What is Motion Sickness?
Motion sickness is a common condition that happens when you feel movement or believe you are moving. The symptoms can vary greatly and include effects on the stomach and gastrointestinal system, the brain and central nervous system, as well as automatic body functions. Some people are more likely to get motion sickness than others; certain people might feel sick with slight movement, while others may need considerable motion to feel ill.
Hippocrates, an ancient Greek physician, was the first to describe motion sickness symptoms when he wrote, “sailing on the sea proves that motion disorders the body.” The primary symptom of motion sickness, nausea, is based on “naus,” a Greek word for ship (like in the term “nautical”).
Motion sickness often happens when what you’re sensing or feeling doesn’t match up with what you’re expecting. While doctors and scientists don’t fully understand the exact brain and body processes behind motion sickness, different strategies and remedies have been developed to prevent and reduce the effects of this condition.
What Causes Motion Sickness?
Motion sickness usually happens when you’re traveling by air, sea, or road or when you’re using video games or virtual simulators. The most common explanation for motion sickness is the “sensory conflict and neural mismatch theory”. This theory talks about a sort of ‘mix-up’ or conflict between what you see, the balance system in your ears (called the vestibular system), and the system in your body that helps you sense where your body parts are and how they’re moving (known as the somatosensory system).
When you’re in motion, messages from your ear’s balance system reach an area in the brainstem called the vestibular nuclei. This area also gets inputs from your vision and your body’s sense of position. Then, messages from the vestibular nuclei go to a part of the brain called the temporoparietal cortex through a part called the posterolateral thalamus, which ultimately causes reactions like vomiting.
So, if there’s a mismatch between what your body expects and what it actually experiences in terms of motion and position, it can set off a chain reaction of motion sickness symptoms.
Risk Factors and Frequency for Motion Sickness
Motion sickness can occur in almost everyone who has a working balance system in their inner ear and is exposed to certain triggers. People who’ve lost all function in this part of the ear don’t get motion sickness.
Not everyone is equally likely to get motion sickness. It can depend on a number of factors including:
- Your sex – women are more likely to get motion sickness than men.
- Your age – motion sickness usually begins around age 6, peaks at age 9, and then gets less common during the teenage years as people get used to the triggers.
- Older people are the least likely to get motion sickness.
- Your fitness level – people with high levels of aerobic fitness may be more likely to get motion sickness. It is thought that their autonomic system, which controls things like heart rate and digestion, may react more easily to triggers.
- Medical conditions – people with balance issues, problems with the inner ear, Meniere’s disease, or migraines are more likely to experience motion sickness.
- Hormones – changes during pregnancy and the menstrual cycle can make you more likely to get motion sickness.
Signs and Symptoms of Motion Sickness
Motion sickness has a variety of symptoms. The most common ones include nausea, vomiting, cold sweats, pale skin, headache, feeling sleepy, yawning, loss of appetite, and increased saliva. Usually, these symptoms start after someone experiences a motion they’re not used to. There’s a specific collection of symptoms called “sopite syndrome” which involves extreme tiredness and sleepiness that can last from several hours to even a few days after being exposed to the unfamiliar motion. This can make a person appear bored, uninterested, easily annoyed, and show changes in their behavior.
In some cases, the symptoms of motion sickness can be severe. These might include being unable to walk, being incapacitated, having trouble with balance, non-stop retching, and isolating oneself socially. If the early and milder symptoms of motion sickness aren’t identified quickly, it could lead to a delay in getting treatment.
Testing for Motion Sickness
Motion sickness can be diagnosed by your doctor using your medical history and a physical exam. Most of the time, further tests like blood work or x-rays aren’t needed, especially if you’ve had motion sickness before or your symptoms clearly point to motion sickness.
However, if your motion sickness symptoms suddenly appear out of nowhere, your doctor might want to check for migraines. Migraines are often closely linked with motion sickness. In fact, treating migraines not only can help with the headaches, but can also improve dizziness and symptoms of motion sickness often experienced alongside them.
It’s very important to rule out serious conditions that could cause motion sickness. One of these is an obstruction in the basilar artery, a crucial vessel carrying blood to your brain. Dizziness and motion sickness can sometimes be the first symptoms. People with this artery blocked may also suddenly experience double vision, slurred speech, difficulty swallowing and suddenly falling. If your doctor is worried about this, they might have you get a type of CT scan, called CT angiography, to make sure the basilar artery isn’t blocked. Once this severe artery obstruction is dismissed, your doctor can then investigate less serious conditions which can cause similar symptoms – like benign paroxysmal positional vertigo (a type of dizziness due to problems in the inner ear), vestibular migraine (a type of migraine that is associated with balance problems), or vestibular neuritis (inflammation of the inner ear usually caused by a viral infection).
