swimming is seen as a very good way to strengthen the lungs and may be of benefit to anyone with asthma.
Also, as pegleg has said [The more you understand asthma, the easier it will be for you... ]
Find out what the allergies are, I only found out in my early 20's what actually triggered off my attacks, it wasn't the dust of feathers I'm alergic to, it was something my body produces during exercise.
once i knew this It made things easier
hope this may be of some use
Diagnosed June 2005 with Crohns (left colon, large bowel)
Diagnosed Osteopenia Feb 2006
Asthma since childhood
changed my style to silver
changed my clothes to black