Hakai Magazine

Coastal science and societies

seasick passengers on ship
Seasickness has likely been around for as long as humans have sailed the seas. Photo by Egill Bjarnason

The Rolling, Lurching, Vomit-Inducing Road to a Seasickness Cure

Searching for a solution has its ups and downs.

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Text and images by Egill Bjarnason

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The worst thing about being seasick is knowing you are not going to die.

Another fun fact: don’t tell this joke to the seasick. They will not laugh. I learn this onboard a whale watching vessel in Iceland’s Eyja Fjord, some 60 kilometers from the Arctic Circle. The ticket office had presented the tour with pictures of happy passengers, mouths wide open in amazement, watching a whale lift its fluke above the calm ocean surface. This tour is different. I watch waves, fog, and a good half of the passengers regretting every minute on board in nine different languages and one shared reaction—puking.

Back on land, skipper Aðalgeir Bjarnason rushes to clean the ship’s sides and deck before the next load of passengers arrives. He hoses off random puddles of vomit, concentrated at the midship and stern, exhibiting the ingredients of a nearby soup-of-the-day offer. “Corn,” he murmurs over some hard-to-get yellow pieces sticking to the boat like barnacles. “It seems like people don’t digest it properly?”

That is all he has to say about seasickness, a condition so miserable it reduces a person’s will to live, even on a sinking ship, and makes millions of people hesitant to travel on boats. Desperate sailors have, over the centuries, tried amphetamines and acupressure, ginger and green apples, and other tricks that may defeat the nausea but never fully bring the body back to normal.

Like fully digesting corn, human evolution seems to be simply out of luck when it comes to adapting to seasickness.

The only way to prevent seasickness is to avoid ships altogether, which is relatively easy. But emerging technologies may make it more difficult to escape other forms of motion sickness. Riding in driverless cars, for instance, causes increased rates of motion sickness, especially if a passenger is multitasking. Megaskyscrapers have given rise—pun intended—to a phenomenon called high-rise motion sickness. And virtual reality has a motion sickness problem called cybersickness.

The emerging problems are reviving an old field of research with a wave of grant money. Akureyri, the town nestled at the bottom of the long Eyja Fjord, is the largest community in northern Iceland and a tourism hub where whale watching is a top activity. It’s also where about 80 researchers have arrived from 15 countries, gathering for the first-ever International Congress on Motion Sickness. They are eager to solve a problem that has haunted humans since the days of traveling in boats (seasickness), on carts (cartsickness), by palanquins or litters (littersickness), and on camels (camelsickness).

Outside the harborside conference center, the whale watching ships sail by with passengers probably enacting the stubborn motion problem that’s under discussion inside the venue.


Humans have been crossing seas for at least the past 65,000 years, so it seems about time experts from around the world gather to discuss a potential solution to what’s been an intractable predicament. Despite thousands of years of breakthroughs in maritime problems—treating scurvy, for one—the fundamental understanding of seasickness is unchanged, with ancient accidental sailors likely learning the hard truth on their drifting rafts: some people suffer badly, others less so. But everyone can suffer, and solutions are elusive.

With intense-enough motion, almost anyone can be pushed toward the range of symptoms known as seasickness: increased salivation, stomach awareness (gastric feedback to the brain that says something funny is going on), vomiting, cold sweats, burping, more vomiting, yawning, increased sensitivity to odors, and more. What is happening—besides rough seas and shitty weather—is generally accepted by science as the brain reacting to sensory conflict. Before seasickness was linked to the brain, it was assumed that the human body was packaged with a sort of “do not shake” instruction. Thus, “sailing on the sea proves that motion disorders the body,” wrote the ancient Greek physician Hippocrates around 400 BCE. Then, some 23 centuries later, scientists identified the vestibular system located in the inner ear as responsible for the sensations of balance and motion.

Your body has three tools that work together to keep track of its position: vision, proprioceptive feedback (muscles, skin, and joints), and the vestibular system in your inner ears. Your eyes and muscles respond to the immediate environment. Your muscles, skin, and joints, meanwhile, keep track of what you’re feeling as you move along. Your inner ears detect circular and linear motion, and they cross-check with each other to tell you where up and down are and how you’re moving, plus they stabilize your vision.

The rising and falling motion of a ship, however, changes the cues. Your inner ear moves up and down and side to side with the waves. But your eyes and muscles are reacting to your cabin, which they perceive as stable. Wave after wave is logged in your brain as something like: !?!?!?!☠. According to an old saying, there are three types of people: the living, the dead, and the seasick.

