If you can't cycle well, your asthma is not under optimal control. See you doctor. In most patients, asthmsa is relatively easy to control if they are compliant with the proper treatment regimen. Many patients need combination treatment. Often the treatment includes the use of a home peak flow meter to help carefully measure the status of the disease and the responce to treatment (a peak flow meter is much more sensitive than just going by how you feel). For what it is worth, I am an Internal Medicine physician and treat lots of asthmatic patients many of which are athletes that are performing at high levels.