Eyes versus ears

Scientists aren’t positive what causes seasickness but suspect the culprit is confusing signals to the brain from your inner ear and your eyes. When we move our bodies, changes caused in our inner ears match what we see. The brain processes both inputs and concludes that you are, in fact, moving. But step into, say, an airplane, and your inner ear picks up the motion of the vessel, but your eyes see a stable environment — the aircraft around you isn’t moving — and tells the brain, nope, we’re sitting still. Cue the vomiting.

Locke studies motion sickness using a spinning chair, with about 70 percent of his subjects succumbing. That may mean the other 30 percent are naturally immune to motion sickness, except in severe conditions (he doesn’t get too carried away). But it doesn’t necessarily translate outside his lab; the chair goes through the exact same motions each time, while motion varies dramatically in the real world. Individuals vary, too.

Naval aviator Lieutenant Ben Walborn has more than five years of flying a variety of aircraft under his belt and currently trains new pilots. No one would call this guy a wimp, yet he freely admits to puking in planes more than a few times. He deals with the motion sickness by acclimating.

“You just have to go up and stay busy and keep your mind on the task.” He also admits that it “messes with your ego” to get sick around all those Type A personality naval aviators. Walborn has seen flight students who don’t get sick no matter what, as well as the severely incapacitated, and others who “puke and rally.” He’s one of those.

Getting your sea legs

Walborn’s experience proves your body can adjust. In fact, Catherine Webb, a research psychologist at the US Army Aeromedical Research Laboratory, says adaptation is one of the best ways to deal with motion sickness.

“Reports state that about 95 percent of the population will eventually adapt to a motion environment,” she says. But adaptation takes time, probably more than you’ll have on that sailing excursion, bus tour through the mountains, or flight. And the more variable the conditions, the harder it is to adjust. Plus, adaptation must be maintained.

“If you don’t fly for a month, or you change [type of] airplanes,” says Walborn, “you have to deal with it again.” Not good news for those who board boats or planes only occasionally.

Captain Edwin Y. Park, a neurologist at the Naval Aerospace Medical Institute in Pensacola, FL, believes factors such as anxiety affect a person’s susceptibility. Walborn agrees. “If you think it’s going to happen, it’s going to happen,” he says. “Once you get comfortable with the airplane and know what to expect, your anxiety goes down.”

Locke is less convinced, based on his chair experiments. No matter how people feel before the test, he says, that sick feeling hits them at almost exactly the same point every time. He also hasn’t seen significant difference between uber-conditioned astronauts and geeky researchers riding in NASA’s DC9 aircraft, used to create brief periods of zero gravity — a.k.a. the Vomit Comet. That could explain how you may see the biggest macho guy on the boat hanging over the rail next to Grandma.

Walborn tried the usual alternative remedies — ginger, wrist bands, pressure points — to no avail, and no wonder, as Locke says studies have yet to provide clear evidence that any of them work. If one seems to do the trick for you, he says you’re most likely immune to motion sickness, or else the type and severity of motion that time simply didn’t reach your trigger point.

It does help to look at horizon, and to lie on your back, as the inner ear seems less sensitive to motion in that position. Fresh air alleviates symptoms such as feeling hot and sweaty, but not the nausea, Locke says. He sees no difference in the Vomit Comet when it’s hot or cold, either.

Scop and other drugs

Studies have shown that antihistamines, anticholinergics, amphetamines and serotonin agents are effective in treating motion sickness. Locke reduced incidence of motion sickness in the Vomit Comet from 70 to about 12 percent using anticholinergic scopolamine combined with dextroamphetamine. He uses oral or injected scopolamine, which takes effect quickly and can be given in higher dosage. But it isn’t readily available in those forms to the general public; we get patches, which need hours to take effect and may not deliver enough dose to handle much motion. Over-the-counter medications tend to work only with fairly mild motion as well.

Worse, motion sickness drugs usually make you drowsy or impaired. Scopolamine can cause drowsiness (hence Locke’s dextroamphetamine cocktail), dry mouth and impaired vision, which takes your vacation experience down a notch. It effectiveness decreases and side effects increase with repeated use. Side effects also increase with age. Locke says elderly people can even become psychotic when taking it — not what you want to run into in the cruise ship casino. It can also cause stupor, which has implicated it in South American zombie rumors.

Clearly, the proper medication, dosage, and timing are key, but your typical physician doesn’t always know those. “So far,” Locke says, “there’s no magic bullet.” Until there is, plan your trip with time to acclimate, resign yourself to the “puke and rally” approach, or slap on a patch and bear with the side effects.