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What Happens to Hearing When You Go Down in Altitude?

If you've ever been on a plane, you probably remember something strange happening to your ears, both as the plane was taking off and as it was descending. It comes on as a feeling of pressure in the head -- maybe a dull buzzing sound -- and then the realization that the stewardess offering you peanuts sounds almost unintelligible, like a parent from a "Peanuts" cartoon. This warping of hearing happens as a result of the change in air pressure that occurs every time you move up or down through the Earth's atmosphere. Though going down in altitude often has the more dramatic effect, any rapid shift fundamentally affects the way we hear.

  1. The Middle Ear and the Eustachian Tube

    • The middle ear is a hollow space within the skull, separated from the outside by the eardrum. The Eustachian tube is a thin, membrane-lined tube that connects the middle ear to the back of the nose. The air within the middle ear is constantly being absorbed by the membrane of the Eustachian tube, and replenished by the air carried to it by the Eustachian tube from the nose. This cycling of air from the outside to the inside of the skull maintains consistent air pressure within and without.

    Air Pressure and Altitude

    • Air pressure is a measurement of the total weight of the air in the atmosphere at any given altitude. Because most of the molecules in the Earth's atmosphere accumulate toward the surface due to gravity, the weight of the atmosphere is heaviest closest to the ground. Therefore, when you go up in altitude, air pressure decreases; when you go down, it increases. Gradual shifts in air pressure, such as those that occur in activities like mountain climbing, may be dramatic, but happen gradually enough to allow the middle ear time to adjust the internal air pressure. Sudden shifts like airplane flight, however, make a very noticeable impact.

    How Rapid Altitude Shifts Impact Hearing

    • When the air pressure inside and outside the skull suddenly become significantly different, hearing becomes muffled, and discomfort looms. Hearing occurs through a several-step process. First, the eardrum registers vibrations in the air outside the skull; then, the middle ear translates them into mechanical vibrations of tissue. Finally, the inner ear turns those vibrations into nerve impulses to be interpreted by the brain. Air is the medium of sound. If the outside and inside of the skull contain significantly different air pressures, the sound from the outside will not translate well.

    How to Resolve the Discomfort

    • Every time you swallow, a small air bubble travels through your Eustachian tube and into your middle ear, causing a small popping sound. By deliberately swallowing frequently, or chewing gum or sucking on a mint (either of which will stimulate the reflex to swallow automatically), you can accelerate your middle ear's adjustment to rapidly shifting air pressure. Yawning works even better. You'll know your middle ear is adjusting when you hear the famous popping sound and notice your hearing once again becoming clear and crisp.

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