Equalising Techniques

Introduction

Are equalising problems holding you back? Can you equalise while descending slowly, feet first on a scuba but struggle if you try to freedive head first? Do you sometimes find your ears block up halfway through a day of spearfishing? If any of these sound familiar then read on. If you are one of those people for whom equalising ‘just happens’ perhaps you should go off and do whatever it is that naturally gifted people do with their time.

What is equalising

Equalising is necessary to maintain pressure balance between the middle ear airspace, the rest of the body and surrounding water. As the pressure in the rest of the body and surrounding water increases due to descent it is necessary to equalize this pressure by introducing additional air into the middle ear through the eustachian tube. As the eustachian tube is normally closed by soft tissue around the opening in the back of the throat it is typically necessary to actively blow air through to the middle ear in order to equalise.

If you ever have the strange sensation of hearing yourself speak inside your head, usually after yawning – your eustachian tubes are open and sound is travelling to your ears on the inside!

What are the consequences of not equalising?
If the middle ear is not equalised properly to the surrounding pressure a partial ‘vacuum’ develops. This ‘vacuum’ flexes the eardrum progressively inward and collapses the soft tissue around the opening of the eustachian tube causing a ‘lock’.

In divers who have poor equalising technique this ‘vacuum’ will also rupture tiny blood vessels within the wall of the middle ear and cause inflammation and swelling of the lining of the middle ear. The swelling further compromises their equalising ability (and may last for several days). If the pressure differential becomes too great the drum will rupture with potentially serious consequences.

The Good News

The good news is that almost all of us have normal eustachian function. Normal function means we equalise hundreds of times a day while talking, swallowing etc to compensate for air gradually absorbed into the lining of the middle ear and relatively slow changes in barometric pressure. Within the normal group there is a range from the naturally gifted to those with tighter or ‘sticky’ tubes, however with the right technique, training and by looking after our ears anyone with normal eustachian function should be able to equalise sufficiently to spearfish and freedive to recreational depths.

The techniques

There are three principal techniques used for equalising.

1. The Valsalva Manoeuvre: Hold your nose and blow.

This is the easiest technique to teach and so is generally the method taught to beginners. Unfortunately the Valsalva has a number of disadvantages:
• The entire chest/diaphragm is involved in generating pressure to equalise.
• The pressure generated is poor
• It cannot be done rapidly
• Risk of inner ear damage by round window rupture
• Unsuitable for deeper dives
• Effects on blood pressure
• Unsuitable for head down diving for people with less patent tubes.

2. BTV (Beance Tubaire Voluntaire) aka ‘Hands Free’

Referring to my earlier comment about hearing yourself speaking - if you have experienced that sensation, you were effectively carrying out the BTV. When equalising using BTV you are flexing muscles that are associated with the soft tissue around the opening of the eustachian tube and pulling the tube open. Yawning, jaw thrusting or swallowing will exercise these muscles and may initiate equalisation. A diver who has trained these muscles will be able to hold the tubes open for the duration of the descent; equalising hands free is great for relaxation and streamlining.
The disadvantages
• This is the most difficult method to teach as the muscles involved cannot be seen directly.
• Divers with ‘sticky’ eustachian tubes will find this technique difficult, particularly head down.
• Unsuitable for deeper dives
For more information on learning how to BTV see the links section at the bottom of the page.

3. The Frenzel Manoeuvre

This method uses pressure generated by the tongue acting as a piston to pressurize the nasopharyngeal area and force air into the eustachian tubes. Because the lungs are not involved, the chest/diaphragm can remain relaxed and equalising on deep dives (where the lungs are effectively collapsed) is possible. The tongue is capable of generating considerably more pressure than the diaphragm and can be flexed rapidly to equalise at short intervals. In practice this means that once this technique is mastered, virtually everyone with normal eustachian function will be able to equalise head down.

How to tell what technique you are using

The first step is to determine what method you are currently using to equalise. To differentiate between a Frenzel and a Valsalva simply hold your nose with one hand and place the other hand on your diaphragm. If your diaphragm muscles move/tense up when you equalise you are using the Valsalva manoeuvre.

Recommended technique
1. Equalise prior to the duck dive
2. Equalise immediately following the duck dive
3. Equalise regularly before you feel any discomfort
4. If you are not using the Frenzel already, learn it.

How to Frenzel

These are the steps for a Frenzel Manoeuvre:
1. Squeeze the nostrils closed
2. Close the epiglottis (automatically occurs if you hold your breath with mouth open or go to pick up a heavy object)
3. Place the soft palate in the neutral position (the neutral position is where you exhale and air goes out mouth and nose simultaneously – you may need to practise to figure out the feel of when it is the right position)
4. Seal the tongue against the roof of the mouth, tip touching the back of your upper teeth (as if to speak the letter ‘T’)
5. Flex the back of the tongue up and forward.
6. If you don’t get it right away don’t give up – it can take time to get it right. When you do get it right you will feel/see (in a mirror) your nose flare and you may feel your ears equalise. With practise you will rapidly learn how to clear crisply.

This article is reproduced with permission of NZ Spearo Magazine 2009 - By Fran Rose Re-publishing elsewhere is prohibited