This patient support community is for questions related to juvenile diabetes including
Celiac disease,
depression, diabetic complications, hyperglycemia /
diabetic keto-acidosis,
hypoglycemia, islet cell transplantation,
nutrition, parenting a diabetic child, pregnancy, pump therapy, school issues, and teens with
diabetes.
http://www.cnn.com/HEALTH/library/DA/00036.html
I think that the process of moving glucose into our cells (yes, still using insulin) is more efficient when we exercise (I'm about to get on the treadmill after reading this board!). Thus, all else equal, it takes less insulin to get the job done. Sugars are taken out of our blood to fuel the working muscles.
I generally turn down my pump by about 20%, leaving 80% of the basal. Sometimes that's right, sometimes I still get low or have to snakc, other times I'd've been fine leaving it alone. Mostly, however, 80% is my number. Given the activity profile of Humalog, I turn down my pump about 30 min before I start exercising and normally turn it back up (assuming I didn't fall too low) once I'm done.
For youngsters who are growing, I wouldn't be surprised if there were other considerations. I've long ago stopped growing, and this works well for me. I'm interested to look at that web site reference you were given, too.