Doxycycline
Primatene mist is one of those medicines that really annoy doctors and every now and then they try to get the FDA to remove it from the market. The reason is that it's basically aerosolized epinephrine and as such, it frequently speeds up the heart and drives up the blood pressure. A much better medication is available by prescription (meaning you have to see your doctor) - it's albuterol and it doesn't affect heart rate and blood pressure nearly as much as Primatene. So the Primatene mist WILL help your symptoms while you're exercising BUT you'll end up with a double whammy - heart rate and blood pressure will increase because of the exercise and will increase still further because of the Primatene!

JAN
I use albuterol sparingly as it raises my normally low blood pressure to a too high level. You may have to see what works best for you. After almost ten years the only thing that helps me is oxygen. I was always short of breath when I exercised too. It is very frustrating to be able to climb those steps and feel like you hit a wall at the top. I have found that if I make a conscious effort to regulate my breathing when I am active I do better. It is almost as if I am unconsciously holding my breath while exercising to save oxygen and it back fires. I do not know if you understand what I mean, but if you are having the same feeling try to take charge and remember to breath. Breath in from your abdomen, not the upper chest too. Breathing correctly is important too.

My4tress
I've used Primatene when I was a child for a number of years. It helps relieves symptoms, but overally I became immune to it (or it just lost its effectiveness, I dunno). Either way, you're better off going to a doctor or clinic for asthma & allergy to have your asthma treated properly. They will be able to prescribe medication that is most effective for you while giving you more tips for specific treatment.