Re: why does chewing gum help equate pressure on the ear during a plane flight?

Hi Jeff -
The act of swallowing contracts muscles in the area of the pharynx (throat) that cause the Eustachian tube to open briefly. Yawning also does the same thing. Chewing gum generates saliva, which will lead to swallowing. Thus, when flying a plane you have the option of chewing gum (and swallowing), or forcing yourself to yawn to help equalize the pressure.

The Eustachian tube runs from the pharynx to the middle ear. It is the only direct connection to help equalize pressure between the outer and middle ear, or to drain fluids in the middle ear from infection or other causes. Next time you yawn listen for the characteristic "pop" that occurs during yawning -- that will be your Eustacian tubes opening.

In a case where ambient pressure drops rapidly (as in flying a plane, even in a pressurized cabin), opening of the Eustacian tube lets air out of the higher-pressure middle ear into the now lower-pressure pharynx. Likewise, if pressure outside is greater than pressure in the middle ear, opening of the tube lets air in to equalize the differential. The flow is simply based on high pressure -> low pressure.

Hope this helps..

-L. Bry, MadSci Admin