COPD: Incompatible With Diving

I was diagnosed with chronic obstructive pulmonary disease (COPD) last summer. I get short of breath when I exercise, but I still swim for about an hour three times a week, including a 75-foot underwater swim with fins. How will COPD affect my diving?

Unfortunately, COPD is a contraindication to diving for several reasons. With COPD, there are abnormal enlargements of the air spaces in the lungs and destruction of the air sac (alveoli) walls, reducing their elasticity. The alveolar walls are normally elastic like a balloon. A balloon expands when you breathe into it, but the walls are ready to recoil and expel the air, which is how normal alveoli function. With reduced elasticity, it is more like breathing into a plastic bag. It expands, but the walls do not actively force out the air. Any air remaining in the alveoli creates a much higher potential for pulmonary barotrauma.

The volume of gas is inversely proportional to its absolute pressure, which your open-water instructor probably demonstrated to you using a balloon. The balloon filled with air at depth expands during ascension, which teaches the importance of never holding your breath while diving. If your lungs cannot quickly expel all the air, it creates a situation similar to partially holding your breath while diving since the trapped air will expand, possibly to the point of rupturing your lungs. A rupture leads to air escaping the lungs and potentially entering arterial circulation, which can cause an arterial gas embolism (AGE), or the chest, resulting in a life-threatening pneumothorax. The bubbles that cause an AGE may lodge in the lungs, heart or brain and result in a pulmonary embolism, heart attack or stroke, respectively.

Some people with COPD retain carbon dioxide (CO2), which creates a risk of CO2 toxicity at depth. Reduced exercise tolerance is also common for those with COPD and poses risks for diving. There can be strenuous activity involved with managing currents, swimming on the surface in choppy seas or pulling yourself and your wet, heavy gear up a ladder and onto an unsteady boat. You may also have to walk in full gear along a boat deck after an exhausting dive.

With COPD, shortness of breath during exertion doesn’t mean you are out of shape; it means you cannot rid your body of CO2 and replace it with the oxygen needed to meet the demand of your exertion. Should you continue to push yourself, your heart may race, and you can experience an elevated breathing rate, panic or even hypoxia (insufficient oxygen) and pass out.
— Brandi Nicholson, MS, EMP-T