How Seasickness Works

By: Charles W. Bryant
While not as likely, you can even get seasick on a huge ship like the QEII.
Chris Jackson/Getty Images

food, drink and fun. You can dance, gamble, take a class, see a show, canoodle, admire ice sculptures, watch movies, swim, exercise and eat and drink your fill every day. This is the sunny side of cruising, and if you're into it, you aren't alone. Cruise Lines International Association projects that 34 million adults over 25 years old will go on a cruise in the next three years [source: Cruise Lines International Association]. But there's a dark side to your Love Boat experience.

There aren't any definitive statistics to indicate what percentage of cruise ship passengers get seasick, but it's believed to be pretty low for a few reasons. For one, cruise ships are huge. A standard cruise ship these days is roughly 1,000 feet (304 meters) long and 100 feet (30.4 meters) wide. They weigh more than 70,000 tons (63,500 metric tons) and can carry close to 3,000 passengers on board. They also extend as far as 30 feet (9 meters) below sea level. In the ocean, a large vessel is more stable against the rocking and rolling of the sea. Cruise ships also have stabilizers built into their structure that keep them as steady as possible. But even cruise ships aren't immune to exceptionally rough seas.


­You're more likely to get seasick on a smaller vessel. So if you have a day of deep-sea fishing planned on a chartered boat, prepare to feel some ill effects. Seasickness is a form of motion sic­kness. It's triggered when parts of your body that detect motion, like your eyes and inner ear, send unexpected or conflicting messages to the brain. Another way to say it is that it's a reaction to real, perceived or anticipated motion. We'll get into how this occurs in more detail later. Motion sickness isn't strictly for boat travelers. You can get motion sickness in a car, on a plane or on a roller coaster. You can also experience it watching a movie with shaky camera work, looking through a microscope or playing a video game. Pilots can experience it in flight simulators.

Seasickness is most prevalent in children ages two to 12, women and the elderly. If you have migraine headaches, you're also more likely to suffer from it, although it's unclear exactly why. Even though the percentage of cruisers that get seasick is low, imagine the worst-case scenario -- you're rendered incapacitated and left hugging your cabin toilet the entire voyage. Over the next few pages, we'll look into the science behind seasickness and what you can do to prevent it and deal with it when you can't avoid it.


What does it mean to be seasick?

Inner ear
The inner ear Images

Seasickness, or motion sickness in general, has to do with how your brain perceives movement. It usually means that the brain gets conflicting messages about the body's motion or position. For instance, if you're in an interior cabin of a ship without a window, your balance-sensing (vestibular) system will feel the motion of the boat without being able to see that you're moving up and down.

The vestibular system allows us to stand upright, maintain balance and move around without falling over. It organizes the information sent from the eyes and inner ear and sends it to the central nervous system by way of a cranial nerve. When this information contradicts your body's prior experience, you get motion sickness. Take the interior cabin example. Your brain has no prior experience with feeling a severe up and down bobbing movement without being able to verify it with a look out the window. This confuses the brain and you get motion sickness. If you've never been on a boat at all, then you have no prior experience, so you may be in trouble with or without a window.


The inner ear plays a big part in the vestibular system. The outer portion of the inner ear is called the cochlea. It basically functions as a loudspeaker. It converts sound pressure impulses from the outer ear into electrical impulses and passes them on to the brain via the auditory nerve. Further inside the ear are the semicircular canals. These are the body's balance organs. They use hair cells to detect movements of the fluid within the canals. The canals are connected to auditory nerves that send these signals to the brain. If you bend over to tie your shoe, the fluid in your semicircular canal sloshes around and tells the brain, "I'm bent over now, so don't get dizzy."

Stress can also play a part in motion sickness. If you've had a bad experience with it before, you can bring on the condition through mere anticipation. Some people who regularly experience motion sickness from cars, planes and boats can induce it just by looking at the offending mode of transport.

Feeling the up and down and side-to-side motion of a boat or ship doesn't mean that you're seasick. If you feel great, then it means you have your "sea legs." If you get seasick, you'll experience some or all of the following symptoms:

  • Fatigue
  • Dizziness
  • Nausea
  • Sweating
  • Headache
  • Vomiting

How do you fight seasickness? Find out on the following page.


Seasickness Prevention and Home Remedies

The windowless interior cabin of a cruise ship can lead to seasickness.
Rob Melnychuk/Getty Images

Your best bet for combating seasickness is to try and prevent it before it ever happens. Once it's started, it's more difficult to stop. If you have a history of motion sickness, you may want to avoid the smaller boats altogether. If you insist on going on a cruise, then book a cabin that's as close to the center of the ship as possible. This means up and down as well as back and forth. So if you're on a ship that has 12 decks, book a room on deck six or seven as close to the middle of the boat as you can. You'll be battling it out with other passengers worried about being seasick, so book early.