On day one of the conference in Akureyri, it becomes clear to me that the neglected research field of motion sickness is dominated by two types of scientist: the old and the young. The old—usually from a medical background—began their careers studying military pilots and astronauts back when governments sought, by all means possible, to put humans in superfast fighter jets and spacecrafts. The young—the tech savvy, with significantly nicer PowerPoint slides—have published the early results on cybersickness, driverless cars, skyscrapers, and high-intensity sports.

Motion sickness, as many point out, is not a sickness or a disorder by definition. Clinically, it’s “a natural response to unnatural conditions.” There is a point where it’s no longer “natural” and becomes an actual illness: if you can’t adapt, even after many exposures, and you feel sick for a long time after motion ceases, it’s a problem and an illness. However, unlike a fear of heights, and maybe even hiccups, the motion sickness reaction has no practical meaning. Evidence suggests it’s really just one big misunderstanding.

“The best explanation is that motion sickness is a bit like other sicknesses: to clear out poison,” says John Golding, a professor of applied psychology at the University of Westminster, England, presenting the most widely accepted reason for seasickness in his keynote speech at the conference. The poison-detector theory posits that dizziness and vomiting are backups, in case the taste buds or the gut’s chemosensory system fail to pick up on a poisoned meal—the wrong kind of mushroom, say, or too much alcohol. In a mobile environment, the part of the brain processing movement interprets the action as dizziness and, through neural pathways, alerts the “vomit center” located in the medulla, a part of the brain above the spinal cord. And with luck, there are a few moments before the signal kicks in so that you can consider the direction of the wind.

If Noah indeed had an ark, he likely had a hold full of queasy monkeys, lions, and elephants. Most animals have the backup poison detector, vomiting when unbalanced, and suffer badly from motion sickness—my cat tells me his carsickness is reason number one for lack of employment and general motivation. In fact, the inner ear’s influence on motion sickness was first confirmed when researchers surgically removed the vestibular systems of monkeys and dogs. Without a functioning inner ear, the animals could not be made motion sick.

Researchers at the National University Hospital of Iceland in Reykjavík are currently examining the inner ear of fin whales to understand the adaptation of marine mammals to their fluid world. Their vestibular systems are relatively small and underdeveloped compared with terrestrial mammals, likely causing less sensitivity to surrounding movement. Whales probably don’t get seasick. Fish, however, have succumbed to motion sickness during a zero-gravity plane ride, evidenced by spinning around, doing somersaults, and generally acting confused, according to one 2009 study. Frogs behave the same way when they fly into space.


Motion sickness is a constant threat to astronauts during their adaptation to weightlessness and can have lethal consequences if they vomit inside their spacesuit. So, in 1970, NASA promoted two male bullfrogs—selected because their inner-ear structure is similar to humans—to the position of space amphibian. From NASA’s Wallops Station (now called Wallops Flight Facility) in Virginia, the Orbiting Frog Otolith spacecraft, a meter-high cone-shaped unit with a frog pool, piggybacked on an unmanned launch vehicle into a low Earth orbit. The five-day mission, tracking the frogs’ reactions with microelectrodes surgically implanted in the inner ear, provided an understanding of what kind of movement causes motion sickness in a frog. Once the experiment was over, the frogs died in space (as planned).

Motion sickness is tied to oddly specific movements. We can get sick skiing, but not cycling. We can get sick riding camels, but not horses. The difference is with the frequency of the movement. Horses and bicycles move at fast frequencies, too fast to confuse the inner ear. There is a Goldilocks frequency of movement—not too fast, not too slow—that triggers the disconnect. On large commercial airplanes, less than 0.5 percent of people get motion sickness, while 25 percent do on smaller, slower-moving planes used for short-haul flights. A 1982 study of British military personnel showed that in moderate seas some 25 percent suffered seasickness, while 70 percent did in rough seas with higher swells. And when sailors recover from the nausea—and even for those who don’t suffer seasickness at all—they are in fact still seasick without realizing it.

In accident reports, for example, seasickness is rarely claimed to be the reason, unless the person involved was flat-out sick with a green face. That, experts think, is a risky assumption. Long after overcoming nausea, a fisherman with a seasick brain continues to experience fatigue, a change in blood pressure, and distorted spatial recognition. “They may feel good enough to work,” says Icelandic physician Hannes Petersen, “but the brain is really behaving as if it’s falling asleep.”

Petersen has been looking at the hidden health hazards of seasickness for over 20 years. At medical school in Sweden, his doctoral research was on the role of the inner ear in postural control in humans. Fresh from school, he was hired as a part-time medic on rescue helicopters, a job that initially seemed unrelated to his research. The work dispatched him to car accidents, avalanches, and Iceland’s empty highland region—every far-off place in need of acute assistance. But mainly he found his work took him out to sea. Fishermen were the most common patients at sea, and compared with people in similar professions on land, such as construction workers, fishermen were far likelier to suffer a head injury, lose a limb, or fall from a height. Petersen now thinks seasickness is probably to blame for many of the accidents among sailors, both at sea and back on land.

