
Sea sickness, car sickness, space sickness – when it comes down to it, it’s all the same. But not everybody suffers the same. Some people are even lucky enough to grow out of motion sickness. Norman and Tegan talk about what’s going on when the world goes topsy-turvy, and what you can do about it. References: Motion Sickness Validating sensory conflict theory and mitigating motion sickness in humans with galvanic vestibular stimulation - Nature Are evolutionary hypotheses for motion sickness "just-so" stories? Three studies of motion sickness susceptibility – Federal Aviation Authority Genetic variants associated with motion sickness point to roles for inner ear development, neurological processes and glucose homeostasis Motion sickness diagnostic criteria: Consensus Document of the Classification Committee of the Bárány Society Survey of motion sickness susceptibility in children and adolescents aged 3 months to 18 years Hopkins History Moments: Neil A. Grauer explains how ...
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This episode is brought to you by Google Health. Stop chasing someone else's definition of health. What matters is what's healthy for you. Google Health offers a new kind of coach built with Gemini for effortless tracking, sleep insights and holistic coaching tailored to you. Visit googlestore.com to learn more and start a new relationship with your health. Requires Google Account, Google Health App, Internet and Google Health Premium Subscription. Features subject to change. Availability and results vary. Not intended for medical purposes or works independently of Gemiini apps. Check responses for accuracy.
Norman
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Alicia Simmons
why did Matthew Flinders write such saucy letters to his best friend George Bass, who really chopped off Chopper's ears? And why did they name a swimming pool after an Australian prime minister who drowned? These are the kind of historical questions we'll be asking on the Dead Can't Sue. So join me, Alicia Simmons, and me, Leigh Boucher. Find it by searching for the Dead can't sue on ABC Listen or wherever you get your podcasts. Norman do you get Motion sick?
Norman
I do, actually, and certainly, although I do sail. If I'm a passenger in a sailing boat, I can get seasick, but not when I'm at the helm.
Alicia Simmons
Interesting, interesting. So that's more of a control freak.
Norman
Well, no, I'd argue it's different because if you understand motion sickness when you're at the helm, you're really focusing on the horizon and the environment around you, and it's a bit more random when you're sitting, and so I think that's part of the reason. But is the control freak too? Yep, no question.
Alicia Simmons
Well, really understanding motion sickness is what we are delivering to you today here on what's that Rash?
Norman
The podcast where we answer the health questions that everybody's asking.
Alicia Simmons
Well, everybody's asking about motion sickness today, Norman, we had an email from Nat, who says, huge fan of the podcast. My question is, why do some people get motion sickness in cars or boats? And from Claire, who says, when I was a kid, throughout my schooling years, I got terrible motion sickness and would often throw up on long car or bus trips. I was told that lots of kids got motion sickness and I'd eventually grow out of it. It's been a couple of decades since I finished school and I still haven't grown out of it.
Norman
Oh, you're clear.
Alicia Simmons
If anything, my motion sickness has become more sensitive. Why do some people grow out of motion sickness but others don't? At the age of 37, Claire says, I assume I'll never grow out of it, but it would be good to know why. So, yes, what is motion sickness, and does it change over our lifetime? What we'll cover today in this chat?
Norman
We will.
Alicia Simmons
So motion sickness. I always assumed, Norman, that, like, biologically, humans were never meant to go faster than we could run. So in the back of my mind, that's my very, like, rudimentary reason why we should get motion sickness. But I imagine that it's a little more complicated than that.
Norman
Well, it is a little bit complicated. We're probably close to something there. I mean, we can theorize forever on it. But, yeah, we evolved to walk on the ground. We were in control. We didn't evolve to drive in a car or go in a boat. These are abnormal activities relative to human evolution. And as soon as you get onto a vehicle of some kind, you are in a situation where something else is moving against the horizon and your body is having to cope. I suppose we were. You know, I don't know whether you get motion sickness on a horse or a camel, but nonetheless, usually you're too
Alicia Simmons
distracted by your terror of the fact that you're on a horse or a camel overrides the motion sickness.
