Most people know that the inner ear is responsible for informing the brain about head orientation and acceleration, and contributes to equilibrium. This is true, and the important thing is that the intern ear senses acceleration (changes in speed), but not speed itself.

The bit about equilibrium is true, but what is less known is that the visual clues represent about 80% of what the brain uses to maintain equilibrium ! If you want a simple demo, simply stand on your bed, with your eyes closed.

After a couple of seconds, you'll start to oscillate, and if you don't re-open your eyes, this can make you fall down - hence the idea of doing it on your bed. If the inner ear information was sole responsible for equilibrium, how could that be ?

The very cause of motion sickness is cerebral confusion when the visual clues from the eyes don't match with the orientation / acceleration clues from the inner ear.

This is also a serious challenges for astronauts, as the up / down information from the inner ear is not available. Click here to read more about visuo-motor coordination in space flight.

Below are a list of typical situations leading to such confusion, as well as tips to avoid it, or recover from it if it happens despite the tips. Note that not all of the tips are applicable if you're driving or flying the vehicle causing the motion sickness.

The most typical motions-sickenss situation is reading in a moving vehicle. The ear senses some acceleration, and bumps if the vehicle is an aircraft, but the eyes don't perceive any movement. This is even worse when travelling backwards.

A variant from the first one applies mostly to train (and business jets) is watching another passenger while discussing.

Any moving environment can lead to motion-sickness (doh ! what a definition), including: aircraft, trains, cars, boats, submarines, space-ships, but also roller-costers, some fitness machines, and many others.

As motion sickness results from inner-ear / eye information mismatch, the logical cure is to make the information match. If you read, stop, and look outside. If you discuss with someone, tell him / her that you don't feel well and need to look outside.

To give as many chances as possible to your brain to re-synchronize, concentrate on an object, as far as possible. Stop moving your head, and breath deeply. If you can have some fresh air, this helps as well.

It is not always possible to do it, typically if you're in a plane flying in clouds, in a boat cabin with no or limited outside view, or in a submarine (less likely, but can be).

The best you can do in that case is to deprive your brain from one of its information sources. Stop, don't put a knife in your ears ! Closing your eyes is a much better solution - except if you're yourself in control of the vehicle.

If you can't cure the cause of motion sickness, many medications and tricks are exist. Simply google "motion sickness cure", and you'll be served with thousands of possibilities.

I can't be of any help selecting one, as I'm not subject to motion sickness myself. Be very careful if you opt for a medicament, many of them have important side-effects. Some can be so strong that it's not possible to drive after taking them...

Any experience of feed-back on a technique, be it positive or negative, is welcome in comments !