Discuss as:

Adult-onset motion sickness rare -- but can happen

Barf bags: They’re not just for kids anymore.

Chip Somodevilla / Getty Images file

Are we there YET? Adults are often unpleasantly surprised to discover they can develop the queasy stomach, cold sweats, dizziness and headaches of carsickness, even if they never had it as a kid.

In fact, they never were. When we think of motion sickness, the picture that most often comes to mind may be that three-hour car trip to Grandma’s with a heaving child and no change of clothing.

Yet some adults are unpleasantly surprised to find themselves coming down with the unforgettably bad symptoms of queasy stomach, cold sweats, dizziness and headaches, even if they never got them as kids. From vision changes to pregnancy, a number of triggers can upset our finely tuned internal balance system and set sickness in motion, so to speak.

Here how it works: Humans use our eyes, ears and feet to estimate of our location and movement through space. You get a conflict when the signals disagree, which can happen to any of us if the conditions are bad enough.

“Let’s say your eyes are reading in the car, so they think you should be still, but the bouncing of the car tells your ears you’re moving,” says Timothy Hain, M.D., an otoneurologist and professor at Northwestern University Medical School.

Kids may be more prone to motion sickness simply because their ears work better; as we age we lose inner ear function, along with the tendency to hurl on a swaying boat.

Yet other hazards await adults. One often overlooked cause of persistent motion sickness may be a visual disorder -- also known as  “see-sick syndrome,” says Dan Fortenbacher, O.D., who treats the disorder at his practice in St. Joseph, MI. In these cases, an eye problem such as decreased depth perception or muscle control sends miscues to our vestibular system, a part of the inner ear and brain responsible for keeping us in balance as we go about our lives.

In many cases, patients have had vision issues since childhood, but age-related changes make it harder to compensate, Fortenbacher says.  It doesn’t take a car trip to set things off; patients may feel sick watching a movie, scanning the aisles while grocery shopping, even looking at stripes on a shirt.

“Sea sickness wasn’t an issue. My problem was being vertical. I would stand up and have to hold on because I would feel like the room was moving,” says LaReine Gretzky of Bridgman, Mich.

A stroke or bump to the head can also disturb the balance system. For Norman Greene, a television executive producer from New York, a head injury from a bad taxi accident at age 36 led to later miseries in any moving vehicle, particularly the helicopters he flies in to film.

“I discovered this when I took this little, baby roller coaster with my kid at Sesame Place. I had to sit down; I was horribly sick. I felt like I’d been tossed into a burlap bag and thrown off a bridge,” he says.

Inner ear problems like an infection or a circulatory problem can also affect the vestibular system. Seems reasonable, but experts are still puzzled as to why pregnancy and menstruation make women more prone to motion sickness.

Another double-whammy:  Migraine sufferers, who are more sensitive generally to external stimuli, are also about five times more likely to also suffer from motion sickness, Hain says. Peak ages for both maladies are parallel in females: Girls usually start getting migraines around age 12, when puberty kicks in.  There is another peak at age 35, then a second peak at age 52, around the time of menopause.

Treatment for see-sick syndrome involves eye exercises and special lenses.  For the rest of us, avoiding bumpy seats, a pre-trip heavy meal and reading can ward off the occasional travel queasiness.  And if you can, drive.

“Drivers have a big advantage in avoiding motion sickness.  Because they know where they are going, there are fewer surprise motions,” Hain says.

Do you suffer from motion sickness now -- even though you never did as a child? We'd love to hear from you. Leave a comment here or on Facebook; we may use your story in an upcoming msnbc.com post.