Freediving 101

Mask squeeze is also called face squeeze. It occurs when air is compressed inside a freediver’s mask during descent, causing the mask to squeeze hard against their face. It happens usually because a freediver does not equalize their mask properly while descending.

The effects of mask squeeze are dependent upon descent. The deeper a freediver descends, the stronger the pressure (negative pressure) will be inside the mask. Putting air into the mask is an easy but also vital skill to prevent from such injury happens. A simple way to do is to loose your equalization fingers on your nose, opening your soft palate, and the air in your mouth will automatically run into the mask. In a deeper depth (30 meters above), you may need to push air inside the mask, and this is why it is recommended that freediver should use a low volume mask to save their precious air.

The type of injuries caused by mask squeeze can range from superficial pressure marks on the face where the mask has tightened, through to swelling or bruising on the face and red spots or bloodshot eyes. It is not deadly but it is strongly advised to see a doctor to confirm your situation especially if your vision is affected.

A freediving wetsuit hood is meant to protect your neck from sun burn as well as to keep your head warm, reducing heat loss. However, this design could cause hood squeeze, which is when the air is trapped in a freediver’s outer ear by the hood of their wetsuits.

It is dangerous to have these extra air stock in the ear canal because when a freediver descends and this volume reduces, the air will get compressed and will pull the eardrum outwards causing pain. If this happens, immediately return to the surface. To avoid having air trapped in the outer ear canal, allow water into your hood by your ears prior to every dive. Or, pinch tiny pinholes in the side of the hood by your ears to let the water in before wearing it. The small holes would allow water to enter your ear canal while descending.

Warming: DO NOT lift your hood off your ears while the hood squeeze happens during descending to prevent from eardrum barotrama.

The barotrauma that is produced when the sinuses are not cleared can cause blood vessels in the lining of the nose to burst. This is sinus squeeze, which often occurs in freedivers who are diving with congestion because of a cold, dry air, irritants and allergies. The sinuses are a system of hollow cavities found within the skull. A total of four pairs of sinuses can be found within the head, behind the cheeks and nose and behind the forehead just above the eyebrows.

Sinus squeeze is caused by being unable to equalize the pressure inside any of the four pairs of sinuses. While descending, pressure builds up in the hollow cavities of freedivers’ sinuses. If a freediver is unable to equalize that pressure buildup, then a vacuum can develop within the sinus cavity, which results in intense pain or pressure in the forehead, teeth, cheeks, or eyes, and may cause the nose to bleed.

If experiencing a sinus block, stop your descent immediately by holding on to the guide rope and try to equalize again. If the pain does not go away, you should abort the dive and ascent in a controlled manner. A simple way to avoid a sinus block is DO NOT dive with a cold or congestion.

If a freediver misses an equalization or does not abort their descents past the point of pain immediately when their equalization fails, the eardrum can become perforated. The injury can range from a small hole to a sizable tear in the thin tissue that separates your ear canal from your middle ear. Perforated ear drum refers to a small pinhole in the eardrum while a large tear or a burst eardrum is called a rupture.

An eardrum perforation or rupture manifests itself with sudden, sharp pain in your ear, pus or blood drainage from the ear, hearing loss, noise in the ear (tinnitus), or vertigo. If the eardrum is damaged, there will also be a temporary loss of hearing to a certain extent. Sometimes a perforated eardrum can be recognized by bubbles coming out of the ear while a freediver is equalizing underwater. As a consequence of an eardrum injury, water will enter a freediver’s middle ear, causing dizziness and infection.

 If you suspect you have perforated or ruptured ear drum, you should immediately see a doctor and to stay dry for as long as the doctor recommends to avoid infeciton.

If a freediver fails to equalize and does not stop their descends, blood and other fluids might be forced into a middle ear, partially or even completely filling it. This is middle ear squeeze, which can be felt immediately after a dive, but might be felt a day later. A middle ear barotrauma causes sharp, sometimes extreme pain that might persist for days.

