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Nothing will ruin a road trip, boating adventure, train commute, or corkscrew ride faster than suddenly losing your lunch. Motion sickness occurs when your body's motion sensors — your eyes and inner ears — don't sync up, says Dr. Michael Zimring, director of the Center for Wilderness and Travel Medicine at Mercy Medical Center in Baltimore. "If you're bobbing up and down in a boat, your inner ear canals will tell the brain that your body is in motion," he explains. "But if you're staring at the seat in front of you, which stays fairly stationary, your eyes will tell your brain that you're not moving. When the brain receives opposite signals from different sensors, things don't jive and you get sick."

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Although there are drugs like Dramamine and other antihistamines that can help prevent motion sickness, they have a host of side effects, says Zimring, such as drowsiness, dry mouth, blurry vision, and constipation. Try these easy, drug-free tricks instead.

1. Don't pig out pre-trip.
It's good to have some food before leaving on a long trip, but don't eat a heavy, greasy, gut-bomb meal right before hopping in the car or boat. "The more junk you have sitting in your stomach, the more likely you are to feel sick and throw it all up," Zimring says. Instead, opt for a lighter, nutrient-dense meal, or eat a protein-rich snack like nuts or Greek yogurt to tide you over for a while.

2. Drink plenty of water.
"Hydration is so important for everything your body does, including helping to keep it all in sync" Zimring says. "That's why drinking enough water is the biggest thing I advise people to do before traveling. I'm not even sure exactly how being hydrated helps prevent motion sickness, but it doesn't matter — it definitely does."

3. Drive or ride shotgun whenever possible.
It's super rare to get motion sickness while driving a car because your eyes stay firmly focused ahead, which tells your brain you're cruising. But if you sit in the back seat, you'll be staring at the back of the driver's head rest, making you much more likely to feel ill. If you're not the captain of your next road trip, be sure to call shotgun so you can keep your eyes on the road and the scenery in front of you. "Always look off into the horizon, whether in a car or boat, and it's very unlikely you'll get sick," Zimring says.

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4. Keep your eyes open.
If you're one of those guys who can zonk out in the back seat of a car or on the train and not become queasy, congrats. But for many people, closing their eyes to try to catch a nap while riding is a surefire way to get sick. "Even when your eyes are shut, they're still sending the message that you're stationary while other sensors are telling the brain otherwise," Zimring says. "Closing your eyes can get you into trouble."

5. Don't read.
Here again, some people have no trouble tacking a novel while riding shotgun, whereas others can't even page through a magazine without getting nauseous. If you're prone to motion sickness, Zimring says reading is one of the worst things you can do. "Your eyes will be looking down, concentrating on a fixed point, and not realizing your body is moving," he says. If you're intent on reading to help wile away the time, try doing so in spurts. For instance, read for 10 minutes, and then put the book down and look straight ahead of you for a few minutes to recalibrate before picking it back up.

6. Take ginger before traveling.
Ginger root is a traditional treatment for nausea, and studies have shown it can help buck motion sickness as well. The easiest way to get it is via capsules of powdered ginger root, taken about 30 minutes before you set sail. Zimring says even candy made with real ginger can help, although it's likely not as effective as ginger root.

7. Try acupressure.
Pressing on the P6 acupressure point that sits about two inches up your arm from your wrist crease, right in the center, and holding it for a few minutes can help relieve nausea. Or try an acupressure wristband like Sea-Band, which fits on your wrist snugly and has a plastic stud that presses on the P6 point. Wristbands are cheap, reusable, and have no side effects.