Your Blood-Sugar Level Drops During Exercise

This level will go even lower if you have a lot of insulin in your blood. However, you need some insulin circulating in your blood or, in response to exercise, your liver will make more glucose, causing your blood-sugar level to rise.

Check your blood sugar before you exercise. If it's low, you can drink a sugar-containing beverage. If it's high, you can take a small dose of regular (or lispro) insulin.

If it is higher than 300 mg/dl, we recommend that you delay exercise until the insulin you have taken lowers your glucose to less than 250 mg/dl. The more intensely you exercise, the more difficult it is to predict whether your blood sugar will increase or decrease.

If you exercise for a long time, recheck your blood sugar halfway through. With experience, you will learn to predict how your exercise will affect your blood-sugar levels. You may notice a blood-sugar lowering effect for as long as 24 hours after heavy exercise.