When recently meeting with our diabetes team, we were told that exercise during the presence of ketones in the urine is dangerous. Is this so? If so, why?

Ketones are an “alternative fuel” during the metabolism of body fat. The issue of ketosis is that excessive ketones can “build up” and lead to the dangerous, and possibly fatal, DKA [diabetic ketoacidosis] which can cause brain swelling and usually is associated with severe nausea and vomiting.

Heavy, hard, exercise, can lead to a degree of acid production, and if there is not adequate sugar, can also be associated with a degree of ketosis for fuel. So the concern is that if someone already has some ketosis, exercise may be “too much for the body to handle.” Frankly however, I think people have to use common sense. If there is only a trace or small ketones, then I generally do not restrict my patients from having fun with general play/activities/exercise. I ask them to assure hydration. If they are very competitive athletes on the basketball or soccer or water polo team (or other games that don’t have built-in pauses, like football or baseball), then I think ketones should be pretty much cleared before heavy participation.

Other pediatric endocrinologists may feel differently about this. You should abide by the directions of your diabetes team.

DS