While I'm not certified yet, I have gone through the process of trying to get medical approval twice. I grew up with bad asthma but the past decade+ it's been very well controlled and pretty much I have grown out of it. I still use Advair like 4-5 times a week (its recommended 2x a day) and I haven't used my rescue inhaler in over a decade.
Back in 2011, the first time I went to a doctor that DAN recommended that was way out of the way for me. He was about 45 minutes away. I went to him about 2 weeks before I was going to Mexico where I was planning on doing SCUBA.
Before I visited him he had me do a bunch of tests and to basically bring the results in. The tests included chest x-ray, pulmonary function tests, blood tests, and like 2 other tests I don't even remember. He didn't have me do the physical part of it because he saw the kind of shape I was in and said it would be pointless since he knows I'd pass it. In the end he said that he would not sign off the waiver just because he doesn't do it. He flat out told me that I can answer NO to all the questions because I clinically didn't even have asthma, like by the definition of it.
I left disappointed, and the next day he called me and said that if I did SCUBA in Mexico and everything felt fine, to come visit him again and he'd sign off. Well I went and I did a 1 tank resort dive and loved it, however I was dumb at the time and never went back to see him.
Fast forward 7 years later to this past August, I decided that I was going to actually do it this time and went to see my asthma/allergy doc. I explained the situation to her and she said she doesn't really have education on it and recommended me to see a pulmonary specialist. So I went and saw him, he had me do some breathing tests, I did this "6 minute challenge" where they test me before/after walking fast for 6 minutes and I passed that just fine. He then said that he wanted me to go to a hospital and do tests they can't do there, as well as get a chest x-ray.
So I did the x-ray, went to the hospital and did a pulmonary function test 3 days. They then took my oxygen levels in my blood, put me on pure oxygen for 30 minutes, and took my blood again. After I was done with all of the tests, the guy giving me the test asked me why I was doing these tests and I told him because I want to get SCUBA certified. He thought that it was odd because he hadn't heard of it being needed and then I told him I had asthma. He looked at me with almost a double take and was dumbfounded, and was like "you have asthma?" I told him yes and he was shocked and said he never would have guessed.
A week or so later, the results made it to the pulmonary specialist and he signed off on my waiver. So I'm now waiting for my classes to start next weekend then heading to Grand Cayman for the checkout dives.
I feel better knowing that I can answer YES to the asthma question on there as well as taking medication, and then give them my waiver. I will also gladly explain to anyone that I have very mild asthma and it's controlled very well and it should not be an issue at all. I workout and exercise regularly too which I'm sure helps.
I write all this out because in the end I was glad I went through all of this. Sure it took more time, but it also educated me about the risks associated with asthma and diving, and due to my asthma and how it is very mild/controlled, I'm at very minimal risk, pretty much no more risk than anyone without asthma. I did get a bit frustrated at having to go somewhere, then go somewhere else, then somewhere else, etc, and in the end I wasn't sure if I'd get it signed off, but it all worked out.
You all may have seen my story on this forum here about all of this as well, as I made a post back in 2011 and updated it recently.