By: Emil Lars

Updated: Apr 2022

Years ago, I took my first freediving course. Although a fairly experienced scuba diver at the time, equalization was a nightmare. I could dive down to 7 meters, but feet first. Headfirst was nearly impossible. I was using a technique called Valsalva. The Valsalva maneuver is performed by moderately forcing an exhalation with the nose pinched , a method that mainly uses the abdominal muscles which requires a lot of energy but  is very easy to learn and works well enough for scuba. Apparently, not so for freediving.

To determine if you are using Valsalva to equalize, firmly place one hand over the abdomen while pinching your nose, then equalize a few times. If your abdominal muscles tense up, then you are using Valsalva.

The strain caused by the abdominal muscles raises the pressure in the passages (trachea, larynx, mouth, nasal cavity) all the way to the eustachian tubes and into the middle ear. As you can imagine, much of the pressure goes to waste since it unnecessarily pressurizes all the air spaces. The pressure produced becomes too weak to open the eustachian tubes. Any minor inflammation, mucus or fluid build-up in the eustachian tubes makes them even harder to pressurize.

With the head down as we descend, air naturally “floats” back up into the lungs, away from the eustachian tubes, making it even harder to push down, adding to the difficulty. This explains why it is easier to equalize in upright position where the head is above the lungs. Unfortunately, this is not the position we are normally in when we freedive.

Equalization needs a pocket of air to work, the more the better.  This is one of the reasons why equalizing is easier on scuba, there’s plenty of air.  Because air is compressible under pressure, the volume of air inhaled just before a freedive becomes less and less as you go deeper, making equalization trickier as you descend.

In addition, freediving requires as minimal an effort as possible to conserve oxygen. The effort required to tense the abdominal muscles enough to equalize the middle ear is a lot. Valsalva is simply ineffective for freediving.

Curious to see if I could freedive deeper, I went off to find more information on equalization.  There was only one document on Frenzel equalization that existed at the time and it had outdated and very limited information, but it was enough to learn from.  It took me a very long time to learn; but with proper instruction, and with a lot of resources online now, it’s not uncommon for students to pick it up after a couple of days, overnight, or even within a day if you’re willing to put in the time and work. No one can do it for you.

Frenzel is a much better equalization method in many ways particularly in freediving where energy conservation is critical.  It doesn’t require much effort at all once mastered and is the foundation for the more advanced equalization method used in even deeper freediving.

Frenzel requires good control over certain muscles – the glottis, soft palate, tongue, and larynx.  While some do it naturally, some will have to learn.  Tricky enough in the beginning, but it can be learned.  Some pick it up faster than others, but it can be mastered by anyone.

The Frenzel Technique

In Frenzel, the movement of the tongue or the larynx compresses the trapped air inside the mouth and the nasal cavity.  The pressure forces the air to enter the nasal cavity and tries to escape out the nose, but the nostrils are pinched shut.  Air cannot escape back into the lungs because the glottis is closed.  Air cannot escape out the mouth because the tongue applies an airtight seal either against the upper teeth or in the back of the mouth.  Nowhere else to go, the air enters the eustachian tubes and into the middle ear equalizing the pressure.

The 4 elements to performing Frenzel

The first element is to have a closed glottis.  Where and what is glottis?  Glottis is the opening between the vocal cords in the throat.  You can make the “aahhh” sound and by stopping the sound, with your mouth open, you are closing your glottis.  You can also try inhaling fully through the mouth and then while keeping the mouth open, hold the air in the lungs by closing the glottis.  Super easy!

The 2nd element?  Soft palate in the neutral position.  The soft palate is the soft fleshy part toward the back of the roof of the mouth.  If you drew a line with your finger from the back of your upper teeth to the back until you start to gag, that’s where the soft palate is.  Inhale big and with an open mouth, exhale very slowly out the nose, then mouth, then nose again and keep switching until you run out of air to exhale.  Every time you switch between the nose and the mouth, the part that you feel you’re raising and lowering is the soft palate.

How do we determine if the soft palate is in the neutral position?  It is when you can exhale out the nose and the mouth at the same time. We can do it very easily.  It is normally in a neutral position. If the back of the throat feels relaxed, it is in the neutral. When you tense the throat, the tendency is to raise the soft palate. This is why relaxation plays a big factor in equalization.

