the car yourself. As a driver, you can anticipate any turn, acceleration, or braking, and prepare your brain and your senses for the expected motion stimuli. Indeed, car drivers rarely get motion sickness, especially if they drive gently and confidently.

But what if driving is not an option for you? In that case, the best alternative is to sit next to the driver and pretend that you are driving. Focus on the road ahead and anticipate all the bumps and turns the way the real driver is doing. Whenever the car turns, tilt your head (like the driver) towards the curve center. Memorize the routes you take frequently so that you can anticipate every turn and twist along the way. As we enter the brave new world of self-driving cars, “pretending to drive” could become a popular technique for preventing motion sickness.

Some other do’s and dont’s
Always sit facing forward. Look at the road ahead. Don’t read a book or look at a screen. If you start feeling queasy, take a short break and step out of the car. On a boat or a ship, stay on the deck and look forward at the horizon. Don’t watch or talk to another person who is having motion sickness. Alternatively, take a nap if you can (during sleep, the brain stops receiving the sensory signals). Don’t travel on an empty stomach or a very full stomach. And drink water to stay well hydrated.

Medications and Alternative Therapies
Medications are most effective when taken prophylactically, i.e., as a preventive. Most medications must be taken at least 30-60 minutes before travel begins. On long trips, extra medication may be needed during the trip. A prescription drug for preventing motion sickness is Scopolamine (hyoscine hydrobromide). It is available as a transdermal patch that must be placed behind the ear at least four hours before the trip. Some over the counter medications are Dramamine (dimenhydrinate) and Bonine (meclizine). Note, however, that all these drugs do have significant side effects.Among alternative therapies, ginger is a popular choice. Take some ginger root before the trip, and carry some ginger gum to chew on the trip. There is also some evidence that stimulation of the P6 acupressure point on the inner wrist (using manual pressure or a wrist band) is helpful.

Finally, all these drugs and therapies work better when used in conjunction with the behavioral prevention strategies described earlier.

Adaptation
A very different technique for preventing motion sickness is adaptation (or habituation). This technique is based on the observation that repeated exposure to a sensory stimulus makes one less sensitive to that stimulus. Adaptation to a motion stimulus is best illustrated by sailors returning from a long sea voyage—they get so used to the rocking motion of a ship that they suffer from so-called “disembarkation sickness” when they finally return to land. Closer to home, frequent bus travelers usually become desensitized to a bus’s motion, perhaps after going through a few unpleasant episodes of nausea.

Tolerance to motion stimuli can also be increased through a program of exercises that are designed to induce motion sickness in a controlled and escalating manner. Such exercise programs are used to train astronauts and fighter pilots who must endure some very nauseogenic motion in their jobs. However, since the training program itself is very nauseogenic, only the most motivated people manage to go through it.

Motion sickness can be a minor inconvenience or a major constraint on your travel plans, recreational activities, and even career choices, depending on your degree of susceptibility.

In my own case, I have been susceptible to motion sickness since my early childhood. Initially, through habituation, I got used to traveling by buses and taxis in India. However, upon arrival in the United States (where travel speeds are much greater), I rediscovered motion sickness on a ride through California highway Route 1. Subsequently, through trial and error, I found motion sickness prevention strategies that worked best for me. I drive the car (whenever possible), or pretend to do so. The only small problem is that I have to remember to stop the car to enjoy the beautiful scenery.

Vijay Gupta is a math and physics tutor for high school students. He enjoys studying and writing about health issues from a consumer’s perspective.

Motion sickness is a common ailment caused by exposure to certain types of motion. Such motion may be experienced during an amusement park ride, an ocean cruise, or a car ride on a winding road. Although individual susceptibility to motion sickness varies greatly, most people are susceptible if the motion is provocative enough.

The most common symptoms of motion sickness are nausea and vomiting. Other common symptoms include spatial disorientation, malaise, headache, drowsiness and dizziness. Such symptoms may begin minutes after experiencing the offending motion and may last for hours after the motion stops.

Causes of Motion Sickness
The principal cause of motion sickness is a conflict among the sensory signals that communicate the position and movement of the body to the brain. Specifically, the brain combines sensory information from the inner ears (the vestibular system), eyes, skin, joint positions, and its own expectations. Normally, all the sensory signals and the expectations are in agreement. However, when you are reading a book in the back seat of a car on a winding road, the inner ears and the skin receptors sense the car’s motion, but the eyes see only the stationary pages of the book. This sensory conflict can potentially trigger the usual symptoms of motion sickness.

