In reply to Jim Braid: My asthma is pollenish, so might work a bit differently. First, I moved to Scotland where there is no Summer. Secondly, I use a brown inhaler, which manages things superbly. Lastly, if things are very bad, I warm up without drugs until the wheeze starts, then use the blue inhaler. That normally controls it. Funnily enough, if I take the stuff mid exercise, the wheeze never properly goes away.
I also have a blue inhaler in every rucksack I use!