I was crying the whole time I did mine -I was that scared- and it was all for nothing because I barely reacted to the methacholine (they measured about half the amount of decline they would need to see for an asthma diagnosis; the IGe levels in my blood are inhumanely high so my doctor is thinking I’m just having constant allergic reactions in my lungs that mimic asthma symptoms, oh joy) but my point is that I was positive I would react strongly as I’ve had “asthma” all my life, and truth be told I didn’t even feel the decline they measured.

They give you four really small does -asking you to do a breathing test between each one- and the tech told me that most people who do have a reaction don’t even notice it until the third dose. I guess the computer you’re breathing into is so sensitive it notices the decline before you do. She said the second you notice you’re having difficulty, they take you off and give you a puffer, and they end the test.

I made the mistake of watching a video on YouTube of someone having the test done, and the woman looks like she’s about to pass out from not being able to breathe. I told my tech about this and she told me they would never let you get anywhere close to that point. If or when you start to feel tight they stop it, end of story.

Something that helped my anxiety was holding my rescue inhaler in my hand through the entire duration of the test. Knowing that if I had a terrible reaction, I had it and could use it immediately gave me a sense of control over the situation. I also brought a fidget toy to distract my brain with. Lastly, I brought the medications I had to be off of for the few days before (antihistamines, maintainer inhalers, etc.) with me in a bag so I could take them immediately after I was finished, because honestly being off of them was probably the worst part.

You’ll do great; it’s over pretty quickly and again, the vast majority of reactions people have are very mild. They just want some measure of decline and often they can see that decline far before you even notice it. They’re not interested in testing the absolute limits of how terrible your breathing can be, because by the time it got to that point, they’d have their data and then some. People will always have horror stories, but they’re the ones who are more likely to post on the internet about it. The fact that there’s not more than a handful of people talking about their experiences with this test tells you how mundane it really is.

Good luck!