Motion Experienced in a Car
The human body in a moving car moves along three independent axes: the vertical axis and two horizontal axes (front-to-back and side-to-side). The vertical motion (or oscillation) is caused by road bumps and potholes; the front-to-back motion is caused by acceleration and braking; and the side-to-side (lateral) motion is caused by turning a corner or by driving on a curvy road. The vertical motion does not provoke motion sickness because it is effectively damped by the vehicle’s suspension system. The motions along the two horizontal axes are also muted when the car is cruising steadily on a straight and empty freeway. But these horizontal motions can become significant during city driving. And they may become specially pronounced when the car is negotiating a winding road through the mountains.

Prevention
If you have a history of motion sickness when exposed to a specific type of motion, it is a good bet that you will get sick again. In general, prevention of motion sickness is far more effective than treatment of symptoms after they have occurred.

There are many practical strategies for preventing or minimizing motion sickness. An obvious strategy is to simply avoid activities that are known to be especially nauseogenic, e.g., a challenging amusement park ride or a small boat ride in rough water.

If avoidance of unpleasant motion is impractical, then try to reduce the intensity of the motion stimuli. In a public vehicle, choose a seat location that minimizes motion: near the wings in an airplane, near the waterline in the middle of a boat or ship, and near the front in a bus. In a private vehicle, ask the driver to accelerate and brake gently, and to slow down on the curves. Reducing the curve speed by 30% (say, from 35 mph to 25 mph) decreases the level of lateral acceleration by half.

Another key strategy is to minimize the potential sensory conflict arising from any motion. In a car, the best way to do so is to drive the car yourself. As a driver, you can anticipate any turn, acceleration, or braking, and prepare your brain and your senses for the expected motion stimuli. Indeed, car drivers rarely get motion sickness, especially if they drive gently and confidently.

But what if driving is not an option for you? In that case, the best alternative is to sit next to the driver and pretend that you are driving. Focus on the road ahead and anticipate all the bumps and turns the way the real driver is doing. Whenever the car turns, tilt your head (like the driver) towards the curve center. Memorize the routes you take frequently so that you can anticipate every turn and twist along the way. As we enter the brave new world of self-driving cars, “pretending to drive” could become a popular technique for preventing motion sickness.

Some other do’s and dont’s
Always sit facing forward. Look at the road ahead. Don’t read a book or look at a screen. If you start feeling queasy, take a short break and step out of the car. On a boat or a ship, stay on the deck and look forward at the horizon. Don’t watch or talk to another person who is having motion sickness. Alternatively, take a nap if you can (during sleep, the brain stops receiving the sensory signals). Don’t travel on an empty stomach or a very full stomach. And drink water to stay well hydrated.

Medications and Alternative Therapies
Medications are most effective when taken prophylactically, i.e., as a preventive. Most medications must be taken at least 30-60 minutes before travel begins. On long trips, extra medication may be needed during the trip. A prescription drug for preventing motion sickness is Scopolamine (hyoscine hydrobromide). It is available as a transdermal patch that must be placed behind the ear at least four hours before the trip. Some over the counter medications are Dramamine (dimenhydrinate) and Bonine (meclizine). Note, however, that all these drugs do have significant side effects.Among alternative therapies, ginger is a popular choice. Take some ginger root before the trip, and carry some ginger gum to chew on the trip. There is also some evidence that stimulation of the P6 acupressure point on the inner wrist (using manual pressure or a wrist band) is helpful.

Finally, all these drugs and therapies work better when used in conjunction with the behavioral prevention strategies described earlier.

Adaptation
A very different technique for preventing motion sickness is adaptation (or habituation). This technique is based on the observation that repeated exposure to a sensory stimulus makes one less sensitive to that stimulus. Adaptation to a motion stimulus is best illustrated by sailors returning from a long sea voyage—they get so used to the rocking motion of a ship that they suffer from so-called “disembarkation sickness” when they finally return to land. Closer to home, frequent bus travelers usually become desensitized to a bus’s motion, perhaps after going through a few unpleasant episodes of nausea.

Tolerance to motion stimuli can also be increased through a program of exercises that are designed to induce motion sickness in a controlled and escalating manner. Such exercise programs are used to train astronauts and fighter pilots who must endure some very nauseogenic motion in their jobs. However, since the training program itself is very nauseogenic, only the most motivated people manage to go through it.

Motion sickness can be a minor inconvenience or a major constraint on your travel plans, recreational activities, and even career choices, depending on your degree of susceptibility.

In my own case, I have been susceptible to motion sickness since my early childhood. Initially, through habituation, I got used to traveling by buses and taxis in India. However, upon arrival in the United States (where travel speeds are much greater), I rediscovered motion sickness on a ride through California highway Route 1. Subsequently, through trial and error, I found motion sickness prevention strategies that worked best for me. I drive the car (whenever possible), or pretend to do so. The only small problem is that I have to remember to stop the car to enjoy the beautiful scenery.

Vijay Gupta is a math and physics tutor for high school students. He enjoys studying and writing about health issues from a consumer’s perspective.

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