Diving with asthma or diabetes: the modern fitness-to-dive view (see a dive doctor)
Once an automatic 'no', asthma and diabetes are now assessed case by case. Here's calm, general (non-medical) education on the modern view — and why only a dive physician can clear you.
Not long ago, ticking 'asthma' or 'diabetes' on a dive medical form was treated as an automatic disqualification. The modern view is more nuanced: many people with well-controlled asthma or diabetes can be assessed individually and, in suitable cases, cleared to dive. The crucial word is 'assessed' — by a doctor trained in dive medicine, never by a form, a dive shop, or an article like this one. This is general education to help you understand the landscape before you have that essential conversation.
Why these conditions matter underwater
Both conditions interact with the unusual demands of diving. With asthma, the concern centres on airways that can narrow, and on how breathing compressed gas under exertion and changing pressure might affect them. With diabetes, the concern is around blood-sugar control underwater, where the early signs of a low can be hard to spot and harder to treat than on land. Neither is a simple yes or no — which is exactly why individual assessment replaced the old blanket bans.
What a dive doctor weighs up
- How well controlled the condition is, and how stable it has been over time.
- Your triggers, medication, and how your body responds to exertion.
- For diabetes, your blood-sugar management and awareness of warning signs.
- For asthma, your lung function and history of recent or exercise-induced symptoms.
The modern fitness-to-dive assessment
Today's approach is risk assessment, not a checkbox ban. A physician trained in diving medicine reviews your specific situation, sometimes with lung-function tests or other checks, and may clear you to dive, clear you with conditions, or advise against it. People who are cleared often dive for years safely — but that clearance is personal to them and their current control of the condition, and it can change. This is why the assessment isn't a one-off box to tick and forget.
General education, not medical advice — see a dive doctor
Nothing here can tell you whether you personally can dive. Asthma and diabetes are exactly the conditions where you must get a proper fitness-to-dive assessment from a physician trained in diving medicine. Treat their decision as the authority; this article only helps you arrive prepared.
The cost — and why it's worth it
A specialist dive medical costs more than a routine sign-off, and may add lung-function or other tests. Set against the alternative — diving without proper clearance on a condition that genuinely interacts with pressure — it's money well spent. Think of it as a core part of the cost of diving safely with a managed condition, not an optional hurdle.
| Standard medical questionnaireFlags conditions that need a doctor's review | Low cost or included |
| GP / referral letterMay be needed before a specialist visit | Low to moderate |
| Dive physician assessmentThe essential step for asthma or diabetes | Moderate |
| Additional testsE.g. lung-function tests, where advised | Variable |
| Best value | A proper dive-medicine assessment, done once and renewed as advised |
Budget the medical into your trip
If you have asthma or diabetes, build the cost and the lead time of a dive-medicine assessment into your plans early — before you book a non-refundable course. It's a small, high-value line item that protects everything else you spend.
Cleared is personal and current
A friend with the same condition being cleared tells you nothing about your own clearance. Fitness to dive is assessed individually and reflects your current control of the condition — so get your own assessment, and update it as advised.
For the wider picture on health screening before you dive, see our guide on medical fitness to dive.
Bottom line: asthma and diabetes are no longer automatic disqualifications — modern practice assesses them individually, and many people with well-controlled conditions are cleared to dive. But that clearance can only come from a physician trained in diving medicine, never from a form or an article. Budget the assessment in early, treat it as essential, and let the dive doctor's decision be the one that counts.