Equalizing in freediving – why does it sometimes fail?

1. What actually happens in your ears?

As you descend, the surrounding pressure rises. At a water depth of ten metres it is already about twice as high as at the surface.

Your middle ear is a small, air-filled space behind the eardrum. Through the Eustachian tube it is connected to the nasopharynx.

During descent, additional air has to reach the middle ear so that the pressure stays balanced on both sides of the eardrum.

If that does not happen, the eardrum is pulled inward. First there is a feeling of pressure; later, pain and injury can follow.

Worth knowing: the greatest relative pressure change happens near the surface. That is why equalization is especially important in the first metres.

DAN points out that a middle-ear barotrauma can occur at a depth of only one to three metres.

2. Frenzel or Valsalva – what is the difference?

Many people first learn the Valsalva technique: pinch the nose and gently try to exhale through the nose.

The pressure is produced mainly by the breathing muscles.

The Frenzel manoeuvre works differently. The back of the tongue acts like a small piston and compresses air in the nasopharynx, while the glottis stays closed.

That makes it possible to create pressure more precisely, without exhaling forcefully from the lungs.

That is especially relevant in freediving, because lung volume becomes smaller as depth increases.

But does that mean Frenzel is scientifically proven to be always better?

Not quite.

A study of middle-ear function in freedivers showed that experienced divers used Frenzel more often. In the group that was studied, stronger pressure injuries were more often associated with Valsalva. That does not, however, prove a general superiority for every diver.

The most important technique is the one with which you can equalize early, in control and without force.

3. Why does equalization sometimes fail?

You may know this: yesterday everything worked. Today one ear suddenly stays closed.

There are several possible causes.

Even a mild cold or an allergy can make the mucous membranes swell. The Eustachian tube may then no longer open as easily.

Anatomical differences, earlier ear problems or an unsuitable technique can play a part too.

And sometimes the problem simply begins because you equalize too late.

When the pressure difference between the middle ear and the surroundings becomes too large, opening the Eustachian tube can become increasingly difficult.

More force does not necessarily help then – quite the opposite.

An interesting study examined freedivers during repeated training sessions. In 48% of the ears examined, mild to moderate pressure-related changes were found. These changes increased as the number of training sessions increased.

That does not mean that 48% of all freedivers suffer a clinically relevant ear injury. It does show, however, that repeated pressure exposure can cause changes even when not every dive feels like a problem.

4. Why you should never equalize by force

A common misunderstanding in freediving is this: if equalization does not work, you simply have to push a little harder.

That is exactly what can become dangerous.

A forced equalization can injure the middle ear and, in some circumstances, even sensitive structures of the inner ear.

A forceful Valsalva manoeuvre when the Eustachian tube is already blocked is especially problematic.

Possible consequences are middle-ear barotrauma, eardrum injuries and, in severe cases, inner-ear damage.

So this applies:

Pain is not a sign that you are getting used to the depth. It is a warning signal.

If equalization does not succeed, you should stop the descent immediately. Ascending a little can reduce the pressure difference. If equalization still does not work, the dive is over.

If ear pain, reduced hearing, noises in the ear or dizziness continue after a dive, a prompt medical examination is needed. Sudden hearing loss or severe dizziness should be assessed urgently.