Let’s review some basic dive physiology. Your middle ears are dead air spaces, connected to the outer world by the eustachian tubes running to the back of your throat. When you fail to increase the pressure in your middle ears to match the building pressure around you, the result is pain and potential damage to the delicate mechanisms of the ear. But you knew that already.
The key to safe equalizing is opening the normally closed eustachian tubes, allowing higher-pressure air from your throat to enter your middle ears. Most divers are taught to equalize by pinching their nose and blowing gently. Called the Valsalva Maneuver, it essentially forces the tubes open with air pressure.
The better way is to use the throat muscles to pull your eustachian tubes open the way nature intended — by swallowing. You already do this hundreds of times a day — just listen for that faint pop you hear about every other gulp. The rapid pressure changes of scuba diving, however, are more challenging. You need to help this process along.
Listen for the “pop.”
Before you even board the boat, make sure that when you swallow you hear a “pop” in both ears. This tells you both eustachian tubes are opening.
Several hours before the dive, begin gently equalizing your ears every few minutes. Chewing gum seems to help because it makes you swallow often.
Equalize at the surface.
Prepressurizing at the surface helps most divers get past the critical first few feet of descent. It may also inflate your eustachian tubes so they are slightly bigger. Not all medical authorities recommend this, however. The lesson here is to prepressurize only if it seems to help you, and to pressurize gently.
Descend feet first.
Studies have shown a Valsalva Maneuver requires 50 percent more force when you’re in a head-down position than head-up.
Extending your neck tends to open your eustachian tubes.
Use a descent line.
Pulling yourself down an anchor or mooring line helps control your descent rate more accurately. A line also helps you stop your descent quickly if you feel pressure.
Equalize often, trying to maintain a slight positive pressure in your middle ears. Don’t wait until you feel pressure or pain.
Stop if it hurts.
Your eustachian tubes are probably locked shut by pressure differential. Ascend a few feet and try equalizing again.
Some foods, including milk, can increase your mucus production.
Avoid tobacco and alcohol.
Both tobacco smoke and alcohol irritate your mucus membranes, promoting more mucus that can block your eustachian tubes.
Keep your mask clear.
Water up your nose can irritate your mucus membranes, which then produce more of the stuff that clogs.
Alternative Ear-Clearing Techniques
There are two other problems with the Valsalva Maneuver: It may not work if the tubes are already locked by a pressure differential, and it’s all too easy to blow hard enough to damage something. Divers who experience difficulty equalizing may find it helpful to master some alternative techniques.
With your nostrils pinched or blocked against your mask skirt, swallow. Swallowing pulls open your eustachian tubes while the movement of your tongue, with your nose closed, compresses air against them.
A combination of Valsalva and Toynbee: while closing your nostrils, blow and swallow at the same time.
While tensing the soft palate and throat muscles and pushing the jaw forward and down, do a Valsalva Maneuver.
Close your nostrils, and close the back of your throat as if straining to lift a weight. Then make the sound of the letter “K.” This forces the back of your tongue upwards, compressing air against the openings of your eustachian tubes.
Voluntary Tubal Opening.
Tense the muscles of the soft palate and the throat while pushing the jaw forward and down as if starting to yawn. These muscles pull the eustachian tubes open. This requires a lot of practice, but some divers can learn to control those muscles and hold their tubes open for continuous equalization.