We definately increase our daughter's cortef for sports.  When she plays soccer on hot days we triple her meds.  Otherwise she overheats; we've had one episode that led to vomiting.  We use gatorade too, but the times we don't up the dose she becomes lethargic with headache, etc.  I personally can't stand the soccer because the whole time I'm anxious she will overheat.  It's a very competitive travel team (she's 10 1/2).  I have never upped her dose for swim team, but wonder.  She comes home tired from practice (85 laps), but I figure that's normal.  Our endo says not to limit her that by tripling, gatorade, etc. she should be able to participate like others but I have my doubts.  As Kay said the coaches become very demanding as the kids get older.  We have been subtly trying to push swimming and rec tennis over the soccer.