why we may feel pain when we travel on an aeroplane？ 10分

Some people experience ear pain when flying in a plane. Usually this happens as the plane descends to land. The pain is worse the lower the plane gets and can be quite severe on landing.

The pain is usually caused by unequal pressure that develops between the air in the middle ear and the air outside the ear.

The small space in the middle ear behind the eardrum is normally filled with air. This air space is connected to the back of the nose by a tiny channel called the Eustachian tube. The air on either side of the eardrum should be at the same pressure. As a plane descends the air pressure becomes higher nearer the ground. This pushes the eardrum inwards which can be painful. To relieve this, the pressure inside the middle ear has to rise quickly too. Air needs to travel up the Eustachian tube into the middle ear to equalise the pressure.

The Eustachian tube is normally closed but opens from time to time when we swallow, yawn or chew. In most people, just normal swallowing and chewing quickly causes air to travel up the Eustachian tube to equalise the pressure. Some airlines offer sweets to suck and eat when the plane is descending to encourage you to chew and swallow.

However, the Eustachian tube in some people does not open as easily and so the pressure may not be equalised so quickly. For example, some people may have a more narrow Eustachian tube than normal. Also, if you have any condition that causes a blockage to the Eustachian tube, then the air cannot travel up to the middle ear. The common cause of a blocked Eustachian tube is from mucus and inflammation that occur with colds, throat infections, hay fever, etc. In fact, any condition causing extra mucus in the back of the nose can cause this problem.

Ideally, anyone with a cold, respiratory infection, ear infection, etc, should not fly. However, not many people will cancel their holiday trips for this reason. The following may help people who develop ear pain when flying.

Suck sweets when the plane begins to descend. Air is more likely to flow up the Eustachian tube if you swallow, yawn or chew. For babies, it is a good idea to feed them or give them a drink at the time of descent to encourage them to swallow.
Try to take a breath in. Then, try to breathe out gently with your mouth closed and pinching your nose (the Valsalva manoeuvre). In this way, no air is blown out but you are gently pushing air into the Eustachian tube. If you do this you may feel your ears go 'pop' as air is pushed into the middle ear. This often cures the problem. Repeat this every few minutes until landing - whenever you feel any discomfort in the ear.
Do not sleep when the plane is descending to land. If you are awake you can make sure that you suck and swallow to encourage air to get into the middle ear.