What the health: What causes motion sickness?

29 Aug 2019

car sick

A possible cause of motion sickness is a mismatch amongst the systems our body uses to detect motion.

Imagine you are sitting in a car. When the car starts to move you feel this movement as cells in your ears, muscles and skin are pushed and pulled. You also see this movement through your eyes. Your brain receives these matching signals and decides that you are moving.

When the car continues to move you stop feeling this movement as your body moves with the car and the cells in your ears, muscles and skin stop being pushed and pulled. But your eyes keep seeing that you are moving. Your brain now receives these mismatching signals and has to decide if you really are or are not moving. This indecision in the brain can lead to stress response in the body that can make some people feel sick.

Trying to match signals to the brain is behind some of the simpler things some people do to overcome their motion sickness. One example is to sit in the front seat of the car and look to the horizon. As the horizon doesn’t move, your eyes can be tricked into telling your brain that you’re not moving. This doesn’t work for everyone as some people’s brains are not so easily tricked.

AUTHOR: Associate Professor Wayne Wilson is the Head of Audiology at UQ's School of Health and Rehabilitation Sciences.
Wayne's current research interests include auditory processing and auditory processing disorder, auditory evoked potentials, and simulated learning environments.