My daughter is 13 and a non-salt-waster.  She has participated in sports since she was 5.  She used to play soccer when she was little, now it is basketball, softball, and horseback riding.  She loves to swin recreationally - no team swimming for her.  Anyway, heat is a VERY BIG stressor.  She had to stop basketball last year after two practices because the coach ran then continuously for 2 hrs at the practices (literally).  I had to stress dose her after each practice.  I spoke to the endo about this just last week.  This was a new dr - her old one retired - but was in the same practice.  She agreed with me that we should give extra hydrocortisone (Cortef or equivalent) BEFORE the game or practice and hydrate BEFORE, DURING, and AFTER the event.  A salty snack BEFORE has been recommended as well.  My daughter also perspires more than "normal" from any physical activity and from the heat.  I am convinced this is part of  her CAH.  We try to encourage physical activity as much as possible to help with weight control (also healthy eating).  We find that if Kristin is going to do physical things, we have to be proactive with the medication and fluids.   We will also monitor the activities closely now that she is older and everything is more competitive and therefore practices tend to last longer and be more physically challenging.