Icelandic physician Hannes Petersen

Icelandic physician Hannes Petersen has spent over 20 years studying the hidden health hazards of seasickness.

For the first three to four days of sailing, the brain adapts to the new environment by switching balancing sensors, learning to dismiss the inner ear’s reaction, and relying instead on the body to interpret movement—getting your sea legs. During the transition, and every time the weather worsens, novel tasks and cognitive tasks involving spatial orientation are particularly difficult. Such work should, in fact, be avoided for safety reasons. Then, when the ocean calms again, the body eventually returns to relying more on the inner ear. In the unpredictable North Atlantic, the brain switches back and forth between these balancing sensors throughout a multiday trip, with the final adjustment happening on terra firma—overcoming land sickness.

Land sickness, clinically known as mal de debarquement, is when the ground feels unsteady. The intensity depends mostly on the individual—some may feel just a slight sensation for a few minutes, while others may have difficulty falling asleep for a couple of nights because the bed feels as if it’s moving. But the feeling of discomfort usually disappears before the actual adjustment happens. Just like seasickness causes people to miscalculate a swinging boom, miscalculations of where your body is in space can happen when driving or climbing up stairs. While some Icelandic fishermen claim to have their own rules for the first few days on land—they may avoid driving, for example—this lingering safety hazard is often underappreciated. Petersen and his colleagues surveyed 262 Icelandic fishermen in 2019 and found that they are more likely to visit a hospital while on land than is the general population. “Maritime safety should not stop on land,” Petersen says.


Iceland has a desolate highland interior with rocky gravel roads seemingly going from nowhere to nowhere. The horizon is the only thing dividing the scenery: black ground below, a gray or blue sky above—like the ocean on a calm day. One of my earliest childhood memories is of sitting in the back seat of a rusty jeep, with my father at the helm, using a roadmap printed on yellowing paper. My mom had stayed at home and my older brother wished he had: he was carsick. He always struggled with carsickness more than I did, and for a cynical while I suspected him of just wanting an invitation to the front seat. “Look out the window,” my father would say in a voice loud enough to overcome the old engine. Like the passengers on the whale watching boat I observed much later, we couldn’t see the horizon—but not because of fog; we weren’t tall enough to see out the window.

About one in three people is considered highly susceptible to motion sickness. These people get seasick from less movement than others, take longer to adapt to movement, and lose their adaptation quicker if the movement isn’t sustained. Who will suffer is nearly impossible to predict, but there are a handful of generalities. People with a dysfunctional vestibular system are alone among adults in their immunity; they also have a slow vomit response to food poisoning, supporting the toxin explanation for motion sickness. Children younger than six don’t get seasick either. Children’s hyper-susceptibility to motion sickness starts when their brain is mature enough to process and predict motion. So, nine-to-10-year-olds are over four times more likely to get sick than 30-year-olds. Women struggle more than men, particularly during menstruation and pregnancy. Surveys of passengers show a five-to-three female-to-male risk ratio for vomiting. Aerobic fitness also appears to increase the risk of motion sickness, as a fit person’s autonomic nervous system is more sensitive compared with someone who is out of shape. And while seasickness genes have not been found, seasickness is inherited within families and is more prevalent in some populations. Studies suggest that the average European, for example, has more tolerance for motion than the average Asian.

The high seas and space seem to be a great leveler, at least at the beginning. When astronauts leave for space, they have received the best possible pretraining, in aerotrim rings (a human-sized gyroscope) and reduced-gravity aircrafts. Yet, up to 70 percent of novice astronauts are destined to suffer during their first days in orbit. There is no preparation for motion sickness; endurance and avoidance are the only long-term solutions. Petersen’s 2019 survey found that some 88 percent of Icelandic fishermen reported having experienced seasickness, mostly at the beginning of their careers. The more time they spent at sea, they reported, the less they experienced seasickness, although about 28 percent still suffered at the beginning of each trip. Many of them reported idiosyncratic ways to avoid and cure seasickness.

