The dawn phenomenon is a term that describes an unexpected rise in blood sugar during the night. It is believed that hormones released during sleep send a message to the body to release stored glucose. This in turn raises the concentration of sugar in the blood. This rise in overnight glucose is often a source of confusion and frustration for people with diabetes and occurs more often in people with type 1.
Eliminating a bedtime snack and checking your blood sugar during the night (around 3 a.m.) will help you and your doctor assess whether high morning glucose readings are the result of the dawn phenomenon or something else.
Kaufman, F.R. The Dawn Phenomenon. American Diabetes Association. Retrieved November 21, 2008. http://docnews.diabetesjournals.org/cgi/content/full/3/7/5