Norman
I think you could probably get motion sickness on a camel. You know, that sort of undulating thing. But you're right. We essentially evolved to walk by ourselves on the ground where we were in control, and the horizon doesn't move.
Alicia Simmons
It's interesting, you mentioned ships there and boats and floating not being part of our sort of natural repertoire of movement. The word nausea actually comes. Comes from the same word that gives us the word nautical. Like it's from the same. It's from the root seasickness. Yes. Seasickness comes from Norse, as in ships, sailing, sailors. It's the same root that gives us nautical. So the two are very entwined, at least in our language.
Norman
Now, this is going to have echoes of our yawning episode, because I suspect that just talking about motion sickness is going. I'm getting it. You feel a little bit. Bleh. You're sorry.
Alicia Simmons
Just stop spinning in your chair and it'll stop. Yeah, that's right. That's your problem.
Norman
That's true. Actually, I am in a spinning chair. Well, actually, a spinning chair. Well, we'll come back to spinning chairs in another episode.
Alicia Simmons
Okay. Okay, so we're talking about motion sickness. Can we have a bit of an explanation of what is happening inside the body when you're moving and then you have nausea as a result?
Norman
Well, first of all, this is an unpleasant condition, and you are in a Situation where you're in motion, where you're not in control of that motion. It can either be a real motion or you can be. Your eyes can be foxed by a situation where you think you're in motion, but you're actually not.
Alicia Simmons
Oh, people get it from VR goggles sometimes, like virtual reality.
Norman
They can. They can get it in space travel. You can get it in electric vehicles, where the silence of an electric vehicle doesn't give you an auditory cue that you are accelerating. I recently bought an electric vehicle and the guy who was selling it to us warned us about that and said, turn on. You know, some electric vehicles have this pseudo engine noise.
Alicia Simmons
And he said this spaceship noise.
Norman
Turn on the engine noise. And we find that the motion sickness feeling tends to go away because you've got that. He didn't say auditory cue, but that's what he was talking about. I'm not diminishing car salesmen here by not giving them the capacity to say auditory cue, but you know what I'm saying.
Alicia Simmons
So you're managing to be snobby and flex about the fact that you've got an EV now, Norman to no, no, no, no. Alongside you. So you've put on the noise in your car to stop yourself from feeling motion sick, and it's helped.
Norman
No, I never felt motion sickness to start with, but I put it on because I do miss the vroom, vroom of a petrol car. So now I've gone from vroom, vroom to eh. And I haven't had any motion sickness. And what we're talking about here is that you feel nauseous, dizzy, you feel crap. You know, the technical term is malaise. And you want to vomit. And sometimes you do vomit.
Alicia Simmons
Okay, so there's this mismatch between the eyes and movement. That's the big one we've heard about before. You're saying there's maybe a bit of a mismatch between our learned auditory cues from travelling in combustion engine cars in the past and the movement.
Norman
I think the word here is mismatch. And it's mismatch between several different sensory systems. And when your brain is in conflict, you start to get these symptoms of nausea, vomiting, dizziness and malaise. And you can get that in other situations as well. But this is with motion, where you're not in control of the motion.
Alicia Simmons
And it kind of has to do with what's happening inside our ears. Ears are not just for hearing. They're also really important for telling our brain where our body is in space. And they can get confused?
Norman
They do. So it's not the hearing part of your ears. In your inner ear, you've got this canal system which is a bit like a gyroscope, which go in different directions. They're at right angles to each other and the got hairs in them and they can detect acceleration and they can detect your position in space. And that's how you balance yourself, you know, it's called the vestibular system and it's connected to parts of the brain which help to control that. And your visual pathways are part of that process. And your hearing is also related to it because your hearing is closely related to all this as well. So your core sensory system comes together in your vestibular system and it's also your joint position as well. So where your legs are in space, where your joints are, all this goes into the brain and gets integrated. And when there's a conflict between the two, the brain doesn't like it.
Alicia Simmons
Okay, it makes sense that you don't like it or that there's a mismatch there. Why is vomiting or wanting to vomit or feeling like you might vomit the symptom that you get though?
