Reverse Block in Scuba Diving

Anyone who has spent any time in the water has probably experienced the pain that can occur if your ears are not equalized properly. It can happen in as little as two to three meters of water, so many people first experience it in a swimming pool. 

Air is trapped in the normally-closed eustachian tubes of the middle ears. During a dive the pressure of the water increases the deeper we go and this causes pain in our ears unless we equalize it to counteract the water pressure. 

There are many ways to physically equalize the ears. The most common method taught to divers is to hold your nose to prevent the escape of air and then exhale. You should notice an immediate release of the pressure and a little pop or squeaking sound as your ears equalize. If you continue to descend, you’ll have to do it again and again until you reach your target depth. 

Dive courses will teach different equalization techniques, and you should learn different equalization techniques until you find the one that works best for you. Some people find that swallowing or moving their jaw while pinching their nose works better than exhaling. Some people find that thrusting their jaw forward helps them equalize. Know several of these techniques in case your favorite isn’t working for you on a dive. 

But what happens during a reverse block in scuba diving? The reverse block happens when you’re ascending, which may surprise you if you’ve never encountered it before. Your first thought may be to equalize your ears normally, but don’t! The air in your ears is causing pain because it’s being blocked from escaping as it expands. By equalizing, you’ll just be increasing the pressure in your ears and could risk ear barotrauma, or a rupture in your ears. 

Instead, stay at your depth, and relax. Give your ears some time to equalize on their own. It can take 10-15 minutes, which is one of the reasons why you should always plan your dive leaving a safety measure of extra air in your tanks. Equalizing your ears only increases the pressure, and the pain is caused by air in your ears expanding as you ascend.

Descend back down a few meters until you feel the pressure ease. Then try ascending again at a slower rate. You should also notify your dive buddy that you’re having trouble ascending. 

One of the first things you learn when you begin diving is never to dive when you have a cold or any sinus congestion. Most reverse blocks in diving are caused by mucus in the ear canal blocking the natural air expansion as we ascend. Many divers use decongestants and other sinus relief aids to help ensure their sinuses are clear when diving and these medications may not work as effectively when you’re halfway through a dive.  

The best prevention for reverse block is to avoid diving when you have a cold, allergies, or a sinus headache.

There are generally divided opinions on wearing earplugs for diving. Many diving associations and regulatory bodies recommend avoiding them completely, while other divers swear by them, claiming that they make equalization easier. Earplugs may be an answer to diving with an exterior ear infection, but they should never be relied on to dive with any type of sinus congestion.

If you choose to try them, you should buy vented earplugs, which have a small hole that allows for equalization without allowing water into the ear canal. However, you should ensure that you can also equalize your ears effectively without relying on earplugs, just in case. The plugs should never be seen as a diving shortcut that allows you to dive with a cold or sinus congestion. 

Giant Stride offers a wealth of information on reputable diving courses in Thailand. We have both beginner and advanced certified diving courses, plus day diving trips and multi-day liveaboard diving adventures. You can quickly and easily book a dive trip or course directly through us. Explore our website and learn everything you need to know about diving in Thailand!