Passengers on boats or in cars on curvy roads often feel the symptoms of motion sickness. It happens because we physically sense motion with both our ears and our eyes. When a boat bobs on the water or a car swoops from one hairpin turn to the next, the two signals can conflict, causing motion sickness.
The symptoms of motion sickness can be severe—debilitating nausea, vomiting, headaches, and a general feeling of misery. Fortunately, all that's necessary is to stop the movement, and the symptoms will quickly recede.
You are less apt to experience motion sickness if you are the one who is driving the car. As a passenger, you can sometimes lessen the effect by focusing your eyes on the horizon straight ahead of you.
If you are prone to motion sickness, your doctor can prescribe medication to take before you get into the car or the boat. Although these drugs are successful at banishing the symptoms, both children and adults who take them become sleepy. Falling asleep on a long car ride is a good thing for children who tend to suffer from motion sickness. But if you are driving or operating equipment, or you need to be alert for any reason, it is better to avoid them.