Norman
Short answer is nobody knows. There is this toxin theory for motion sickness that the body behaves as if it's consumed a toxin.
Alicia Simmons
Oh, right. So like if you'd eaten something and it was your body's telling you to vomit, it's doing something similar.
Norman
Yeah, I mean, these are theories to explain something that's hard to explain. Nonetheless, you've got a crossover between systems here. And there are neurological connections to things like the centers which induce vomiting.
Alicia Simmons
But I mean, one of the questions we got was why does it happen to some people and others? Do we know who's most at risk?
Norman
Well, we do know that it is partly genetic. People have done what's called genome wide association studies, where you look at the pattern of what are called SNPs, single nucleotide polymorphisms. These are not mutations. This just shows the geography of your genome. And there are patterns of that which are associated with motion sickness. Explains why you can have siblings in the same family. Some people who get it and some people don't. And the other issue with these genetic associations is that women do seem to suffer from motion sickness more than men. And some of these genes are more gender specific than others. But there's no easy explanation for why women might get more motion sickness than men or males more than females.
Alicia Simmons
What about growing out of it? Is it something that you're more likely to have when you're younger.
Norman
Well, there have been surveys looking at this through the years. Looks as though rare in infancy, although one of my children had it from infancy. Little baby. We'd get on a plane and almost before the plane took off she was vomiting. And that lasted throughout her childhood. She still gets a little bit of motion sickness. In fact, there's an argument in my family between my daughters about who gets to sit in the front of the car, because in the front of the car you seem to get less motion sickness. But we'll come back to some of these solutions in a minute. Than in the back of the car. But we do have paper bags available. I've got some horror stories to tell of trips in motion sickness, I have to say, including one episode where I had a hire car and didn't have time to clean.
Alicia Simmons
I had the hire car and didn't
Norman
have time to clean it up, shut it and ran away to catch a plane and then got a very large bill for cleaning afterwards. But that's another story. But if you look at the data here, rather than my anecdotes, you know, there seems to be. There's a U shaped curve where in childhood it seems to be high, seems to drop in adolescence, can go up again in later adolescence, and then tends to go down again in adulthood. So Claire's pretty unlucky. A lot of adults do find it disappears or becomes less severe. So there is a post pubertal decline on that.
Alicia Simmons
I wanted to talk about the idea of getting your sea legs or if you like to have a bit of fun, on YouTube, you might have watched videos of like fighter pilots in flight school and they basically put them under incredible G forces to see how. How much it takes for them to vomit or pass out or whatever. And obviously those people, it either weeds out people who aren't suited to it, maybe that's one way. Or you somehow figure out how to tell your. Inform your body that this is okay and like don't freak out and don't be nauseous and just deal with it. Is there sort of like a familiarization or acclimatization process you can go through?
Norman
Well, people think there is and some people would swear by it. I think in space travel it's quite hard and they talk about sea legs. Getting your sea legs. If you talk to experienced sailors, they will admit that they still get seasick. Slightly contradicts that it goes away after a while. I think that in the more extreme the situation you're in, almost anybody can experience motion sickness. So it's really unusual. If you're in a small boat in a big sea, you're quite likely to get seasick. And there's probably nobody who's immune to it. It's really the severity of the motion and the motion disparity that causes it. So some people get it with a little bit of disparity, and some people, it requires a lot. But if you talk to experienced sailors or even fishermen, fisherwomen, their boat might be in a river and then they have to go out to sea, and it's a bit rough when they go out to sea. They will say that they get seasick during that first few minutes as they go out to sea and then it settles. So a lot of people continue to get it now. They learn how to want some ways of dealing with it. I think there's a little question. If you're at the helm, if you're a driver, you tend not to feel it because you prevent that mismatch between, say, the horizon and the feeling of motion, so that your eyes are forced into a much closer coordination because you are responsible for the directionality of the vessel or the car, and therefore you are less likely to get motion sickness. Whereas if you are not in that situation, your eyes are not forced to do it. But if you plant your feet on the deck and you focus on the horizon, you can tend to minimize, at least in the seasickness sense, that feeling of seasickness. I think they try to have all sorts of ways of doing it for space travel, but often in space travel, they need medications to help them through. So I don't think that necessarily training gets you away from the fact that if you are in extreme situations, you will still feel it, but have little techniques for trying to minimize it. And some people will find that getting below deck helps. And some people will feel that getting above deck to the front of the boat, for example, makes a difference. And I've already spoken about the car. The front of the car being the front seat seems to be less of a problem for motion sickness than wallowing around and being teased by your brother.
