Why are you not supposed to exercise when you have ketones?

Positive ketones means one is burning stored fat. This could be a good thing if obese, but, in diabetes terms, usually means insulin is not enough to allow proper energy to be utilized and thus the reserve energy (fat stores) are being used. They could be from an infection or could just be not enough insulin for the amount of food. If ketones are positive and exercise occurs, then, by definition, there is insufficient insulin for the muscles to use and they must send a signal to raise the blood glucose level. However, the glucose cannot go into the muscles since there is still not enough insulin and thus the switch to burning the fat. So, the body signals to make more and more glucose and sometimes this makes the blood sugar even higher and more out of control. So, in the presence of high ketones, don’t exercise; fix the insulin deficiency problem. A good source for more information is the book The Diabetic Athlete by Sheri Colberg.

SB