If you feel yourself getting nauseous, try stepping outside and focusing on the horizon. This can help orient the vestibular system. If you're in an interior room, you can try closing your eyes and lying down. Keep your head as still as possible. The symptoms may simply pass. Things like stuffy rooms and foul smelling odors can contribute to the nausea factor, so keep your room well-ventilated. Since stress can also play a part, try to stay calm if you feel symptoms rearing their ugly heads. Stay occupied by talking with cruise mates, but never read to take your mind off things. Reading can make your symptoms worse.


­Diet also plays a part. Avoid loading up at the buffet table. Small frequent meals are more likely to help you avoid getting sick. Stay away from refined breads, pastas and sugar, and stick with as many anti-oxidant filled fruits and vegetables as possible. Reduce the amount of red meat you consume in favor of lean fish and shellfish, which is never a problem aboard a cruise ship.

­Just like with your general nutrition, drink as much water as you can each day, at least six to eight 12-ounce glasses. There are a few herbs that cruisers are quick to recommend for a seasick-free experience. Ginger tablets, peppermint and milk thistle are all believed to help prevent and relieve seasickness. Some people swear by eating green apples.

One practical way to avoid seasickness is to choose to cruise in calm waters. The Gulf of Mexico and the waters of the Caribbean are notoriously calm compared to those of the Pacific Ocean. So booking a three-week cruise from Southern California to Alaska may not be a good idea if you're prone to motion sickness.


Seasickness Medication and Alternative Methods

Make sure you eat plenty of ginger on your three-hour tour -- it's a natural remedy that can help with seasickness.
Simon Battensby/Getty Images

An ounce of prevention may be worth a pound of cure, but if you're vomiting into a cruise ship toilet then that pound of cure is worth something too. Enter medications. A ship's doctor can help you out with any kind of medication you need. But if you know you're prone to motion sickness, then do yourself a favor and bring some of these meds along with you. There isn't one single cure-all for seasickness, so you'll have to experiment until you find something that works for you.

­There are two ways to go with seasickness medications. Some work only on the nausea, while others try and minimize the motion effect. Scopolamine is the most popular drug for motion sickness and is only available by prescription. It blocks the vestibular organs from sending messages to the central nervous system. It can be delivered orally, by injection or as a transdermal patch you wear on your skin. The patch lasts about three days. You'll need to take scopolamine before you feel symptoms, and side effects include dry mouth, nose and throat, blurred vision and drowsiness.


Antihistamines are another alternative. They work by depressing the vomit center of the brain. They're available as over-the-counter (OTC) or prescription-only and include:

  • Promethazine (Phenergan, Prorex, Anergan 50) -- This prescription-only decreases nausea, but is the most sedating.
  • Dimenhydrinate (Dramamine, Triptone, Gravol) -- You need to take this OTC every four to eight hours.
  • Meclizine (Bonine and Dramamine II) -- This OTC has a once-a-day dosage and is less sedating.
  • Cyclizine (Marezine) -- The dosage for this OTC is required every four to six hours.
  • Diphenhydramine (Benadryl) -- This OTC causes significant drowsiness.

Antihistamines all make you somewhat drowsy and impair your motor skills. The effect is increased with alcohol, so you shouldn't hit a booze cruise if you plan on taking these drugs.

There are also acupressure bracelets you can wear to help relieve nausea, but their effectiveness is subject to debate. The bracelet, or band, applies pressure to the palm side of your wrist to an acupuncture point called pericardium 6, or P6. The bands are also used by chemotherapy patients and pregnant women. Since no drug is administered, it's the safest way to go if it works, and it allows you to indulge in a guilt-free cocktail or two.

Habituation is another treatment used by those who suffer from motion sickness. It involves exposing yourself to the trigger that causes motion sickness -- in this case, going out on a boat -- until you become used to it. The theory is that over time the repetitive exposure to the stimuli will help to decrease the response, or the sickness. Balance training through yoga and meditation are a couple of other alternative therapies you can try. One cruiser from a Web forum suggests focusing the meditation on the comforting feelings that a baby gets from rocking back and forth. Since it's very unusual for a child under two years old to suffer from motion sickness, there may be something to this therapy. If you're set on cruising or boating and have a tendency to get motion sickness, try every tip and trick you can and experiment with a variety of preventative medications to find one that works. The high seas await you.


Lots More Information

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More Great Links

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