Alicia Simmons
I can speak from my own experience. I love fresh air. So above deck, if I can be or crack a window in a car, although it is generally frowned upon to crack a window in a spacecraft. So I suppose we do need to have some other tools at our disposal. What do we have?
Norman
So if you've got severe and disabling motion sickness, there are treatments. So there are antihistamines. They mostly have an effect on the brain or thought to have an effect on the brain or on the gastrointestinal system, making vomiting less likely. There's also drugs called scopolamine or hyosine. Those are the ones that you tend to put on the back of your ear on a patch, which actually interfere with nerve communication. Nerves communicate with each other. They can give you a dry mouth because they're atropine like drugs. And they are the sort of drugs that anaesthetists can give you before anesthetic to prevent vomiting, you know, when they're inducing an anesthetic. And then there are some new drugs that haven't necessarily been approved worldwide which interfere with very specific brain pathways. So there are drugs which have an effect, and sometimes people have got to play around with those drugs to work out which ones them best.
Alicia Simmons
So there's a bit of history here about using antihistamines and figuring out that there was a kind of side effect that was that it helped with motion sickness. There's a story from the 40s where this woman who had hives was going to the Johns Hopkins Allergy clinic, but she had to ride the trolley. The clang, clang, clang, went the clanga trolley to get to the clinic. And she would get really nauseous on the trolley, and they gave her an antihistamine because she was there for hives. And when she was traveling home on the trolley, she didn't feel sick anymore. And so that sort of sparked some research into antihistamines being helpful with motion sickness. I'm just wondering what the connection is between the mechanism of these drugs.
Norman
We've spoken about this before. As soon as you find that a drug has an effect on a condition, usually by accident, then you launch medical research or theories to explain why. And I once did an interview with a researcher who found that a drug had an effect. It was a surprising effect. And I asked why. He said, I'm not interested in why, it just works. And any theory I'm going to give you is probably so. They don't really know why, but they are effective. And it's just that antihistamine drugs have all sorts of effects on the nervous system, on the gut, on the sort of cells in your body that react to toxins, for example, comes back to that toxic theory that if it's simulating, you know, if it's imitating the reaction of a toxin, then antihistamines can help that. So there's lots of different reasons why antihistamine pills could help. And it's probably several actions at Once, because they're kind of messy drugs, they have lots of different effects on the body.
Alicia Simmons
Well, the timing of this particular episode was quite fortuitous because obviously it was the 40s, as I said before. And so they ended up turning into something that they called Operation Seasickness, where when they had soldiers leaving to travel across the sea, they put them into three different groups that got either this tablet before they went, this tablet on the journey if they got seasick, or a placebo. And they did show that the tablet did make a difference in seasickness, unlike many of the kind of remedies that are marketed to help with motion sickness. And perhaps there isn't as much evidence for.
Norman
Yeah, there's some evidence for ginger, particularly raw ginger. There are compounds there which speed stomach emptying and that may reduce nausea. So if you've got a full stomach when you get on a boat or a plane, nausea, nausea may translate into vomiting more easily. So ginger may well have an effect and certainly not going to do you any harm to try that. Acupressure. So there are wristbands that work by putting pressure on acupressure points and if that does work, it's probably placebo. Mindfulness breathing has a physiological effect on the body and can be a distraction. Some people put rubber straps on the back of the car, rubbing against the ground to remove the static inside the car. I think that's probably the thing. Is that a thing?
Alicia Simmons
I remember seeing those.
