Car Sickness Occurs Because Brain Thinks It's Been Poisoned, Scientist Claims

But it can be helped.

If you often feel nauseous or dizzy when traveling in the car, it’s likely you’re suffering from motion sickness.

According to Dr Dean Burnett of Cardiff University, the symptoms are due to the brain receiving mixed messages and thinking it’s been poisoned.

The natural reaction to poison is to vomit, hence why long journeys can make us feel so rubbish.

But Dr Burnett says it’s not entirely clear why some people are more inclined to experience car sickness than others.

Eri Morita via Getty Images

Speaking on US radio programme Fresh Air to promote his new book Idiot Brain, Dr Burnett explained the common theory that motion sickness occurs because the brain is confused.

It thinks the body is still due to the fact that you’re sitting down, but it also receives other signals that you’re in motion.

“The brain’s getting mixed messages. It’s getting signals from the muscles and the eyes saying we are still and signals from the balance sensors saying we’re in motion. Both of these cannot be correct. There’s a sensory mismatch there,” he said.

“And in evolutionary terms, the only thing that can cause a sensory mismatch like that is a neurotoxin or poison.

“So the brain thinks, essentially, it’s been being poisoned. When it’s been poisoned, the first thing it does is get rid of the poison, aka throwing up.”

Reading can confuse the brain even further as the words on the page appear fixed, which is why reading in the car can sometimes make motion sickness worse.

The NHS website also says motion sickness is likely caused by the brain receiving mixed messages.

It recommends fixing your eyes on the horizon or distracting yourself by listening to music if you’re experiencing mild symptoms of motion sickness.

Other techniques recommended by the NHS include:

  • Keep still – if possible, choose a cabin or seat in the middle of a boat or plane, because this is where you’ll experience the least movement. Use a pillow or headrest to help keep your head as still as possible.
  • Look at a stable object – for example, the horizon. Reading or playing games may make your symptoms worse. Closing your eyes may help relieve symptoms.
  • Fresh air – open windows or move to the top deck of a ship to avoid getting too hot and to get a good supply of fresh air.
  • Relax – by listening to music while focusing on your breathing or carrying out a mental activity, such as counting backwards from 100.
  • Stay calm – keep calm about the journey. You’re more likely to get motion sickness if you worry about it.