Astronaut Charles J. Camarda aboard NASA's KC-135 aircraft

Astronauts often struggle with motion sickness, especially when new to space travel. To train for the effects of weightlessness, they spend time on NASA’s KC-135 aircraft, also known as the “vomit comet,” which flies a series of parabolic patterns to simulate free fall. Photo by Science History Images/Alamy Stock Photo

In 1838, the prestigious medical journal The Lancet reported that “the best treatment of sea-sickness” would be to place the patient with eyes covered in a hammock slung with long strings and on deck as near the center of the ship as possible. The article added that “if any palliative be given, it should be large doses of ammonia with opium.” It’s sound advice, minus the opium and ammonia. Lying down at the ship’s midpoint with the eyes on the horizon and with minimal head movement works when the weather on deck is not too bad. It also helps to lie down in your cabin, eyes closed: avoid reading books or smartphones. Eat whatever you find beneficial before setting sail (whether heavy on proteins or heavy on carbs, the jury is out) and drink water to avoid dehydration—no alcohol, and no smoking either, since nicotine is a poison. But, for heavy smokers that advice could backfire, since they would experience withdrawal symptoms, too. Some studies suggest that ginger and ginger ale work to reduce nausea, but the evidence is weak, as is any proof that wristbands and seasickness patches mimic acupressure.

Drugs only delay the impending habituation, rendering them useless for anything but short trips. Nearly all of the available seasickness medicines were invented decades ago to counter nausea or vertigo by clamping down on the vestibular system—like promethazine given to people after surgery and the popular over-the-counter Dramamine (dimenhydrinate) with a range of side effects in the small print. The most effective drug, not causing the usual drowsiness, is probably Scopdex. But by taking it, you might develop a drug habit—it contains the stimulus amphetamine to counter the sedation. In fact, it’s banned for anything but military use. The pharmaceutical industry does not consider motion sickness a priority, and while researchers have tested various formulations on animals, the basic number of drugs to treat motion sickness hasn’t changed much over the past 15 years.

But keep watching the research horizon, and you’ll see solutions rising from new technology.


At the birth of widescreen cinema with stadium seating in 1896, eager viewers in the front-row seats reported the unpleasant sensation of vection, causing the body to feel like it’s moving when it’s not.

This visually induced motion sickness was milder than seasickness, as well as easier to cure: look away or close your eyes. Until virtual reality and simulators entered the mainstream, this type of motion sickness was not given much attention. Now, in today’s even more visually driven era of entertainment, it is both a rising problem and a potential solution.

“I try not to make anyone sick here,” says Franck Assaban, a French physical therapist, holding virtual reality goggles in the hallway of the conference building. The goggles play animated sequences from calm to choppy oceans—and often pleasantly sunny ones—while the viewer stands on a raft that moves with the boat, up and down, up and down. Patients, or pretend passengers, can hold onto a built-in railing and practice maintaining balance as the “sea” moves—riding the waves and experiencing the natural movement of seasoned sea legs, which require the accurate anticipation of motion. The simulator can train people to have sea legs before setting sail, Assaban says. The training is aimed at people who suffer from motion sickness, but it’s also useful for those who go on infrequent but long boat trips, like expedition scientists. They have to be willing to commit to time-consuming lab training. “The entire treatment is about 10 to 30 sessions, usually two times a week,” Assaban explains. He claims to have helped, so far, a woman who fell in love with a man living on a boat but who found it impossible to spend five minutes on the boat, let alone spend the night.

virtual reality sea sickness simulator

French physical therapist, Franck Assaban, created a virtual reality regimen to train people to adapt to seasickness before heading onto the water.

I try the simulator. It is immersive and powerful. Regardless of how well the virtual world can be applied to real-life scenarios, it occurs to me that the training gives people more sense of control or empowerment. Like traveling in a car: the passenger may be carsick, but the driver rarely suffers because the driver can predict the vehicle’s motion. Psychologists at the University of Westminster recently tested how conscious breathing techniques might work on seasickness and found that after moderate practice the exercise was generally half as effective as taking pharmaceutical drugs. The breathing technique is simple but empowering—another version of the British saying “Keep calm and carry on.”

On the last afternoon of the conference, guests are scheduled to go sailing up the Eyja Fjord, but the event is canceled and the group heads to the bars of Akureyri instead. Whatever the reason—Petersen claims feasibility and cost—I am relieved. On Icelandic vessels, at least the ones I have worked on, seasickness is treated with the attitude of an addict. There is no problem. Deny, deny, deny. But stepping onto a ship full of seasickness experts? Their conversations would remind me that seasickness is inevitable, and I would be wide open to experiencing the slightest symptoms.

For most of Iceland’s history, it has not been possible to leave the country without falling sick from motion sickness for a day or two, even if you won’t admit it. According to old accounts penned on calfskin, the first settler was the Swedish sailor Gardar Svavarsson in 870 or so. After spending one harsh winter in Iceland, he bailed on this remote island. As Svavarsson and his crew prepared to leave, three of the sailors ran away and colonized the rugged island instead of getting back on the boat. Why they made that mad decision is unclear and has prompted only vague explanations by historians, drawing on hypothetical social status among the crew. But being seasick sucks. Could that be the reason Iceland was first settled?