Norman
It used to be a thing in
Alicia Simmons
the 90s, I think it was a thing. You'd see these cars with something trailing behind them.
Norman
But I've never seen a randomised trial of motor vehicles and straps so fair.
Alicia Simmons
So, I mean, Norman, you've rattled off a lot of different remedies here and sounds like they have varying levels of evidence behind it. I would actually love to hear from folks if you found something that works for you. Cause vibes wise, Norman, that really kind of seems to be the message here. If you sort of figure out what works for you and just, just ignore the haters.
Norman
Yeah, send us your N of 1 Studies in Motion sickness, we're all ears, all eyes, all feet, full vestibular systems. Yeah, we are on stable ground, ready to hear from you.
Alicia Simmons
So bottom line, for Nat and Claire, who have sought us and our advice out.
Norman
So Clare's probably got the genes. Sorry, Clare, but there are things that you can do to help yourself. But don't stop travelling, you know, have fun. If you're on a boat, insist on taking the helm, even if you don't know what you're doing and there are treatments.
Alicia Simmons
Well, thank you Claire Annette, for your questions. We love getting them. Our email address is thatrashbc.net au so
Norman
what's in the mailbag?
Alicia Simmons
We had a chat recently about what you can do to reduce your cancer risk and a kind of sobering question from bec. I studiously abide by the health guidelines regarding diet, exercise, weight management and all of the lifestyle factors attributed to living a long and healthy life. My mother was a two pack a day smoker at her worst and our one sitting room had no ventilation. Our hair, clothes and bodies all reeked of cigarette smoke. Thinking about this regarding my own cancer risk, is there a time that I can say that I'm no longer at risk of developing cancer related to passive smoking? Additionally, can I presume that the breast cancer I did have at age 42, when I had no predisposing factors myself, was caused by passive smoking?
Norman
It's a really good question, bec and it is sobering. So passive smoking in childhood and also pregnant women who might be exposed to passive smoke. Western Australian research has shown that it actually can change the lungs of the baby of the fetus in utero and increase the risk, for example, of asthma when the baby is born. So that's not just smoking in pregnancy, it's passive smoking in pregnancy having an effect on the fetus. So passive smoking, when you are exposed to it, particularly in childhood but also in adulthood, the main risk is coronary heart disease. So the risk is not as high as smoking itself, but it's there and significant. I too grew up with huge amounts of inhalation of passive smoking, and you do wonder what sort of effect it had on you. Now, let's assume there was a moment where your exposure to passive smoking disappeared. You'd have to extrapolate from smoking cessation itself in terms of the risk reduction. If you stop smoking cigarettes, your risk drops actually within hours of coronary events, you know, sudden death, heart attack, those sorts of problems. Now, what's known from smoking cessation is that your cancer risk, particularly lung cancer, does decline, but it declines more slowly and never quite goes away. It would be impossible to say whether your breast cancer Beck at 42 was related to your passive smoking exposure because that would be much less than smoking itself. But it was from an early age, so we can really tell. Impossible to know.
Alicia Simmons
It's tricky with this cancer risk story because I feel like whatever we're talking about here, we're talking about dialling up or dialling down your risk. But you never get to 100%. You're definitely gonna get cancer. And you never get to zero. You'll never get cancer. And you're only ever moving along a spectrum. And you never get to know where you actually sit or where you would have sat without that intervention.
Norman
That's right. And you're doing the right thing, Beck. You've got a healthy lifestyle that's gonna bring your cancer risk. Well done.
Alicia Simmons
All the best, Bec. Thanks so much for the email. You can send us your questions, your feedback, whatever you like. Our email address is thatrashbc.net au before we go, this is a bit of a gear shift, but if you are a podcast lover, which I'm guessing you are if you are listening to this did you know that your kids can also discover the joy of screen free ear entertainment just the same as you?
Norman
Indeed they can. All the best, funniest and well, secretly educational. But don't tell them that podcasts are on abc.
Alicia Simmons
Listen, you can unearth Adventures with Gardening Australia junior A mini Costa. Exactly. Tiny Costa. Tiny beard. Explore Big Questions with Imagine this and learn about the world with news time.
