Overview

The dawn phenomenon can cause high blood sugar levels, especially in the morning before breakfast, in people who have diabetes.

The dawn phenomenon is a normal rise in blood sugar as a person's body prepares to wake up.

• In the early morning hours, hormones (growth hormone, cortisol, and catecholamines) cause the liver to release large amounts of sugar into the bloodstream. For most people, the body produces insulin to control the rise in blood sugar.
• If the body doesn't produce enough insulin, blood sugar levels can rise. This may cause high blood sugar in the morning (before eating).

If you have diabetes and your blood sugars are often high in the morning, talk to your doctor. Your doctor may need to adjust your medicines.