1At a glance
- Common Name
- Motion Sickness, Mal de Mer
- Primary Cause
- Sensory conflict between inner ear, eyes, and body
- Typical Onset
- Within minutes to hours of exposure to motion
- Common Symptoms
- Nausea, vomiting, dizziness, cold sweats, pallor, fatigue
- Prevention Methods
- Medication (prescription/over-the-counter), acupressure, behavioural strategies
- Effect on Diving
- Can impair judgement, increase dehydration risk, and lead to cancelled dives
- Risk Factors
- Previous history of motion sickness, anxiety, enclosed spaces, rough seas
2How sea sickness works
Sea sickness is primarily a result of sensory conflict. The brain receives signals from three main sources that determine balance and orientation: the eyes, the inner ear (vestibular system), and proprioceptors (nerve endings in muscles and joints). When these signals are incongruent—for example, the inner ear detects motion while the eyes perceive a stable cabin interior—the brain becomes confused.
This sensory mismatch can trigger a response in the brainstem, specifically in the area postrema (also known as the chemoreceptor trigger zone), which is responsible for initiating vomiting. The resulting physiological cascade can include activation of the parasympathetic nervous system, leading to nausea, increased salivation, and gastric distress, alongside sympathetic nervous system activation, causing cold sweats and pallor.
Factors influencing an individual's susceptibility include genetics, anxiety levels, hydration, and the type and intensity of motion. Repeated exposure to motion can sometimes lead to adaptation, where the brain learns to reconcile the conflicting signals, a process known as habituation or 'getting your sea legs'.
3Prevention Methods for Sea Sickness
| Method | Description | Onset of Effect | Potential Side Effects |
|---|---|---|---|
| Oral Antihistamines | Over-the-counter medications like dimenhydrinate or meclizine, often taken before symptoms appear. | 30-60 minutes | Drowsiness, dry mouth, blurred vision |
| Scopolamine Patch | Prescription transdermal patch worn behind the ear, providing continuous medication release. | 4-6 hours | Dry mouth, blurred vision, dizziness |
| Acupressure Bands | Elastic bands with a plastic stud that applies pressure to the P6 (Nei-Kuan) acupressure point on the wrist. | Immediate | Mild skin irritation |
| Ginger | Natural remedy consumed as capsules, tea, or crystallised ginger, believed to aid digestion and reduce nausea. | Varies (30-60 minutes) | Mild heartburn, belching (rare) |
| Behavioural Strategies | Focusing on the horizon, staying on deck in fresh air, avoiding strong odours, consuming light meals. | Immediate | No direct side effects |
4What sea sickness means for your liveaboard trip
Experiencing sea sickness on a liveaboard can significantly detract from the diving experience. Symptoms such as nausea, vomiting, and dizziness can make it difficult to participate in dive briefings, prepare equipment, or even don a wetsuit. Severe cases may lead to missing planned dives, which is particularly disappointing on a trip specifically designed for diving.
Furthermore, dehydration from vomiting can be a concern for divers. Dehydration is a known risk factor for decompression sickness (DCS), making it vital for divers suffering from sea sickness to manage their fluid intake carefully and consider their physical condition before diving. Some medications for sea sickness can also cause drowsiness, which could impair judgement or reaction times underwater, so it is important to test any medication before diving.
Liveaboards are often designed with features to mitigate sea sickness, such as stabilisers on larger vessels or cabins located centrally and low in the hull where motion is less pronounced. Crew members are usually experienced in assisting guests with sea sickness, offering advice, and providing comfort. It is always advisable for divers prone to sea sickness to discuss their concerns with the liveaboard crew and their dive guide.
5Factors Influencing Motion Sickness Risk on Liveaboards
| Factor | Low Risk Impact | Moderate Risk Impact | High Risk Impact | Description |
|---|---|---|---|---|
| Vessel Size | Large liveaboards (over 30 metres / 100 feet) | Medium liveaboards (18-30 metres / 60-100 feet) | Small liveaboards (under 18 metres / 60 feet) | Larger vessels generally have greater stability and less pronounced motion. |
| Sea Conditions | Calm seas (wave height under 0.5 metres / 1.6 feet) | Moderate chop (wave height 0.5-1.5 metres / 1.6-5 feet) | Rough seas (wave height over 1.5 metres / 5 feet) | Higher waves and swells increase the magnitude and frequency of ship movement. |
| Cabin Location | Midship, lower deck | Forward/Aft, lower deck | Upper deck, especially bow/stern | Motion is typically least noticeable near the centre of gravity and lower in the vessel. |
| Individual Susceptibility | No prior history of motion sickness | Occasional motion sickness in specific conditions | Frequent and severe motion sickness | Personal tolerance varies widely; prior experience is a strong indicator. |
| Pre-trip Preparation | Adequate sleep, light meals, preventive medication | Some preparation, but inconsistent | Poor sleep, heavy meals, no preventive measures | Good preparation can significantly reduce the likelihood and severity of symptoms. |
6Common misconceptions
Myth: Sea sickness is all in your head. Fact: While anxiety can exacerbate symptoms, sea sickness is a genuine physiological condition caused by a conflict between sensory inputs to the brain. It is not purely psychological and affects individuals regardless of their mental fortitude.
Myth: Once you get sea sick, there's nothing you can do. Fact: While symptoms can be distressing, there are many effective remedies and strategies to alleviate sea sickness, even after it has started. These include moving to fresh air, focusing on the horizon, consuming ginger, or taking medication.
Myth: Alcohol helps you relax and prevents sea sickness. Fact: Alcohol, especially in excess, can actually worsen sea sickness symptoms. It can contribute to dehydration and affect your balance and inner ear function, making you more susceptible to motion sickness.
Myth: If you've never been sea sick before, you never will. Fact: Susceptibility to sea sickness can change over time due to various factors including fatigue, stress, specific sea conditions, and even hormonal changes. A previous lack of symptoms does not guarantee future immunity.
FAQ
What are the common symptoms of sea sickness?
Common symptoms of sea sickness include nausea, vomiting, dizziness, cold sweats, pallor, and a general feeling of malaise. Some individuals may also experience headaches or increased salivation.
Can children get sea sickness on liveaboards?
Yes, children are generally more susceptible to sea sickness than adults, particularly those between the ages of 2 and 12. Parents should consult a paediatrician for appropriate preventative measures or medications.
What non-medicinal methods can help prevent sea sickness?
Non-medicinal methods include staying on deck and focusing on the horizon, getting plenty of fresh air, avoiding reading or looking at screens, eating light, bland meals, and using acupressure bands.
Are there any side effects from sea sickness medication?
Yes, common side effects of over-the-counter sea sickness medications, such as antihistamines, can include drowsiness, dry mouth, and blurred vision. Prescription patches like scopolamine can have similar effects. Always test medication before diving.
Should I take sea sickness medication before symptoms start?
For optimal effectiveness, many sea sickness medications work best when taken preventatively, before symptoms begin. This allows the medication to be absorbed and start working to block the signals that cause motion sickness.
Does sea sickness affect my ability to dive safely?
Yes, severe sea sickness can impair your ability to dive safely. Vomiting can lead to dehydration, which is a risk factor for decompression sickness. Drowsiness from medication can also affect judgement and reaction times underwater. Always assess your fitness to dive if you are feeling unwell.