Why do some people vomit when travelling?

You are in a car, bus, boat or plane… everything feels normal—until suddenly nausea, dizziness, and sometimes vomiting begin.

This condition is called motion sickness or air sickness. In medical science, it is described as a sensory mismatch disorder, and it is well studied in neuroscience and vestibular medicine.

What is happening in the body?

The brain constantly determines whether you are moving or stationary by comparing signals from three systems:

• Eyes (vision)
• Inner ear (balance system / vestibular system)
• Muscles and joints (body position awareness)

Motion sickness occurs when these signals do not agree.

For example:

• your eyes see a stationary interior of a vehicle
• your inner ear detects movement

This mismatch confuses the brain, particularly the vestibular system located in the brainstem and cerebellum. Medical research shows this triggers the autonomic nervous system, which can lead to nausea and vomiting.

Why does vomiting occur?

Scientific theories suggest the brain may interpret sensory conflict as a possible sign of poisoning or neurological disturbance.

As a protective response, the body activates symptoms such as:

• nausea
• dizziness
• sweating
• vomiting
• fatigue

Common triggers

Motion sickness is more likely in the following situations:

• reading or using a phone in a moving vehicle
• sitting in the back seat of a car or any other vehicle
• travelling on rough or wavy waters
• Poor ventilation inside a vehicle
• strong smells such as fuel or perfume
• long exposure to winding or uneven roads.

How to reduce or prevent it

Simple behavioural changes can significantly reduce symptoms:

Sit in the right position

• Front seat in a car
• Middle section of a boat
• Over the wings in an aircraft

Look forward

Focusing on the horizon helps the brain align visual and balance signals.

Avoid reading or phone use

Close visual focus increases sensory conflict.

Improve airflow

Fresh air helps reduce nausea signals.

Eat lightly before travel

Avoid heavy or oily meals, but do not travel on an empty stomach.

Stay hydrated

Dehydration can worsen dizziness and discomfort.

Rest if possible

Sleeping reduces sensory processing conflict in the brain.

Medical treatment options

When symptoms are frequent or severe, doctors may recommend medications such as:

Dimenhydrinate

Meclizine

These drugs work by reducing vestibular system sensitivity but should only be used under medical advice.