The following essay is reprinted with permission 
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My first experience with motion sickness was in college, standing behind a marine research vessel looking at something interesting dredged up from the ocean floor off the coast of California. It was a day trip, but the weather was fine and the sea was calm. I didn’t notice the boat’s gentle pitch and roll, instead focusing on the mud and creatures on the table in front of me.
Then my body slowly warmed up and I began to salivate. I felt tired even though I had enough rest. I had severe waves of nausea and started vomiting. It was a long afternoon. When I got back to shore, I felt like I was still moving. I didn’t feel normal again until the next day.
In retrospect, this was the perfect situation for motion sickness. I was focused on the environment in front of me, a table covered with visually stable sea specimens. My eyes weren’t aware that we were actually moving up and down and side to side with the waves. But my inner ear was signaling all of this movement to my brain. Sensory signals from the muscles and joints of my body provided information that resembled visual input from the eyes multiplied by balance feedback from motion detectors in the inner ear.
In short, my feelings were contradictory. I found myself in a situation that conflicted with my lifelong expectations about how sensory information usually combines to give me information about the world. My brain realized something was wrong and tried to save me from what it was designed to deal with: addiction and other illnesses. To my brain, emptying my stomach and forcing myself to rest and recover seemed like the perfect solution.
For me, this event preceded a lifelong study of the vestibular system, the structure and function of the inner ear and brain that keeps us oriented and stable in space. In my lab, my colleagues and I have replicated this type of complex movement and conflicting sensory input, and how the brain uses them during development, normal adult behavior, and in disease. Researching. Ultimately, we hope to develop treatments for people disabled by the loss or disruption of these sensations.
A Mismatch Between Amazing Systems and Abnormal Situations
Any moving environment can cause motion sickness. It is usually not caused by an illness or pathology. Rather, motion sickness is the result of optimal functioning of your nervous system based on what you have learned throughout your life.
As it processes sensory information and generates motor commands, the brain constantly monitors and coordinates its inputs and outputs to efficiently perform life tasks. For example, to see clearly while rotating the head, the brain moves the eyes in the opposite direction of the head movement and makes the same movement. It does this based on feedback from sensors in the inner ear that emphasize balance. The brain constantly monitors this reflex and continuously makes adjustments to ensure that the eye and head movements are perfectly aligned.
The efficiency of this system is based on experience and results, and it works well. It helps to coordinate movements and maintain balance during adolescence, and later in life to help recover from imbalance and disorientation caused by injury, illness, and aging.
The downside to this process is that the nervous system is unprepared for the unexperienced. This explains why astronauts experience temporary nausea as they adjust to weightlessness, why sailors get seasick, and why watching movies on an iPad in the back seat of a car or playing an immersive virtual reality video game Partially explains why playing Humans did not evolve as a species to do these things.
In other words, people with motion sickness are performing well-optimized functions in a uniquely challenging and sub-optimal environment.
lifelong change
Infants and young children usually do not experience motion sickness. Older children are much more prone to motion sickness as they learn the typical relationships between different senses.
As we age further into adulthood, susceptibility to motion sickness usually decreases again, presumably because we are able to contextualize the experience. In older people, motion sickness can increase or decrease due to changes such as loss of ear and eye receptor cells, clouding of the lens of the eye, and loss of peripheral nerve function. However, the incidence of motion sickness in generally healthy older adults continues to decline.
A simple example of this is that my balance is actually better than my grandma’s as a toddler. Her inner ear balance her system and muscles are brand new. mine is not. In fact, I lost many of the motion-sensing ear receptors due to normal aging. However, I have learned to use my sensory and motor complements to my advantage, and over the years have continued to adapt to the ever-changing new normal. She is just beginning this learning process.
Techniques for coping with motion sickness
If you experience motion sickness, there are several remedies you can use to make yourself feel better.
The first is resolving the conflicting sensory information produced by the situation. See a stable reference on Earth. For example, focus on the shore or horizon if you’re on a boat, or move to the front seat of your car and look out the window. In this way, it coordinates the incoming visual information with the inner ear vestibular information.
A second strategy is to reduce the information that is causing the conflict. Some drugs work by suppressing vestibular information in the inner ear, and others change how sensory information is processed in centers in the brain.
You can also suppress this conflict from being printed. Essentially, by short-circuiting the mechanism that produces the motor response of vomiting, you can thwart your central nervous system’s attempts to rescue yourself from the situation. Taking anti-nausea medications reduces nausea, not necessarily resolving the sensory conflict that caused nausea.
Repeated experience will eventually allow you to adapt to many new situations. As the brain learns the new normal, it can function in challenging environments with fewer unwanted symptoms. For example, NASA is developing preconditioning measures to help astronauts transition from Earth’s gravity to zero-gravity space more quickly and with fewer symptoms of motion sickness.
Such research will expand the range of environments in which humans can function, allowing us to explore, and ultimately inhabit, novel and new worlds.
This article originally appeared in The Conversation. Please read the original article.
