Equalization Techniques: Mastering Pressure Changes

What Happens to Your Ears at Depth

The middle ear is an air-filled space behind the eardrum, connected to the throat by the Eustachian tube — a narrow passage that normally opens briefly when you swallow or yawn to equalise pressure with the outside world. On the surface, this process is invisible and automatic. Underwater, as pressure increases with depth (1 bar per 10 metres), the outside pressure rapidly exceeds the pressure inside the middle ear, pressing the eardrum inward. Without equalisation, this causes pain, then barotrauma — a squeeze or rupture of the eardrum.

The eardrum can rupture at relatively shallow depths (3–4 metres) in divers who continue to descend through ear pain rather than stopping. A ruptured eardrum admits cold water to the middle ear, causing sudden violent vertigo — a dangerous situation at depth.

The Valsalva Maneuver — and Its Limits

Every diver learns the Valsalva maneuver in their open water course: pinch the nostrils and blow gently against the obstruction. This increases the pressure in the nasopharynx, which pushes the Eustachian tube open and allows air to flow into the middle ear.

The Valsalva works — but it has a significant flaw. It only works when the Eustachian tube is not already swollen or obstructed. If you descend until you feel pain and then attempt Valsalva, the tube is already deformed by the pressure differential and opening it requires more force than is safe. Equalise early and often — before you feel discomfort.

The frequency: every 0.5–1 metre of descent, especially in the first 5 metres where the pressure change per unit depth is greatest.

Better Techniques

The Toynbee Maneuver: Pinch the nose and swallow simultaneously. Swallowing opens the Eustachian tube from the throat end; the pressure from pinching closes the nostrils. Gentler than Valsalva and less likely to cause barotrauma if done too forcefully.

The Frenzel Maneuver: Close the glottis (the vocal cords — hold a grunt) and use the back of your tongue to pressurise the nasopharynx, like making a 'K' or 'G' sound, while pinching the nose. This is the technique used by competitive freedivers and experienced scuba divers — faster, lower pressure, and possible with a mouthpiece in. It takes practice to isolate the tongue from the jaw.

The Edmonds Technique: Combine a jaw jut (pushing the lower jaw forward, which opens the Eustachian tubes mechanically) with a Valsalva. Useful for divers who find Valsalva unreliable.

Swallowing and yawning: Simply swallowing or yawning opens the Eustachian tube passively. Some divers can equalise entirely by swallowing; this is the most natural approach but the least powerful.

Descent Technique for Difficult Equalizers

1. Descend feet-first rather than head-first — the upright position is slightly easier for equalisation
2. Equalise before you feel pressure — not in response to it
3. If you cannot equalise at a given depth, ascend 1–2 metres and try again from a lower pressure differential
4. Never continue past pain. Discomfort is a warning; pain is a stop signal.

When Equalisation Fails: Causes

• Congestion from a cold, allergy, or sinus infection: Swollen Eustachian tubes cannot be forced open safely. Do not dive with active congestion. Decongestants (e.g., pseudoephedrine) can help but wear off at depth — rebound congestion can trap air in the middle ear during ascent, causing reverse squeeze.
• Caffeine and alcohol: Both can cause Eustachian tube inflammation. Avoid the night before a day of frequent descents.
• Horizontal position: Head-down descent is harder to equalise. A controlled vertical or head-up descent gives more time to equalise before depth accumulates.

Sinus Equalisation

The sinus spaces (frontal, maxillary, ethmoid) normally equalise passively through small openings into the nasal cavity. Congestion can obstruct these openings, causing sinus squeeze — pressure-induced pain in the forehead and cheekbones. Unlike the middle ear, there is no active technique for sinus equalisation — if the openings are blocked, the only solution is to ascend until the pressure differential is small enough to manage.

Chronic sinus problems and nasal polyps predispose divers to sinus squeeze and warrant evaluation by an ENT physician if they recur.