I have done a lot of studying of ear mechanics and equalization the last few months, and this study has lead me to the belief that there are a couple of ear equalization myths in freediving. I welcome your disagreement, agreements, and thoughts.
First off, let me preface this with the argument that there are major physical differences between equalizing ears when freediving and scuba. I believe non-realization of these differences is the reason for the myths.
First myth: “To equalize ears all we need to do is open the Eustachian tubes. In fact we would all be better off if our Eustachian tubes stayed open all the time.” The last sentence above is almost word for word from a freediving hunting legend.
In reality the Eustachian tubes are designed to function as a valve between the middle ear and the pharynx. It would be undesirable to have them open all the time and it would actually be counter productive in freediving. As a valve they are to be open at times and closed at others.
The Eustachian tube has 3 functions: ventilation, protection, & drainage. First lets take protection. The closure of the tube is the protection feature. It protects the inter ear from reflux of nasopharyngeal secretions and bacterial flora. In otherwords things that cause middle ear infection. So if the Eustachian tube did not close, a person would suffer more ear infections than normal.
The second, and what us divers think about the most, is ventilation. Ventilation is allowing air to flow to or from the middle ear so that pressure can match ambient pressure on the other side of the eardrum. Okay, before you write me off for saying dum ass stuff you learned 20 years ago, go a little further with me.
What the difference between the pressure in the lungs & pharynx and the outer side of the eardrum, first for a scuba diver and then a freediver? Well a scuba diver is breathing from an ambient adjusting air device, a regulator. Therefore there is little difference in the pressure and thus if the Eustachian tubes stayed open all the time equalization would occur by itself.
In freediving there is a difference between the pressure in the lungs & pharynx and the outer side of the eardrum (assuming your not at the surface). The volume of air in the lungs does decrease some due to ambient water pressure, which would help to equalize it some, but I believe the volume in the middle air is mostly unaffected by ambient water pressure due to the fact it is protected by bone and cartridge. Therefore voluntary Eustachian tube opening equalization techniques may work a little in freediving, but they are not nearly as effective as in scuba.
It is the adding of air pressure to the middle ear to equalize the pressure to the ambient pressure on the outside of the eardrum, that causes equalization. The only way to do this in freediving is to increase the pressure by the exhaling in the Valsalva maneuver or by the tongue in the Frenzel technique. If the Eustachian tubes did not close after the equalization technique, then we would have to keep the pressure up from the lungs or tongue the whole time we were at depth. The fact that they close is what allows us to relax and enjoy ourselves for a while at a particular depth.
On a side note the reason we generally do not have equalization problems during ascent is that Eustachian tubes usually open by themselves with pressure from the middle ear. As air pressure builds in the middle air it bleeds off through the Eustachian tubes into the pharynx. It is the pharynx end of the tube that closes, so the air pushing from middle ear opens up the tube much easier than pressure from the pharyngeal.
The other related myth is Middle-Ear Barotrauma, aka Reverse Squeeze, in freediving due to blockage on in the outer ear. They say a tight fitting hood my cause this. Well tell me all you European, Canadian, and other cold water divers who dive with hoods, have you ever had this during freediving?
In scuba with air pressure in the pharynx being so much greater, this can be a problem. The middle air is an enclosed air filled cavity, therefore in freediving, if there was an enclosed air filled cavity on the outside of the eardrum, the pressure on both sides of the drum would be closer to each other and it would not suck the eardrum out. In scuba an opening of the Eustachian tubes with air pressure much higher from the pharynx than an enclosed air filled cavity on the outer eardrum side, would create an outward bending of the eardrum.
So how does these truths help in freediving. Well first, a clearer mental realization of what we are doing should help our technique. Our goal is not just to open up the Eustachian tubes, but through the use of muscles, push air into the middle ear and increase its pressure to the ambient pressure on the outside of the eardrum.
Second, this is the one that will probably cause the most constructive controversy! Outer ear blockage, aka air filled cavity on the outer eardrum side, is beneficial to freediving. Forget all that you have read about this in the past, it only applies to scuba. As long as you don’t block the ear with something that could be pushed into the eardrum itself from water pressure, than the more blockage, the more the pressure will equal the middle ear and less equalization you will have to do.
Remember I said these are my opinions and you are free to argue. Sharing my theory or prediction wouldn’t be fun if I didn’t go out on a limb a little! Speaking of prediction, I predict that within 10 years many freedivers will be using rigid sealing ear cups to create an air filled cavity on the outside of their ears.
