Medications or illness If you have sinus congestion or a sinus or ear infection or have recently had a concussion, you may be more prone to motion sickness. People who get migraines are also more likely to get motion sickness.

Seasickness is essentially a sensory conflict within your brain. It happens when your inner ear (which handles balance and detects motion) feels the rocking of the ship, but your eyes—especially if you are inside a cabin—see a stable environment. This mismatch confuses the brain, which often interprets the discrepancy as a sign of neurotoxicity (poisoning), triggering nausea as a defense mechanism. Some people are more susceptible due to genetics, a history of migraines, or hypersensitive vestibular systems. External factors like strong odors (diesel or fish), lack of sleep, or anxiety can also lower your threshold. To combat this in 2026, many travelers use localized relief like acupressure bands or "scop" patches, but simply staying on deck and watching the horizon provides your eyes with the same motion data your ears are receiving, helping your brain reconcile the two signals and reducing the "mismatch" that causes illness.