Treatment Options for Motion Sickness
If you are prone to motion sickness, there are several behavioral changes you can make to help prevent or reduce your symptoms. These include limiting your head and body movements, avoiding reading in moving vehicles, sitting in a forward-facing seat or driving the vehicle, focusing on the horizon, breathing mindfully, avoiding nicotine, listening to calming music, and avoiding traveling in difficult conditions.
One of the most effective longer-term strategies is gradually getting your body used to motion, a process called habituation. It’s a time-consuming approach that might take several weeks but doesn’t have the side effects (like drowsiness or blurred vision) that some drugs do. In fact, with enough continuous exposure to the motion, your symptoms may go away within a few days. However, if you don’t experience motion regularly, this method might not work in the long run.
There are also some alternative therapies. For instance, consuming ginger has been shown to help with vomiting, a common symptom of motion sickness. Acupressure bands, which you wear on your wrist, have also shown some promise in treating nausea and vomiting, although more research is needed.
Medications are sometimes used to treat motion sickness, although these only partially effective and can have side effects. Different types of medications that may be considered include anticholinergic medications like Scopolamine, and antihistamines. For example, diphenhydramine is a popular over-the-counter drug used for treating motion sickness (although it can cause drowsiness). Medicines are most effective when used in advance or at the very start of symptoms, so try them out in a safe environment before using them while traveling or working.
Another type of drug, sympathomimetic, is sometimes used, most commonly during space flights. Sympathomimetics like dextroamphetamine work in combination with other medications for motion sickness, but there is a risk of dependency.
Some therapies are not typically recommended for motion sickness. For example, dopamine antagonists and serotonin receptor antagonists, while they are effective at treating nausea and promoting digestion, are not effective at preventing motion sickness symptoms.
If you are pregnant and suffer from motion sickness, certain medications used for morning sickness might be safe to use. These include meclizine and dimenhydrinate. However, other drugs like Scopolamine and promethazine should be used with caution during pregnancy.
What else can Motion Sickness be?
If someone has suddenly started experiencing motion sickness without any clear reason, it might be due to conditions related to the vestibular system, which controls balance and eye movements. This could include:
- Benign paroxysmal positional vertigo (a condition where certain head movements trigger vertigo)
- Vestibular migraine (a type of migraine that can cause problems with balance)
- Vestibular neuritis (an inflammation of the inner ear)
- Exposure to medication that can harm the inner ear
It’s important to investigate these possibilities to find the cause of the motion sickness. In these cases, a neurologist or a specialist in vestibular disorders might be needed for further consultation and treatment.
On the other hand, in patients who have a high risk for strokes, sudden and severe symptoms like dizziness with no previous history of motion sickness might signal a cerebrovascular event (stroke). So, it’s crucial to remain alert to this possibility, particularly if the symptoms are new and severe, and there’s no previous history of motion sickness.
What to expect with Motion Sickness
People who have experienced motion sickness in the past are likely to experience it again if they are exposed to a similar situation, unless they are able to get used to it over time. As the severity of symptoms can vary greatly, it’s important for patients and their healthcare providers to discuss the potential drawbacks and advantages of medication treatment on a case-by-case basis.
Possible Complications When Diagnosed with Motion Sickness
Most people who experience motion sickness tend to have mild to moderate symptoms that go away on their own. Typically, once the motion causing the sickness stops, the symptoms usually disappear within a day. However, a small number of people might have severe symptoms, like intense nausea and vomiting, which can lead to dehydration, electrolyte imbalances, or even tears in the esophagus.
Common Symptoms and Effects:
- Mild to moderate symptoms that typically resolve on their own
- Resolution of symptoms usually within 24 hours after the motion stops
- Severe symptoms in some cases, including intense nausea and vomiting
- Possible dehydration due to severe symptoms
- Potential electrolyte disturbances because of intense vomiting
- Esophageal tears in severe cases
Preventing Motion Sickness
Preventing motion sickness is more effective than treating it once it occurs. Therefore, it’s crucial to identify and avoid anything that triggers it. Patients can use strategies such as preparing in advance, getting used to the conditions that trigger motion sickness, and possibly taking medication to manage their symptoms. If medication is required, it’s important to be aware of potential side effects, which can include drowsiness and difficulties in thinking or memory, in order to reduce any associated risks.
