Barotrauma and equalizing: ears, sinuses, mask and lungs

Halfway down the descent line, your right ear starts to hurt. Blowing harder won’t clear it: stop, go up a little and try again gently. This page covers your ears, sinuses, mask and lungs, and the breathing rule that protects your lungs on the way up.

What is barotrauma?

Barotrauma is a pressure injury to an air space: your ears, sinuses, mask or lungs, squeezed on the way down or overexpanded on the way up. Ear barotrauma is the most common diving injury, according to DAN Europe, and DAN reports that nearly half the calls to its emergency hotline concern ears.

Why do the first meters matter most?

In proportion, pressure changes fastest near the surface. In seawater, every 10 m (33 ft) adds 1 bar (1 atm). Between the surface and 10 m (33 ft), the absolute pressure doubles, so an air space halves in volume; from 10 to 20 m (33 to 66 ft), the pressure only rises by half. That’s Boyle’s law.

Drag the depth: Boyle’s law in action

0 m

Depth010 m20 m30 m40 m

How do you equalize your ears?

You equalize by sending air up the Eustachian tubes into your middle ears, before you feel pressure.

1. Start at the surface, before you go under.
2. Pinch your nose and blow gently against it. Never hard.
3. Swallow or move your jaw, alone or while blowing.
4. Go down feet first and look up: it helps the tubes open.
5. Equalize again and again on the way down. DAN Europe suggests every 0.3 to 0.5 m (1 to 1.6 ft) early in the dive.

What should you do if your ears won’t equalize?

Stop descending, signal your buddy and go up a little until the discomfort eases, then try again gently. If it still won’t clear, end the dive. Forcing it can damage the inner ear, with hearing loss, ringing or vertigo, sometimes for good.

Don’t dive with a cold, allergies or a blocked nose. A decongestant can wear off at depth and trap air on the way up: that’s a reverse block, felt as pressure or pain while ascending. Stop, go down slightly, swallow or move your jaw, and come up more slowly. And never wear ordinary earplugs: they trap an air space you can’t equalize.

Try a question from the app

an ear that won’t clear

At 5 m (15 ft), your right ear won’t clear and starts to hurt. What do you do?

1. ABlow harder against your pinched nose until it pops
2. BKeep descending slowly: it often clears by itself
3. CSignal your buddy, go up a little and try again gently
4. DSwim straight up to the surface alone and end the dive

Show the answer

Answer C. Going up a little reduces the pressure difference; then you can try again gently. Blowing hard or continuing down risks injuring your ear. Leaving your buddy creates a new problem.

How do you prevent a sinus or mask squeeze?

Your sinuses equalize on their own while your nose is clear. Congestion blocks them, with pain above the eyes, in the cheeks or upper teeth, sometimes a nosebleed: don’t dive congested.

Your mask is an air space too. Breathe out gently through your nose into it each time you equalize your ears, as DAN suggests; that’s why swimming goggles won’t do. A mask squeeze usually leaves bruising or red eyes, but eye pain or any change in vision needs a doctor right away.

Why must you never hold your breath on scuba?

Because the air in your lungs expands as you rise: hold your breath on the way up and your full lungs can tear. DAN calls this pulmonary barotrauma: it can send gas bubbles into the arteries (arterial gas embolism, the more serious form of decompression illness), or let air leak around a lung (pneumothorax) or into the chest and under the skin.

It doesn’t take a deep dive: the UHMS says a breath-hold ascent of as little as 1 m (3 ft) can be enough, which is why “shallow water can’t hurt your lungs” is one of the dive theory myths. So:

• breathe slowly and continuously, without pausing at the top of a breath;
• whenever the regulator is out of your mouth, exhale a thin stream of small bubbles;
• ascend slowly, and take the most care in the last few meters (feet).

Try a question from the app

why breath-holding is dangerous

What is the main danger of holding your breath while ascending on scuba?

1. AYour body absorbs too much nitrogen
2. BThe air in your lungs expands and can tear them
3. CYou float up too fast to control your ascent
4. DCarbon dioxide builds up in your blood and you black out

Show the answer

Answer B. Lungs full of compressed air can’t hold the extra volume as the pressure drops: the tissue can tear. This lung overexpansion injury can kill.

What are the signs of a lung injury, and what do you do?

The signs of an arterial gas embolism come suddenly, typically within 15 minutes of surfacing, according to DAN: confusion, weakness or paralysis, loss of consciousness, convulsions, bloody froth from the mouth or nose. Other lung injuries can cause chest pain, breathlessness, a changed voice or a full feeling in the throat.

Treat it as an emergency, as recreational divers are taught: the diver lies down, oxygen if you’re trained, emergency services, then a diving hotline such as DAN’s, and watch their breathing. It’s the same first aid as for decompression sickness.

Which dive training levels cover barotrauma?

Open Water Diver covers pressure, equalizing and the rule never to hold your breath. Rescue Diver covers the first aid for gas embolism, and Divemaster the physics behind it. The Open Water practice questions include equalizing and breath-holding, and the Open Water questions new divers get wrong include pressure, breath-holding and equalizing.

Frequently asked questions

How deep can ear barotrauma happen?

Very shallow. DAN notes that without proper equalizing, ear barotrauma can occur as shallow as 2 to 3 m (7 to 10 ft). Pressure changes fastest, in proportion, in the first meters, so start equalizing before your head goes under and keep going.

Can you scuba dive with a cold?

It’s a bad idea. A cold swells the lining of your Eustachian tubes and sinuses, so air can’t pass and you risk a squeeze. A decongestant may wear off at depth and cause a reverse block on the way up. Wait until you breathe freely, and ask a doctor before taking any medicine for diving.

What is a reverse block?

A reverse block is a squeeze on the way up: air expanding in a middle ear or sinus can’t escape, causing pressure, pain or vertigo while you ascend. DAN Europe links it to decongestants wearing off at depth, poor equalizing and colds. Stop, descend slightly, swallow or move your jaw, then ascend as slowly as you can.

Can you get a lung injury in a swimming pool?

Yes. DAN notes that pulmonary barotrauma can occur in a shallow pool if a diver holds their breath while rising, and warns that even a breath-hold ascent of about 1.5 m (5 ft) in shallow water could be enough. The pressure change is proportionally biggest near the surface. Keep breathing normally, especially in shallow water.

Sources

1. DAN, Ear Equalization Guidelines for Scuba Divers
2. DAN Europe, Ears and Diving
3. DAN, Mask Squeeze (Facial Barotrauma)
4. DAN, Decompression Illness: What Is It and What Is the Treatment?
5. DAN, How to Avoid Rapid Ascents and Arterial Gas Embolism
6. Joseph Gessert, Shallow-Water Arterial Gas Embolisms, DAN Alert Diver (2021)
7. DAN, Recognizing Lung Conditions
8. UHMS, Hyperbaric Oxygen Therapy Indications, Air or Gas Embolism