Can You Scuba Dive With Asthma?

Yes, in many cases. If your asthma is mild and well-controlled, current medical guidance from the Undersea and Hyperbaric Medical Society (UHMS) and Divers Alert Network (DAN) says diving can be an acceptable risk, provided you meet specific conditions. Severe or poorly-controlled asthma is a different matter, and the guidance there is clearer: don't dive until it's under control.

That's the short answer. Here's the longer one, because "it depends" isn't useful without knowing what it depends on.

Why Asthma and Diving Interact the Way They Do

Underwater, breathing capacity drops for every diver, asthmatic or not. At around 10 metres, a diver's maximum breathing capacity falls to roughly 70% of what it is on the surface. At 30 metres, that figure drops closer to 50%. For a diver whose airways are already narrowed by asthma, there's less reserve to draw on when the body needs more air, whether from exertion, cold water, or stress.

The specific danger isn't just breathlessness. If airways narrow or fill with mucus during ascent, air can get trapped in the lungs while surrounding pressure drops. That combination is what causes pulmonary barotrauma, and in serious cases, arterial gas embolism: air forced into the bloodstream through ruptured lung tissue. It's a rare event, but it's the reason diving medicine has historically treated asthma with caution.

What "Well-Controlled" Actually Means for a Diver

DAN's current position, following the 1995 UHMS consensus guidelines, is that divers with mild intermittent, mild persistent, or moderate persistent asthma may be cleared to dive if their condition is genuinely well-managed. In practice, that tends to mean:

• No use of a reliever inhaler in the 48 hours before diving
• No symptoms triggered by cold air, exercise, or emotional stress (exercise-induced and cold-induced asthma are treated more strictly, since both are common triggers underwater)
• Normal lung function on spirometry testing
• No chest symptoms present on the day of the dive

Severe or brittle asthma, meaning daily or chronic symptoms even with treatment, falls outside these guidelines. The general medical position there is straightforward: diving isn't recommended until control improves.

This Isn't a Self-Assessment

None of the above is something to self-diagnose against a checklist. PADI's standard medical questionnaire flags asthma as a condition requiring sign-off from a doctor, ideally one familiar with dive medicine, before certification. DAN offers this kind of assessment directly, and it's worth doing properly rather than assuming mild childhood asthma still applies in the same way it did twenty years ago.

At Scuba Evolution, every student completes a standard medical screening questionnaire before training begins. If asthma or any respiratory condition is flagged, we'll ask for medical clearance before you get in the water. That's not bureaucracy for its own sake. It's the same reasoning DAN and UHMS built their guidelines on: control the variable you can control before you're 18 metres down.

Frequently Asked Questions

Can I dive if I only get asthma symptoms occasionally?
Mild intermittent asthma, well-controlled and symptom-free, is generally viewed as compatible with diving under current guidelines. A doctor's assessment, ideally including spirometry, is the way to confirm this rather than assume it.

What if my asthma is triggered by exercise or cold?
Exercise-induced and cold-induced asthma are treated more cautiously, since both triggers are common underwater. Some guidelines exclude divers with these specific triggers from diving altogether.

Do I need a doctor's clearance to dive with asthma?
Yes. PADI's medical questionnaire requires sign-off from a physician if asthma is disclosed. This isn't optional, and a good dive operator won't let you skip it.

Can using an inhaler before a dive make it safe?
Needing a reliever inhaler within 48 hours of diving is generally treated as a reason to postpone the dive, not a workaround. The concern is airway stability during the dive itself, not just symptom suppression beforehand.

Is this different for children or junior divers?
Junior certification carries the same medical screening requirements. Age doesn't change the underlying physiology; a doctor's assessment is still the standard for asthma at any age.

This article is general information, not a medical opinion on any individual's fitness to dive. If asthma or any respiratory condition applies to you, speak to a doctor familiar with dive medicine, or contact DAN Southern Africa directly, before booking a course.