Norman
All of those shows and a whole lot more are available for free. Cause it is the ABC in the child safe part of abc. Listen, just look for the kids tab. Are we in the child safe part? I hope we are.
Alicia Simmons
I don't know if we're child safe all the time, Norman. Anyway, while your kids ears are busy, maybe you get to sneak in another episode of what's that Rash. So go on then, look for the kids tab in abc.
Norman
Listen and we'll see you next week.
Alicia Simmons
See you then.
This episode dives deep into the causes, mechanisms, and experiences of motion sickness. Hosts Norman and Alicia Simmons respond to listener questions about why some people are more prone to motion sickness, why it can persist or fade with age, and how to cope with or prevent it. Anchored in both scientific explanations and personal anecdotes, the discussion focuses on the genetics, physiology, and psychology of motion sickness—a condition familiar to many, but still not completely understood.
Questions from listeners Nat and Claire spark the conversation:
Norman shares he is prone to seasickness as a passenger but not at the helm, connecting this to the role of focus and control ([01:09–01:23]).
"If I'm a passenger in a sailing boat, I can get seasick, but not when I'm at the helm."
— Norman ([01:09])
Alicia humorously suggests this is a "control freak" trait, prompting Norman to note the importance of visual focus and sense of control ([01:20–01:23]).
Norman explains that humans evolved to walk on the ground and be in control of their movement; riding in vehicles or boats presents the body with novel challenges ([02:41–03:49]).
The word "nausea" has roots in "nautical" and "seasickness," showing the historic link between motion and sickness ([03:49]).
"The word nausea actually comes from the same word that gives us the word nautical... From the root seasickness."
— Alicia ([03:49])
The core trigger is a conflict ("mismatch") between the senses—primarily between the vestibular system in the inner ear, vision, and, to some extent, auditory cues ([06:01–06:58]).
The vestibular system detects acceleration and spatial position, integrating sensory information. When the brain receives conflicting signals, symptoms like nausea, dizziness, and malaise occur ([07:08–08:04]).
Example: In electric vehicles, the absence of engine noise removes a familiar sensory cue, causing motion sickness in some ([05:03–06:01]).
"It's mismatch between several different sensory systems. And when your brain is in conflict, you start to get these symptoms of nausea, vomiting, dizziness and malaise."
— Norman ([06:37])
There is a "toxin theory": the body may respond to sensory mismatch as if it has ingested a toxin, triggering the urge to vomit ([08:14–08:41]).
"There is this toxin theory for motion sickness that the body behaves as if it's consumed a toxin."
— Norman ([08:14])
Genetics play a role: Genome-wide association studies show certain genetic patterns make some individuals more susceptible ([08:46–09:32]).
Women seem more affected than men, possibly due to gender-specific genetic factors, though the reason isn’t entirely clear ([08:46–09:32]).
Motion sickness in childhood is common, can peak in adolescence, and often declines in adulthood—but not always ([09:35–10:54]).
"There's a U shaped curve where in childhood it seems to be high, seems to drop in adolescence, can go up again in later adolescence, and then tends to go down again in adulthood."
— Norman ([10:19])
On control and motion sickness:
"If you are a driver, you tend not to feel it because you prevent that mismatch between, say, the horizon and the feeling of motion, so that your eyes are forced into a much closer coordination..."
— Norman ([12:34])
On the origins of motion sickness:
"We essentially evolved to walk by ourselves on the ground where we were in control, and the horizon doesn’t move."
— Norman ([03:37])
On antihistamines and medical serendipity:
"As soon as you find that a drug has an effect on a condition, usually by accident, then you launch medical research or theories to explain why."
— Norman ([15:46])
Motion sickness arises from evolutionary roots, sensory mismatches, and a lucky or unlucky dip in the genetic lottery. While medication and certain environmental or behavioral tweaks can help, the experience is highly individual, and even experts aren't immune. The episode closes with encouragement to keep traveling, experiment with different solutions, and not to let motion sickness dictate your adventures.