Why Do You Get Motion Sickness?


So, you've just begun your road trip with some friends when you decide to read a book in the back seat. But after only moments of reading, you start feeling dizzy, fatigued and nauseous. Sound familiar? What you're experiencing is motion sickness. About one third of the population experiences it, with more than 66 per cent of people claiming to experience it only in extreme conditions. So how does it work?

When your eyes and inner ear are sending different signals to the brain you start to get disoriented. Since the vestibular system inside your ear contributes to balance and spatial orientation, the tiny hairs inside the canal detect the movement of a fluid inside it allowing you to orient yourself. If you lean to the side, the fluid moves and signals are sent to your brain to help you understand this. But oftentimes, in a car, on a boat, or in an IMAX theatre your vestibular system is transmitting a different signal from your other senses. In the case of your car, your eyes see that everything in the car is seemingly stationary, particularly when you stare at a book. But your ears feel the movement of the car. Conversely, in the IMAX theatre, your eyes see a lot of motion while your ear is experiencing very little movement at all. This mismatch of signals tells the brain something's wrong.

So why does it induce vomiting?

The leading theory suggests that, evolutionarily, if the input signals from your ears and eyes weren't matching, you'd likely ingested a neurotoxin. Neurotoxins are poisonous to nerve tissue, potentially resulting in muscle paralysis, a slowed heart rate, or a disruption in the development of the nerves tissue overall.

The easiest way to get rid of it? Throw up. This was a fairly useful and accurate system before the advent of technology and advanced transportation. Too bad the brain never got the memo.

Mitch Moffit