I have a 5th grader who had a pre meal BG of 454, ate his lunch of 73 carb gms (after getting 5 units of Novalog insulin per parents instruction). He was to run a timed mile run in gym class immediately after lunch. I instructed not to run. I did not check for ketones because the blood sugar was so high, that it seemed to preclude any exercise. But I have not found much documentation of blood sugar levels and holding exercise, just the presence of ketones? Any input into this situation?