Exercising with Asthma

I have exercise induced asthma. It makes for exercising a little bit more difficult. Sometimes my legs can keep going, but my lungs are screaming STOP! I have an inhaler and try to remember to take it with me when I go anywhere, but sometimes it gets left behind. I these occasions, there is no way I can go running, so I try to do stretches instead. I did try to go running up in Beaver without it, and because of the cold (34 degrees) and the wind, and the fact that I forgot my inhaler, I made it about 1/4 of a mile and thought I was going to collapse there on the spot and die. I may be a tad over dramatic about it, but breathing is one of those things that I feel should always happen. So do you have asthma? What do you do if you can't run?