by Rupa Mukherjee, MD
As a doctor specializing in stomach disorders, I commonly see patients who suffer from nausea stemming from a variety of causes. During the summer months, when fishermen and boaters spend more time on the water, I hear more complaints about nausea from motion sickness than I do any other season.
People may experience motion sickness from being on small or large boats, in cars or airplanes, and even on amusement park rides. It can be experienced in other environments when you might least expect it as well, from virtual reality games to driverless cars.
Motion sickness is very common, impacting up to 70 percent of people, based on various conditions. Key symptoms include nausea, dizziness, and fatigue, but people may also experience cold sweats, increased salivation, and pain. Luckily, none of these side effects last forever and most dissipate once on land.
Motion sickness can affect anyone. Even animals experience it. The Antarctic explorer Ernest Shackleton brought ponies on his expeditions and recorded in his diaries that they suffered during storms. Cats, monkeys, birds, and sheep experience seasickness as well. There is even an FDA-approved drug for motion sickness for dogs.
There are two main theories about why motion sickness occurs. The most commonly held theory has to do with sensory conflict. The human body has a system of sensing balance that involves communication between various organ systems. These include your eyes for vision; your skin and muscles (collectively known as “touch” or “proprioception”); and the inner ear and vestibular system, which have numerous small bones and canals that manage balance. Some believe that the neck and ankles play a particularly important role in balance and motion sickness. Your brain takes in all of this information from the various organ systems and tries to make sense of it in an effort to maintain balance.
The acupressure-inspired Sea-Band has a plastic bead that presses against a pressure point located on the palm side of the wrist that is said to reduce nausea. It is available without a prescription and has no side effects.
Antihistamines can be effective in curbing motion sickness. Dimenhydrinate (known as Dramamine), meclizine (known as Bonine) and diphenhydramine (known as Benadryl) are available over the counter but are known to cause drowsiness, dry mouth and other side effects.
The Transderm Scop patch requires a prescription and works by blocking brain signals that cause queasiness. The patch is placed behind the ear, where it slowly releases medication into the blood. This slow release helps minimize side effects such as drowsiness.
Ginger has been proven to help reduce nausea and is available in lozenge, candy, and gum forms. The Anchor Nutrition Bar combines ginger with protein and vitamin B6, which have also been shown to help reduce nausea.
The sensory conflict theory holds that when the sensory and vision systems, which tell your brain that you are moving in a certain direction, conflict with the inner ear/vestibular system, you will experience motion sickness. This can happen when you’re in a boat below deck and your body senses motion but your eyes do not. It can also happen if you put on 3D virtual reality goggles— your eyes see movement but your inner ear does not sense it.
Thomas Stoffregen, a professor of psychology at the University of Minnesota, holds another view, as was described in Scientific American several years ago. He believes that motion sickness is due to the brain’s failure to control body movements in a constantly shifting or unbalanced environment. He has shown that subjects in experiments can reduce motion sickness by increasing the distance between their feet— which connects back to the ankle point above. Subjects who kept a distance of only five centimeters experience motion sickness 60 percent of the time, but if subjects increased that space to 30 centimeters to stabilize the body, the chance of motion sickness reduced to about 20 percent. Stroffregen uses this evidence to show that the conflict between the sensory system and the vestibular system, as described above, is not the cause of motion sickness.
We don’t really know why motion, or the mismatch between the inner ear and sensory system, results in nausea. What we do know is that there is consistent interaction between the brain, nervous system, and stomach. For example, when you see a tasty slab of tuna on the grill, your mouth starts salivating and your stomach begins releasing gastric acid. We also know that the stomach has a rhythm, just as your heart does. The normal rhythm is three cycles per minute. (Doctors can measure this activity electrically by putting nodes on the stomach.) During periods of nausea, that activity might increase to four, five, or even ten cycles per minute. When your stomach is cycling that quickly, it makes you feel nauseous—like you want to chum.
While this might sound pretty unpleasant, thankfully, there are solutions and interventions that can help reduce the development of this increased rhythmic activity or at least help reduce it once it’s started.
Avoid an empty stomach
Numerous studies have shown that consuming food reduces nausea. This is true for nausea from motion sickness, morning sickness during pregnancy, or from medications. Studies have also shown that protein is more effective than fats or carbohydrates in preventing, alleviating, or delaying the onset of nausea. Ginger has been shown to help reduce nausea, and certain B vitamins, especially B6, have been shown to prevent nausea in certain cases.
Focus on the horizon
This strategy may work because you are bringing your visual perception back in line with your vestibular system’s sense of balance. The horizon moves, as does your body.
Widen your stance
As suggested by Professor Stoffregen, widening your stance can help improve your stability and may help reduce your motion sickness. Try drug remedies You can try over-the-counter or prescription drug remedies, but be aware of side effects such as drowsiness and sedation. Medication also might take some time to kick in, so plan to take them in advance of a motion sickness scenario.
Rupa Mukherjee, MD, a gastroenterology specialist, received her MD from Johns Hopkins, completed her residency at Yale, finished her GI training at Columbia and Harvard, and currently practices in Boston. She is medical advisor at Real Food Solutions LLC, maker of Anchor Nutrition Bar.