Dumagat Freedive International Freediving School

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Frenzel Equalization: The Definitive Guide

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 mouth and nose closed, a method that mainly uses the abdominal muscles which requires a lot of energy but  is very easy to learn and works well for scuba. Apparently, not so for freediving.

To determine if you are using Valsalva to equalize, place one hand over the abdomen while pinching your nose and with a closed mouth, 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 of 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, farther away from the eustachian tubes, making it even harder to push it 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  There was only one document on Frenzel equalization that existed at the time and it had outdated and very limited information, but it was enough to learn from.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 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.

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.  When you close your glottis, you will likely raise your soft palate.  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 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.  Try to say the letter “t” without making the sound.  Remember: there must be some air trapped between the tongue and under the roof of the mouth.  Doesn’t get any easier than that!

The last being you need to be able to pump the larynx up and down (while keeping the throat and tongue blocks) to pressurize and force the air up the eustachian tubes. It will feel very much like you are pumping the back of your tongue because perhaps it is that action that pulls the muscles in the larynx as opposed to the muscles surrounding the larynx doing the pumping.  The experts have yet to agree about this.


It is also possible to perform Frenzel using the “k” block instead of the tongue or “t” block.  Try to say “ka” without making the sound.  By sealing the opening between the tongue and the soft palate, you can lock the air in.  And then by pumping the back of the tongue, you can pressurize the trapped air to equalize.  Practice with the mouth open and with the tip of the tongue in a relaxed position.

You can also say the letter “n” to make a tight seal between the tongue and the roof of the mouth.  And like in the “t” or “k” blocks, make sure to always trap a bubble of air.  As you begin to master these blocks, you should be able to consistently move air from the lungs to the mouth, between the tongue and the roof of the mouth.

Putting everything together

With the nose pinched, perform a tongue block (whether with “t,”  “k,” or “n”) with a big bubble of air trapped between the tongue and the roof of the mouth, close the glottis then pump the tongue. Did you feel your ears pop?  It might take a few or even many tries, but if you feel you’re missing something, 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 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.
  • 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 with 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, with your head down hanging from the waist.
  • Pinch the nose lightly to let a small amount of air escape every time you equalize to simulate the decreasing volume of air.  Practice moving air from the lungs to the mouth as you run out of air to equalize with.
  • 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 while lying in bed.

Final words

No amount of time reading another article or watching yet another YouTube video will enable you to master the technique if you’re not willing to do the work. There are many stories of students paying top money to learn from equalization experts only to be disappointed for not getting the skills that they thought they had paid for. Like these experts, I continue to have students who want to learn, but don’t seem to want to do the work. Without question, equalization courses from true experts like Andrea Zuccari, Federico Mana, and others of the same caliber are some of the best investments you will ever make in your freediving journey. I would recommend you look them up and consider learning from them if you can. Instructors can only do so much in helping you learn to equalize, the rest is up to you. There is no instant gratification in learning Frenzel, but I assure you that it will feel like magic when you finally get it. Practice, practice, practice and you will.

Hope you enjoyed reading this and found it to be helpful. Please follow our Instagram @dumagatfreedive or like our Facebook page. Much appreciated. Thank you.


Eric Fattah. (2006). Frenzel-Fattah Equalizing Workshop: Step-by-step Guide to Optimal Equalizing for Freedivers and Scuba Divers. Retrieved July 2013, from http://liquivision.com.

Special thanks to Andrea Zuccari for debunking a widely accepted equalization myth and for pointing out an earlier error, and Linda Paganelli for driving the discussion leading up to its correction.

Also thanks to Adam Stern for his recent MRI equalization video.


This article is geared towards providing beginner to intermediate freedivers an easy, user-friendly and practical way to learn, and understand the Frenzel equalization technique. The information herein is offered solely as informational and not intended as a substitute for instruction from equalization experts or from attending a formal freediving course. Freediving and breath-holding can be dangerous if practiced without proper knowledge and education. They should be practiced with a trained buddy or a qualified instructor. Attend a formal freediving course.

By: Emil Lars

Author: Dumagat Freedive International Freediving School

Learn and experience freediving in Dauin with the country’s most experienced and longest-tenured professional freediving instructor. Dumagat Freedive is a locally operated professional freediving center in the Philippines. The center offers courses from beginner to instructor levels. Formerly situated on the island of Romblon, it has since moved to Dauin in Negros Oriental. The center delivers personalized freediving education using SSI’s world-class training methods, materials, and standards. Come and see us for your next freediving adventure!

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