When I exercise alot, I get better.  We are all different, and I know this does not work for most people here, but the rashes stop and my reactions are less severe when I do this.  (This did not work for me when I had a full blown masto rash though.)

There are some exercises that make me worse, like if there is alot of compression it can trigger a migraine.  I don't run.  Pushing to go really hard can cause a reaction, but this summer I rode my bike over 2,000 miles.  Sometimes I rode up to 80 miles in a day.  And the heat does not hurt me.  The more I sweat the better.  I am doing hot yoga since it is winter.  Hot yoga is between 1 and 1.5 hours in a studio that is +100 degrees.  Yoga is the most boring excersize IMO.  Biking is the most fun.  (Got the epi just in case.)

I am usually the first person in the room to feel cold.  In the winter, I really bundle up.  In the summer, I don't really get too hot like everyone else.