Merry Christmas,
Don
First off, let me preface this with the argument that there are major physical differences between equalizing ears when freediving and scuba. I believe non-realization of these differences is the reason for the myths.
First myth: “To equalize ears all we need to do is open the Eustachian tubes. In fact we would all be better off if our Eustachian tubes stayed open all the time.” The last sentence above is almost word for word from a freediving hunting legend.
In reality the Eustachian tubes are designed to function as a valve between the middle ear and the pharynx. It would be undesirable to have them open all the time and it would actually be counter productive in freediving. As a valve they are to be open at times and closed at others.
The Eustachian tube has 3 functions: ventilation, protection, & drainage. First lets take protection. The closure of the tube is the protection feature. It protects the inter ear from reflux of nasopharyngeal secretions and bacterial flora. In otherwords things that cause middle ear infection. So if the Eustachian tube did not close, a person would suffer more ear infections than normal.
The second, and what us divers think about the most, is ventilation. Ventilation is allowing air to flow to or from the middle ear so that pressure can match ambient pressure on the other side of the eardrum. Okay, before you write me off for saying dum ass stuff you learned 20 years ago, go a little further with me.
What the difference between the pressure in the lungs & pharynx and the outer side of the eardrum, first for a scuba diver and then a freediver? Well a scuba diver is breathing from an ambient adjusting air device, a regulator. Therefore there is little difference in the pressure and thus if the Eustachian tubes stayed open all the time equalization would occur by itself.
In freediving there is a difference between the pressure in the lungs & pharynx and the outer side of the eardrum (assuming your not at the surface). The volume of air in the lungs does decrease some due to ambient water pressure, which would help to equalize it some, but I believe the volume in the middle air is mostly unaffected by ambient water pressure due to the fact it is protected by bone and cartridge. Therefore voluntary Eustachian tube opening equalization techniques may work a little in freediving, but they are not nearly as effective as in scuba.
It is the adding of air pressure to the middle ear to equalize the pressure to the ambient pressure on the outside of the eardrum, that causes equalization. The only way to do this in freediving is to increase the pressure by the exhaling in the Valsalva maneuver or by the tongue in the Frenzel technique. If the Eustachian tubes did not close after the equalization technique, then we would have to keep the pressure up from the lungs or tongue the whole time we were at depth. The fact that they close is what allows us to relax and enjoy ourselves for a while at a particular depth.
On a side note the reason we generally do not have equalization problems during ascent is that Eustachian tubes usually open by themselves with pressure from the middle ear. As air pressure builds in the middle air it bleeds off through the Eustachian tubes into the pharynx. It is the pharynx end of the tube that closes, so the air pushing from middle ear opens up the tube much easier than pressure from the pharyngeal.
The other related myth is Middle-Ear Barotrauma, aka Reverse Squeeze, in freediving due to blockage on in the outer ear. They say a tight fitting hood my cause this. Well tell me all you European, Canadian, and other cold water divers who dive with hoods, have you ever had this during freediving?
In scuba with air pressure in the pharynx being so much greater, this can be a problem. The middle air is an enclosed air filled cavity, therefore in freediving, if there was an enclosed air filled cavity on the outside of the eardrum, the pressure on both sides of the drum would be closer to each other and it would not suck the eardrum out. In scuba an opening of the Eustachian tubes with air pressure much higher from the pharynx than an enclosed air filled cavity on the outer eardrum side, would create an outward bending of the eardrum.
So how does these truths help in freediving. Well first, a clearer mental realization of what we are doing should help our technique. Our goal is not just to open up the Eustachian tubes, but through the use of muscles, push air into the middle ear and increase its pressure to the ambient pressure on the outside of the eardrum.
Second, this is the one that will probably cause the most constructive controversy! Outer ear blockage, aka air filled cavity on the outer eardrum side, is beneficial to freediving. Forget all that you have read about this in the past, it only applies to scuba. As long as you don’t block the ear with something that could be pushed into the eardrum itself from water pressure, than the more blockage, the more the pressure will equal the middle ear and less equalization you will have to do.
Remember I said these are my opinions and you are free to argue. Sharing my theory or prediction wouldn’t be fun if I didn’t go out on a limb a little! Speaking of prediction, I predict that within 10 years many freedivers will be using rigid sealing ear cups to create an air filled cavity on the outside of their ears.
Merry Christmas,
Don
