The fishing boat wallows in ocean swells. The station wagon lurches around another mountain curve. The commuter airplane bounces through a turbulent sky.
And you start to feel a little queasy. Why?
The problem is tied to your inner ears, or labyrinth, says the American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS). Your inner ears contain a delicate mechanism that senses your head's position. One of the main functions of this mechanism, besides helping you keep your balance, is to allow your eyes to adjust to head movements.
Imagine you're jogging along a bumpy road. Your head bobs up and down, moves all over the place. But still you can focus on objects along the road. Your inner ears give your eyes a warning a fraction of a second before your head moves, and your eyes adjust accordingly. The visual image stays focused.
When you're moving under your own power, your inner ears are well suited to make the proper adjustments. But all that changes when you enter cars, boats, planes, or an amusement park ride. When you're pitching around in ocean swells, your eyes are creating one set of sensory clues while your inner ears and body are creating another. Or, if you are reading in a car that's moving, your eyes see only the book, but your inner ears and body note that you are moving. These conflicting reports confuse your central nervous system, and the result is motion sickness.
Once you adapt to a new form of motion, the sickness often begins to go away. Sailors call learning to balance yourself on a moving ship "getting your sea legs."
Ironically, motion sickness can affect you even when you're not moving. The new high-tech amusements called "virtual reality" can create a sense of motion while you're sitting still. You can get just as nauseated as on a boat, experts say.
Why does this sensory conflict produce nausea? There are lots of theories, but no one knows for sure.
If you suffer from motion sickness, you can get better at handling it. Here are some tips from the AAO-HNS for helping avoid motion sickness:
Don't read in a moving vehicle.
Don't sit facing backward in a moving vehicle.
Avoid strong odors and spicy or greasy foods before and during traveling.
Several over-the-counter medications, including Dramamine and Bonine, are available to reduce motion sickness. Another medication, scopolamine, is absorbed through a patch that sticks to your skin, but is available only by prescription.