Upon descent, if your ear canal is blocked by a tight hood, a glob of wax or a non-vented ear plug, it becomes another dead air space that can’t equalize. Also, if there is an obstruction in the Eustachian tube such as from a cold, allergies, or having poor equalization technique in general, a freediver may be unable to achieve equalization. These situations create a vacuum in the middle ear space, which strengthens as pressure increases, causing the eardrum to bulge inward, swollen tissues, and a leakage of fluid and blood in the middle ear. Descending further may cause a ruptured eardrum. 

This can cause a feeling of fullness in the ear, similar to feeling as if you cannot get water out of your ear, along with muffled hearing or hearing loss. If you suspect you have perforated or ruptured ear drum, you should immediately see a doctor and to stay out of the water for as long as the doctor recommends to prevent infections or pressure changes.

Trachea squeeze usually happens to more advanced or competitive freedivers and can happen for a couple of reasons including not being well adapted to the depth, having strong contractions at depth, or a poor equalization technique. It is commonly caused by extending the neck at deep depths, whether it is looking for the bottom weight at the end of the guide rope on descent or looking up to the surface on ascent.

The symptoms of Trachea squeeze are coughing on surfacing, blood in the sputum, dark red in color, blood from the lungs is pink and sometimes frothy. The trachea is the tube running down our throats, which is comprised of cartilage rings that hold the trachea open. If the negative pressure goes too high, blood vessels along the walls of the trachea can rupture and when coming up, a freediver will then have the urge to cough, spitting up blood with their saliva.

If you see blood in your sputum, feel a tickle in your throat, or feel the urge to cough when you take a full inhale (and a lung squeeze has been ruled out), you may need to seek medical support or rest for few days.

To prevent trachea squeeze, you should always dive within your limits, avoid having big contractions down at depth, not do any hasty movements down at depth, and never tilt your head at depth.
Reference: Here.

Lung squeeze is a potentially fatal injury and is a serious injury in any case, needing to be properly treated with the support of a specialized medical doctor. It is most often caused by diving below residual lung volume (RV), usually between 30-45m (98-147ft), and keeping on descending further without being ready for it; in Scuba diving, however, lung squeeze is often caused by breath holding on ascent.

Through the injury of lung tissue, fluid is forced into the airspace of the lungs in order to equalise the negative pressure. Any liquid in the airspace of the lungs makes the gas exchange difficult or impossible, leading to drawn.Symptoms of a lung squeeze can include chest pain, shortness of breath, wheezing, the sensation of fluid in the lungs, fatigue, coughing, faintness, dizziness, weakness, and nausea. The freediver might cough up blood or pink foam, be disorientated, lose consciousness, or go into cardio-respiratory arrest. This can eventually lead to death. 

If a freediver has a flexible ribcage and diaphragm, good posture, a strong blood shift, avoids jerky movements or stretching out at depth, stays relaxed, stop diving if stressed or cold (shivering), and dives conservatively with slow progression, lung squeezes can be avoided. When diving deep you have to be very careful that you’re not diving too deep, too fast. Always get used to the depth and never dive beyond 3 meters of the previous depth you were comfortable at.

A reverse block is a tough situation. Normally, pressure must be released from middle ear as ascend, or the expanding air will bulge and even break your eardrums.

Normally, expanding air escapes down your Eustachian tubes, but if the tubes are blocked with mucus at depth (usually the result of poor equalization on descent, diving with a cold or relying on decongestants that wear off at depth), barotrauma can result. The expanding air inside your middle ear cannot then escape down the back of your throat. As a result, your eardrums bend outwards, and if the pressure is not released then your eardrum will rupture.

If this happens, immediately stop your ascent and hold onto the guide rope. Ascend as slowly as your air supply allows. Pointing the affected ear toward the bottom may also help. Otherwise, you will just have to endure the pain to reach the surface. If this doesn’t work and you are running out of air, then come straight to the surface, as it is better to have a problem at the surface than at depth.

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Will be updated soon.

Will be updated soon.