By Mario Medarevic
Published on DiveWorld.ca
Diving is an escape, a passion, and often a deeply calming experience. But sometimes, even experienced divers encounter unexpected medical issues that seem to appear from nowhere.
One of the lesser-known — but potentially serious — conditions is Immersion Pulmonary Edema (IPE). It occurs when fluid leaks from the blood vessels into the alveoli (air sacs) of the lungs during immersion. This isn’t due to swallowing water — it’s your own body fluid flooding your lungs.
The result?
Sudden shortness of breath, coughing, and in some cases, blood-tinged sputum — symptoms that often appear mid-dive or immediately after surfacing.
Unlike drowning, the fluid in IPE comes from inside the body. And unlike decompression sickness (DCS), it doesn’t involve gas bubbles or require recompression therapy.
Treatment typically involves:
100% oxygen
Medical evaluation
Diuretics in more severe cases
Most cases resolve quickly, but recurrence is possible. That’s why it’s essential to stop diving immediately, get assessed, and only return to diving under medical guidance.
IPE is still not fully understood, but researchers and dive physicians have identified several contributing factors:
Cold water immersion (but it’s also been seen in warm water)
Tight or poorly tuned regulators that cause breathing resistance
Strenuous surface swimming
Pre-existing conditions like high blood pressure or undiagnosed heart disease
Hydrostatic pressure redistributing blood toward the chest
Overhydration before a dive
Interestingly, IPE has also occurred in healthy athletes — including Navy divers and triathletes — with no medical issues and no obvious triggers.
One of the key insights from IPE research? Breathing resistance matters — a lot. Divers using tight or poorly maintained rental regulators have reported difficulty breathing, which may contribute to fluid leaking into the lungs.
That’s why owning a well-tuned, high-quality regulator is not just a luxury — it’s a smart safety investment.
Similarly, cold shock is another major factor. Enter the drysuit.
A proper-fitting drysuit doesn’t just keep you warm — it minimizes physiological stress that might otherwise trigger IPE, especially in deeper or longer dives where core temperature matters.
In many cases, yes — but only with the proper medical evaluation. Divers should:
Be cleared by a dive-savvy physician
Avoid overexertion and overhydration
Use a well-maintained, low-resistance regulator
Dress appropriately for conditions — dry exposure protection is preferred
Monitor and manage blood pressure and cardiac health
If the episode was isolated and all symptoms have resolved, a return to diving may be possible. However, divers who experience multiple episodes of IPE may need to reconsider diving altogether.
Despite decades of study, the diving and medical communities still don’t fully understand the root cause of IPE or who is most at risk. Current research, including a collaborative study between Dr. Richard Moon of Duke University and DAN, aims to identify patterns and genetic predispositions.
Until we know more, the best advice is simple:
✅ Dive smart
✅ Stay warm
✅ Use reliable, tuned gear
✅ Know your limits
At Dive World, we believe education and proper gear go hand in hand. That’s why we strongly encourage divers to:
🔹 Invest in a personal regulator — one you trust, know, and service regularly
🔹 Upgrade to a drysuit — especially for Canadian and cold-water dives
🔹 Stay informed — keep up with DAN alerts and medical findings
Not sure where to start?
Our team is happy to help you choose the right equipment tailored to your diving goals and physiology.
➡️ Shop regulators | Explore drysuits | Book a gear consult
Visit DiveWorld.ca or drop by the shop — because your safety is worth the investment.
Questions? Call us at 416-503-3483 and speak to an experienced professional.