As you’ve noticed, controlling the glottis and the soft palate is not at all difficult.  We do it all the time whenever we talk – whenever we make oral and nasal sounds!  What’s difficult is controlling them together.  Like paired muscles, you will likely raise your soft palate when you close your glottis.  But we need to have the soft palate in the neutral position.  Try this: inhale fully through the mouth and then, with the mouth open, hold the air in the lungs by closing the glottis (while keeping the abdominal muscles relaxed).  While holding the air with closed glottis, play with raising and lowering (relaxing) the soft palate.  Remember how soft palate in the neutral position feels like – it feels the most relaxed and natural so that makes it a bit easier.

The 3rd element is you need to be able to trap some air between the tongue and the roof of the mouth by performing a tongue block or a seal.  While there are several seals that you can use, let’s use the “n”. With the nose pinched, try to say the letter “n”.  You might already feel a slight pressure in the nasal cavity because making the “n” sound, being nasal, puts the soft palate in the open position. Now we just need to amplify this pressure by maintaining that tongue seal and pushing up the tongue (or larynx).

The last element being you need to be able to repeatedly push up or pump the tongue (or larynx) while keeping the tongue seal and the glottis closed. It may feel very much like you are pumping the tongue because perhaps it is that action that pulls the the larynx as opposed to the muscles surrounding the larynx doing the pumping.  The tongue is a big and powerful muscle after all. The experts have yet to agree about this.

Putting everything together

With the nose pinched, and while maintaining the natural tongue seal created by saying the letter “n”, slowly and consciously engage the tongue (or the larynx) to compress the trapped air above it. If pressure does not build up or the eustachian tubes do not equalize, check to make sure that the glottis is closed.

Give it a few tries. Assuming that the glottis is closed, and because the soft palate will already be in the neutral position with the “n” seal, the added pressure created by engaging the tongue (or the larynx) should equalize the eustachian tubes.

Did you feel your ears pop? If not, it’s totally ok. It doesn’t always work the first time, sometimes it takes a whole lot of practice. After all, we don’t normally use these muscles together for this purpose. Let’s read on…

Possible problems

• Pressurized air escapes down the throat instead of up the eustachian tubes due to open glottis.
• Pressurized air cannot get to the nasal cavity due to raised soft palate.  Recall how the soft palate feels in the relaxed position.
• Pumping the tongue (or larynx) does not create pressure due to the tongue not having a good seal all around.  Without an airtight seal, all you’re doing is aimlessly moving the tongue in the air space inside the mouth.
• No bubble of air is left to compress between the tongue and the roof of the mouth.  Keep in mind that once the tongue touches the roof of the mouth, you will no longer be able to equalize (as there isn’t anything to compress) until you you move a bubble of air in between again. Break the tongue seal to let a pocket of air in from the lungs to the mouth.
• An important matter that is often neglected in understanding equalization is relaxation. When we tense up, equalization becomes difficult and even impossible. We tend to tense up when we aren’t comfortable during a dive. When you’re not ready or prepared for the dive, unable to relax through the descent, having early contractions, maybe feeling tired, anxious, or stressed, equalization suffers greatly. Tension causes us to raise the soft palate. The blockage makes it impossible to pump air into the eustachian tubes. It takes a certain level of awareness to realize this on a dive, but it is important to understand that a lot of equalization issues are due to tension. Eliminate the potential causes of stress and tension on a dive.

Practice Tips

• Practice with your head down to simulate a normal freedive position.  Lie belly down on a bed, table, or any structure that can safely support your body, or with your head down either from sitting or standing position.
• Once your Frenzel is more consistent, practice letting a small amount of air escape every time you equalize to simulate the decreasing volume of air. You can do this by pinching the nostrils lightly.  You will have to shift a pocket of air from the lungs to the mouth each time you equalize.
• Do it 500 more times after you think you get it as it needs to be mastered before taking it in the water.  Simply understanding how it works or by being able to do it a few times just doesn’t cut it.  Being in an inverted position underwater, plus the many added distractions in the water, make it even harder to perform Frenzel if you have yet to master it.  Fortunately enough, it’s easy to find time to practice – while watching TV, reading a book or even while working in front of a computer.