I met a kinesiologist a few years ago who had been working for 30 years with clients. He told me asthma is sorrow and was pretty sure about that. He had never met a client with a different pattern. We worked on my issues for one hour, and my asthma was then GONE for more than a year... until next issue of sorrow bubbled up, and I locked it in instead of letting it flow through the body with awareness.
I have not found AYP spinal breathing to be enough to release the asthma symptoms. That brings progress in the long run of course, but for faster results I guess more intense pranayama with intention on asthma would be necessary to release the blockages of sorrow.