What Happens If You Cough While Scuba Diving? A Deep Dive into Potential Problems and Solutions

Scuba diving is an incredible experience, allowing us to explore a world beneath the waves that most people only dream of. However, it also comes with its own set of unique challenges and potential risks. One common question that pops up, especially for new divers, is: "What happens if I cough while scuba diving?" It seems like a simple reflex, but in the underwater environment, it can have significant consequences.

Let's break down why coughing underwater is a concern and what can happen if it occurs.

The Mechanics of Coughing Underwater

Normally, when you cough, your glottis (the opening between your vocal cords) closes momentarily to build up pressure in your lungs, and then it snaps open, expelling air and any irritants. This is a powerful expulsion of air.

Underwater, the situation is drastically different. Your scuba regulator delivers a continuous supply of air at ambient pressure. This means that if you inhale forcefully, you're getting a full lungful of air. If you then try to cough, you're attempting to expel a large volume of air rapidly, and this is where the problems begin.

Potential Risks of Coughing While Scuba Diving

The primary concern with coughing underwater is the potential for lung overexpansion, also known as lung barotrauma. Here's how it can happen:

Air trapping: When you cough underwater, especially if you try to hold your breath or cannot exhale effectively, the air in your lungs can become trapped. Your regulator is still supplying air, and the pressure outside your body is equalizing with the pressure inside your lungs.
Ascent and pressure changes: If you are in the process of ascending or if the air is trapped and you remain at depth, the pressure within your lungs is increasing. As you ascend, the ambient pressure decreases. Normally, this allows the air in your lungs to expand safely. However, with trapped air from a cough, the expanding air has nowhere to go.
Lung tissue damage: The trapped air, unable to escape, will expand beyond the capacity of your lung tissues. This can cause the delicate air sacs (alveoli) in your lungs to rupture.

Specific Consequences of Lung Overexpansion

The rupture of lung tissue due to overexpansion can lead to several serious conditions:

Pneumothorax (Collapsed Lung): Air can escape from the ruptured alveoli into the space between your lung and your chest wall. This can cause your lung to collapse, making it difficult to breathe.
Mediastinal Emphysema: Air can escape into the mediastinum, the space in the chest cavity that contains the heart, esophagus, and trachea. This can cause chest pain and shortness of breath.
Subcutaneous Emphysema: Air can escape from the mediastinum and travel into the tissues under the skin, often causing a crackling sensation when you touch the affected area.
Arterial Gas Embolism (AGE): This is the most dangerous consequence. Air can enter the bloodstream from the ruptured lung tissue and travel to the brain or other vital organs. This can cause stroke-like symptoms, paralysis, unconsciousness, and can be fatal if not treated immediately.

It's crucial to understand that these are serious medical emergencies. The golden rule of scuba diving, "Never hold your breath," is directly related to preventing these issues, and coughing can inadvertently lead to breath-holding.

What to Do If You Feel the Urge to Cough

The best approach to coughing while scuba diving is prevention and immediate action if it happens.

Stay calm: Panicking will only make the situation worse. Take slow, controlled breaths.
Exhale, exhale, exhale: The absolute priority is to exhale as much air as possible. If you feel a cough coming on, consciously try to blow bubbles. This will help release air from your lungs.
Ascend slowly and under control: If the cough is persistent or you are struggling to exhale, you must ascend slowly and continuously exhale. Do not ascend without exhaling.
Signal your buddy: Immediately signal to your dive buddy that you are having a problem. They can assist you and provide support.
Seek medical attention: Even if you feel fine after a coughing episode and a controlled ascent, it's always wise to get checked by a medical professional, especially a doctor familiar with diving medicine.

Preventing Coughing While Diving

Several factors can contribute to coughing underwater, and by addressing them, you can minimize the risk:

Water Ingress into the Regulator: This is a common cause. Ensure your regulator is properly sealed and that you are not clearing your mask or BCD in a way that splashes water into the mouthpiece. If water enters, don't panic; clear it by exhaling forcefully.
Illness or Allergies: Diving with a cold, congestion, or active allergies significantly increases your risk of lung overexpansion. Your airways might be narrowed, making it difficult to equalize pressure and exhale properly. It's best to postpone diving until you are feeling completely well.
Cold Water: Cold water can sometimes trigger a gag reflex or cause you to involuntarily inhale water. Wearing appropriate exposure protection can help.
Anxiety or Excitement: Sometimes, the sheer excitement or a bit of anxiety underwater can lead to rapid breathing, which can sometimes trigger a cough. Practicing relaxation techniques and familiarizing yourself with your equipment can help.
Overexertion: If you are struggling with buoyancy or swimming against a strong current, you might become fatigued and start breathing erratically, potentially leading to a cough.

Your scuba training emphasizes slow, controlled breathing and the importance of exhaling throughout your ascent. These principles are not just guidelines; they are critical safety measures. Understanding what can happen if you cough while scuba diving reinforces the importance of adhering to these fundamental diving practices.

Frequently Asked Questions (FAQ)

How can I prevent water from entering my regulator and causing me to cough?

Water can enter your regulator if it's not properly sealed, or if you accidentally splash water into the mouthpiece while clearing your mask or adjusting your gear. To prevent this, ensure your regulator is securely in your mouth and practice a controlled exhalation when clearing your mask. If water does get in, don't panic; exhale forcefully through the regulator to clear it.

Why is it so dangerous to hold my breath while coughing underwater?

Holding your breath while coughing underwater traps air in your lungs that is at ambient pressure. As you ascend, the surrounding water pressure decreases. If this trapped air cannot escape, it will expand rapidly, potentially rupturing the delicate tissues of your lungs. This can lead to serious conditions like pneumothorax or arterial gas embolism.

What should I do if I start coughing uncontrollably underwater?

If you feel an uncontrollable urge to cough, your immediate priority is to exhale as much air as possible. Consciously try to blow bubbles. If the cough is severe or you cannot exhale effectively, you must ascend slowly and continuously exhale. Signal your dive buddy immediately for assistance.

Why is it recommended to see a doctor after coughing underwater, even if I feel okay?

Even if you manage to ascend slowly and exhale, there's a possibility of minor lung tissue damage or air bubbles entering your system that might not immediately present with obvious symptoms. A medical professional, particularly one familiar with diving medicine, can assess you properly and rule out any latent issues, ensuring your long-term health and safety.