You're taking your medications as prescribed and you're keeping an eye on your carbohydrates, yet there still may be times when your blood sugar is too high. There are many reasons for blood sugar surges--I'd like to zero in on two common issues: high morning sugar and sugar that's high after exercising.
Waking up to high sugar
You'd think that your blood sugar should be lower after a night's sleep. After all, you haven't eaten anything for many hours. But the body needs glucose 24 hours a day, and if you're not getting it from food, your body will turn to stored glucose in the liver. Your pancreas needs to make insulin to deal with this glucose, just as it does for glucose derived from the food you eat. Unfortunately, in many people with diabetes, insulin production during periods of fasting is as meager as (or worse than) during eating. Therefore, the sugar may rise overnight because glucose being produced by the liver is not matched by adequate insulin from the pancreas. Also, certain medications, including glyburide (brand name Micronase or DiaBeta), glipizide (brand name Glipizide) and glimepiride (brand name Amaryl), improve meal-related insulin production more than fasting insulin production. As a result, many people who take these medicines have higher glucose levels in the morning than before bed at night.
Sometimes a bedtime snack will actually help lower morning blood glucose, because the sugar (from the carbohydrates in your snack) that hits your bloodstream causes the body to release more insulin than the sugar your liver releases during the night while you're fasting. Ideally, your snack should contain protein, some healthy fat and a slowly absorbed carbohydrate, such as two teaspoons of peanut butter on a half-slice of stone-ground whole-wheat bread. If this doesn't work, using a long-acting form of insulin as part of the treatment is usually very effective.