Are you suggesting asthma is a minor medical condition for diving?
I don't see any questions on the medical form about blindness or severely diminished eyesight. So does that therefore suggest that blindness is not relevant to diving?
As Russoft mentioned asthma exists on a spectrum. That means for some people (like myself) it may as well not even be an issue. My asthma is well-managed clinically and unless you expect me to dive for more than 24 hours straight then as an instructor if a doctor tells you "this guy can run a Marathon without an asthma problem" then what the heck do you have to get worked into a knot over?
That doesn't mean everyone with asthma gets a free pass to go diving - it means that anyone who wants to become a diver should speak with their physician and share literature about diving and get tests to ensure that diving is NOT contraindicated. And that's exactly what I did. But because my doctor refuses to sign a form that brings him into the legal process and makes HIM personal liable, you wish to exclude divers from training? Sorry, but my instructors were FAR more concerned with my personal health and my personal understanding of the risks and be assured that I did see a doc and get checked out before getting into this, and I provided a letter to that extent and they logically and rationally realized that was what was most important. The form is a formality, not a stopgap.
---------- Post added September 9th, 2015 at 05:23 PM ----------
BTW - don't just take my word for it, the UHMS and DAN have both done plenty of research on the topic of asthma:
Asthma & Diving
Can I Dive With Asthma, Diabetes, Cancer, or Heart Disease, and after suffering DCS and Pneumothorax? | Scuba Diving
Medscape: Medscape Access
Alert Diver | Tobacco, Marijuana and Asthma
Diving Medicine
If you think that having asthma IN ANY WAY AT ALL precludes you from being able and capable of diving (regardless of your placement on the asthma spectrum), then your line of thinking is outmoded by research and decisions made by these institutions nearly 20 years ago. Also in 1995 there were no long-term daily anti-asthma medications such as Advair and Qvar, which literally eliminate any possibility for asthma attacks if taken on a daily basis. Those treatments have also been cleared by the UHMS as having no specific interactions or complications with diving (according to my dive doc, otherwise I would link you to a citation for that).
BTW tursiops, you're in Australia right? Australia has the most restrictive standards for asthmatics before they can be cleared to dive: spirometry tests before and after strenuous exercise must be above 90% FEV1/FVC. Even by Australian standards I'm all set - my FEV1 was 103% and my FVC was 105% (for an FEV1/FVC of 98%) when tested by my dive doc. Knowledge about the requirements is no replacement for the decision of a medical doctor to put their neck on the line for you by signing a liability waiver that puts them square in the crosshairs for a lawsuit if you get tangled in kelp and die, for sure, but it might just make you a more educated and reasonable person and feel more personally comfortable with the 7% students who would like to dive and have a simple and potentially manageable disease.