Lunch break. You stand in front of the mirror, yawn, swallow, move your jaw. No cracking. Only the clack of a toilet door can be heard. You’re holding your nose, and suddenly she’s standing next to you, the cleaning lady, armed with toilet cleaner and a sponge. You turn bright red.
She grins, “The Lowry method, isn’t it? I prefer the pressure equalization method that was introduced by this Italian in the 18th century. Or named after the German nosedive pilot guy. Sorry, I am terrible at remembering names.”
“Yes, with a cracking effect in your ear. If you start at an early stage just below the surface of the water, you will be able to keep the pressure balanced during your entire descent; you will not even get any earaches or a barotrauma.”
You have calmed down a little, your face is starting to relax: “Are you a hobby-diver?”
She begins: “Gas-filled hollows? Lung, gastrointestinal tract, middle ear? Totally unpractical under water! As the diving depth increases, the ambient pressure increases. No problem for your muscles, not so for air-filled body constructs. If the ambient pressure increases, gases are compressed and their volume is reduced. Pressure changes in the lungs, nasal sinuses, and the frontal sinus are automatically adjusted by continuous breathing of the compressed air via the respiratory regulator (2nd stage). Behind your diving mask and in case of your ears, this has to be done manually. Blow air into the diving mask via the nose: Done. And what about your ears? An elastic membrane, the eardrum, separates the outside and the inside. A great idea of nature: Penetration by water or foreign substances is prevented. The bad news: As the external pressure increases, the pain-sensitive separating layer is pushed inwards. The good news is that we have a special connection between the middle ear and the nose and throat region.”
You are also getting into it: »Eustachian tube, 3.5 cm long, lockable, can be opened by swallowing or yawning. When diving, wilful opening is possible: Hold your nose, take short, deep breaths with your mouth closed similar to blowing your nose. As a result, the pressure in the nasopharynx increases, the tube opens up, and you are done with pressure compensation.”
She continues: “Valsalva method. Alternatively, you can learn how to tighten certain pharynx muscles.”
Your phone rings. You point to the display, say: “Sorry, my boss! – Continue tomorrow? Same time, same place?”