Here is the problem I have. Back in 2001 I went to the doctor for what I thought was some type of asthma. I did IMLP that year and was having a hard time breathing during the run. My breathing was really shallow and if I tried to force a deep one I started gasping. The doctor did some test and gave me an inhaler. I don't remember exactly, but it was something you are only suppose to take every 90 minutes or so max. It never really did much and I did IM Moo in 2002 with the same problem. I used the inhaler so much that it lowered my blood pressure a lot. I stopped using it after that. The breathing issue only happens in long tri's and long rides (4+ hours). Maybe it would happen just from running if I ever ran that long.

So my question is does any one an idea what could cause this? I thought about bike position, but it has happened on 4 different bikes, with different positions, and different types of courses (flat/mostly aero and hilly/some aero, some climbing). I got FISTed a year ago with no relief of the issue. I have noticed it seems to get better if I drink a lot once I notice it starting so maybe hydration, or maybe that masks the problem. It happened at IMAZ this past weekend and was a little bit of a buzz kill on the marathon.

Thanks for the help.