HOW TO EQUALIZE
All methods for equalizing your ears are simply ways to open the lower ends of your Eustachian tubes, so air can enter.
Pinch Your Nose and Blow (Valsalva Maneuver)This is the method most divers learn: Pinch your nostrils (or close them against your mask skirt) and blow through your nose. The resulting overpressure in your throat usually forces air up your Eustachian tubes.
Equalizing “Clearing your ears”
Equalizing is one of the first skills a new diver learns, and for most people it eventually becomes instinctive. However, difficulties are common, and many people who stop diving cite an inability to equalize as the reason why.
First, it’s important to understand what equalizing is. It’s the process of introducing air from the back of the throat to the middle ear via the Eustachian tube so that the pressure inside the middle ear is balanced with the increase in surrounding pressure that occurs as a diver descends. The Eustachian tube is protected via a one-way valve called the Eustachian cushion, which must be opened in order to allow air to pass through. During training, divers are taught to do this using the Valsalva Maneuver. This involves pinching one’s nose and blowing gently, thereby forcing pressurized air from the back of the throat to open the Eustachian cushion and pass into the middle ear.
This method is only effective if you equalize every few feet before pain occurs. If your ears are in pain, your Eustachian cushions are already locked closed by the increase in surrounding pressure, and the pressurized air forced from the back of your throat by the Valsalva Maneuver is not strong enough to open them. In this case, you need to employ methods that use the throat muscles instead of air pressure to open the Eustachian cushion. These include swallowing and moving your jaw from side to side. If you still can’t equalize, ascend a few feet and try again. If equalizing is a persistent problem, descending on a line can help to control your descent, giving you the time to equalize almost consistently on your way to the bottom.
Swallowing—and various methods of equalizing—are all ways of opening the normally closed Eustachian tubes, reducing the pressure differential between the outer ear and inner ear. The safest clearing methods utilize the muscles of the throat to open the tubes. Unfortunately, the Valsalva maneuver that most divers are taught does not activate these muscles, but forces air from the throat into the Eustachian tubes.
That’s fine as long as the diver keeps the tubes open ahead of the exterior pressure changes. However, if a diver does not equalize early or often enough, the pressure differential can force the soft tissues together, closing the ends of the tubes. Forcing air against these soft tissues just locks them shut. No air gets to the middle ears, which do not equalize, so barotrauma results. Even worse, blowing too hard during a Valsalva maneuver can rupture the round and oval windows of the inner ear.