How Does Scuba Diving Work?

Scuba diving works using gear that allows you to breathe underwater and a specialized set of skills. Scuba stands for “self-contained underwater breathing apparatus”, and the activity is separate from other forms of diving that do not use breathing devices.

In this article, we focus on how you breathe and move up and down while scuba diving. We also answer a few questions regarding your health while scuba diving.

Contents hide

1 Do You Breathe Through Your Mouth or Nose When Scuba Diving?

1.1 Breathing Through Your Nose While Scuba Diving

2 How Do Scuba Divers Go Up and Down?

2.1 Buoyancy and Diving

2.2 Tools to Move Up and Down

3 What Happens If You Cough While Scuba Diving?

4 Why Do Your Ears Hurt When Going Underwater?

4.1 Risks of Ear Pain While Diving

5 What Happens If You Ascend Too Quickly in Water?

5.1 Common Reasons for Rapid Ascent

5.2 What to Do Following a Rapid Ascent

6 What Happens If You Get the Bends?

6.1 Symptoms of Decompression Sickness

7 References

Do You Breathe Through Your Mouth or Nose When Scuba Diving?

You breathe through your mouth when scuba diving.

You use a collection of gear designed to allow you to breathe underwater, but this only works when breathing through your mouth. The system includes your air tanks and a two-stage regulator.

The regulator’s first stage connects directly to the tank’s valve outlet, and it reduces the high pressure in the tank to an intermediate pressure. This first stage has several hoses that run from it, but the one that connects to the second stage is what you need for breathing.

The second stage of a regulator is the part that you breathe through. This stage feeds you air through a demand valve that only opens up and delivers the air when you need it.

When you breathe out, the first valve closes and another opens to let the air out. Not only does this prevent water from coming in as you exhale, but it prevents the air from leaking while you breathe.

Breathing Through Your Nose While Scuba Diving

Unless you are wearing a full face mask while scuba diving, there is no way to get the air you need by breathing through your nose while scuba diving.

Instead, your mask encloses your nose and makes a seal. You still have a flexible pocket around your nose to pinch it while equalizing your ears, but the seal plays a different role.

Without keeping your nose in the mask, you would not have an easy way to clear your mask if it fills with water. When this happens, you breathe out through your nose to push the water out.

Exhaling through your nose also helps with mask squeeze. When descending, the air compresses and causes the mask to push onto your face. By exhaling, you add more air to the area and prevent pain and potential eye damage.

How Do Scuba Divers Go Up and Down?

Scuba divers move up and down in the water using tools that affect their overall buoyancy.

These include:

Dive weights
A buoyancy control device
Certain breathing techniques

Before you understand how these tools work, you should understand the basics of buoyancy while diving.

Buoyancy and Diving

Buoyancy refers to the upward force that acts opposite of a diver’s weight while they are in the water. You can have:

Positive buoyancy, meaning you’re inclined to float to the surface
Negative buoyancy, meaning you’re inclined to sink deeper
Neutral buoyancy, meaning you will hold your position

Humans have a naturally positive buoyancy because of the air that they hold in their lungs and their body fat. You also wear positively buoyant items, such as your diving suit, so you need to find ways to achieve negative buoyancy if you want to go down in the water.

Tools to Move Up and Down

Moving up and down in the water involves the use of specific tools and techniques.

You use a dive belt or other weight holding apparatus to add more negatively buoyant weight for the purpose of descent. This may seem counterproductive, but using the proper weight alongside a buoyancy control device allows you to descend at the rate you need, then maintain a neutral position.

With more training, you can use special breathing techniques to decrease your buoyancy and reduce the need for as much weight.

What Happens If You Cough While Scuba Diving?

A single cough while scuba diving doesn’t do much. The air leaves your lungs and exits the regulator, but because it only goes in one direction, you don’t need to worry about swallowing water.

A greater concern is the possibility of losing the regulator, but this isn’t high.

If you have persistent coughing underwater, you can exhale more than you need and lead to an increase in air consumption. This is part of the reason it is not recommended to dive while you are sick.

Why Do Your Ears Hurt When Going Underwater?

The further you dive, the more pressure you put your air cavities under. Your lungs are constantly equalizing due to the tank you’re connected to, but your ears will hurt until you relieve the increased pressure on your eardrums.

Normally, the pressure is the same inside and outside of the ear. When you’re underwater, the greater pressure on the outside pushes against your inner ear.

Counterbalancing can only occur when air pressure reaches the inner surface of your eardrum through the Eustachian tube which links the ears to the nose and throat. Equalizing methods allow you to open up this tube.

Risks of Ear Pain While Diving

Ideally, you don’t reach a point of pain. It’s far too easy for the pressure to sneak up on you.

At the low end of risks, your ears are in pain and uncomfortable until you correct the issue.

You’re at risk for your eardrums swelling and bulging. They can burst, and then seawater will rush into your middle ear and cause nausea, dizziness, and vomiting, along with a plethora of symptoms that accompany a ruptured eardrum.

What Happens If You Ascend Too Quickly in Water?

Ascending too quickly increases your risk of issues such as DCS and pressure-related injuries such as:

Pulmonary barotrauma
Pulmonary embolism
Pneumothorax

Most people don’t ascend rapidly for fun, and there are ways to prevent it from happening as well as procedures to follow immediately after.

Common Reasons for Rapid Ascent

The most common reasons for rapid ascension include:

Human error, such as mismanaging air or failing to measure your ascent rate
Loss of weight or inadequate buoyancy control
Failure of your equipment (i.e. BCD)

In most cases, preparing through training and checking your equipment is the best way to avoid this situation. The more prepared you are, the more steady you can stay during an emergency.

What to Do Following a Rapid Ascent

Your dive computer may warn you of rapid ascent, but if you bypass your safety stop and reach the surface, you need to start establishing positive buoyancy and signal someone over. They will help evaluate your dive profile and condition.

If you don’t have symptoms after a minute or two and feel comfortable, you can drop back down to do a safety stop. Any symptoms require immediate medical attention.

What Happens If You Get the Bends?

There are many paths to go down after you get the bends.

In some cases, you feel a little sick and get better with little to no intervention. Some cases require more attention, anywhere from a few hours of observation to in-patient treatment.

In the worst situations, decompression sickness can be fatal.

Symptoms of Decompression Sickness

Most symptoms of DCS involve the nervous and musculoskeletal systems and develop within 6 hours of surfacing. You can develop symptoms up to 48 hours later.

These are split into Type II mild symptoms and Type II severe symptoms, and show up in ways such as: