Why Is It Dangerous to Hold Your Breath While Scuba Diving?

I remember my very first experience with scuba diving, which was a try dive in an indoor pool. The instructor explained how to put on the jacket and breathe from the regulator, equalize our ears and then let us crawl around the swimming pool floor in water shallow enough to stand up in for a couple of minutes. Before the instructor let us vanish under the surface, he said one more thing: Never hold your breath!

You might think that this was not the greatest first dive experience, and in retrospect, I agree, but nevertheless I was instantly hooked! I found breathing under water exhilarating and immediately enrolled in the next Open Water Diver course. Check out the following Scuba Dive Schools worldwide for your next Scuba Dive training:

Where again, I encountered this most important rule when scuba diving, and it was thoroughly drummed into me to never, ever hold your breath!’ This does of course not mean, you have to pump air at an insane rate as some divers seem to think. It just means that you should always keep your airways open so that no air gets trapped in your lungs in case you have to do an emergency ascent.

In this article, we will help to explain the importance of breathing continually while under the water.

You need to understand the physics of diving

To explain and understand the importance of continually breathing underwater we need to look into the physics.

Pressure is everything in scuba diving and as you may know, the deeper you descend, the more the pressure increases. If you think of your lungs for instance, when you take a deep breath above water and then descend five meters, the pressure on your lungs increases and so the volume of your lungs decreases. Even though you haven’t breathed out any of the air, you took in on the surface.

When you breathe air at depth, this air is compressed. And as long as you keep breathing this air can escape. So far so good. If you would breath air at depth and the pressure surrounding you decreases the air will expand. When the air cannot escape in a natural way, it eventually will find a way.

Why is holding your breath while scuba diving so dangerous?

Looking back to the science described above, we can see that as we descend the pressure on our lungs increases and our lung volume decreases. So when we do the opposite and ascend the higher we ascend on one breath of air the more the pressure drops and the more our lungs expand. Overexpansion of the lung can lead to serious injuries.

There are four categories of lung overexpansion injuries

1. Arterial Gas Embolism (AGE):

When a person suffers from AGE, air diffuses into the blood and makes its way up the minuscule capillaries of the brain, forming an air bubble and consequently blocking the blood carrying vessels.

This obstructs the flow of blood in the body and oxygen supply is cut off to vital body tissues. The consequences can be as deadly as paralysis, brain damage, heart stroke, and death. AGE is the most dangerous effect of a lung overexpansion injury and is potentially fatal.
AGE affects the body at a more rapid rate than any of the other manifestation of lung overexpansion injury.

Also read: What is decompression sickness and how can you treat it?

2. Mediastinal Emphysema (ME):

ME is a condition in which air is trapped in the cavities that surround the delicate heart muscles. This air, in turn, places pressure on the heart muscles, which in turn stop functioning properly; as a result, blood supply to the body becomes erratic. This condition is not as severe as AGE, but extreme Mediastinal Emphysema can lead to heart failure.

3. Pneumothorax:

In this condition, the air is collected at the outer side of the lungs causing the lungs to cave in upon themselves. The victim may end up with partial or completely collapsed lungs. Since Pneumothorax involves injury to lungs, it causes acute pain in the chest which may be accompanied by coughing up blood. Pneumothorax worsens as a diver ascends because the pressure on the damaged lung increases with the ascent.

4. Subcutaneous Emphysema:

Probably the least damaging of all common lung overexpansion injuries, Subcutaneous Emphysema is a condition in which air pockets are formed near the collarbone and the neck. With Subcutaneous Emphysema, there is irritation and squishiness in the skin, which may even crack if it is touched.

Do you remember that dive master on your last dive trip?

When the first people start their ascent, he would inflate his SMB (surface marker buoy) by letting a little bit of air in at depth and then releases it. When it reached the surface, the air inside the buoy expanded and completely filled the SMB with air making the buoy stand up in the water so it can be seen by boat drivers and surface support.

If the dive master added to much air into the SMB at depth, it would have ruptured before it made it to the surface. Now imagine that bouy being your lungs. Therefore the simple rule “Never hold your breath while scuba diving

Also read: Learn how to lower your air consumption with this simple trick.

Better safe then sorry

If you want to get all technical about it, it is possible to hold your breath while scuba diving as long as you neither ascend or descend.

The reason why you are taught to never, ever hold your breath is because it is an easy bad habit to fall into and one that when done unknowingly can lead to severe illness or even death.

Even if you lose your regulator underwater or run out of air, you should breathe out as you ascend to the surface (don’t worry, this is easier than it sounds, since you are only releasing the excess air from your lungs as it expands!)

After all that is said and done, remember that there are other contributing factors that will make you more susceptible to a lung overexpansion injury.

You should avoid diving with a cold, chest infection (even minor) or any form of congestion (do not dive with a cough!). If you are a smoker, quit, or at least do not smoke two hours before the dive and in the case of a history of lung injury, get checked by a physician.

And always remember that diving is not a high-risk sport, and accidents are very rare. You probably are at higher risk of slipping by the pool or on the boat and hitting your head or breaking a leg! And then there are always the falling coconuts to watch out for!

Blog written by Rutger who is an avid scuba diver and loves to travel, dive and write about scuba diving. Based in Amsterdam, he at least twice a year plans a dive trip of the beaten track.

This article is published by The Scuba Page, the online magazine for Scuba Dive lovers around the world. The Scuba Page is part of RUSHKULT: the online booking platform for adventure sports. Visit the RUSHKULT platform to book your next Scuba Dive training, guided trip and accommodation.

[the_ad_group id="1252"]