If you have diabetes, there are three reasons why your blood sugars may be higher first thing in the morning. Conditions known as the dawn phenomenon or dawn effect, the Somogyi effect, or waning insulin may cause your blood sugars to be elevated first thing in the morning, even if they tend to be relatively stable at bedtime, according to Diabetes Forecast, published by The American Diabetes Association. Of the three, waning insulin is probably the easiest to correct.
Dawn Phenomenon
One cause of high blood sugar in the morning may be the dawn effect or dawn phenomenon. During the night, your body releases hormones including epinephrine, glucagon, cortisol and growth hormone, according to Mayo Clinic. These hormones cause your blood sugar to rise. The release of these hormones also inhibits your body's muscle and fat cells from using insulin to effectively carry sugar from your blood into your cells.
The Liver
Your liver releases small amounts of sugar when you are not eating, especially at night, according to Diabetes Forecast. If you have diabetes, the amount of sugar released by your liver during the night is too much for your cells to take up. This is particularly true because your body is producing hormones that hamper the effectiveness of your insulin. If your blood sugars are well controlled before bedtime but consistently high first thing in the morning, you may be experiencing the dawn effect. Treatment for the dawn phenomenon varies among individuals with diabetes.
Somogyi Effect
The Somogyi effect occurs when your blood sugar drops too low while you are sleeping. The Symogyi effect can be the result of insufficient food intake, alcohol consumption or too much insulin. To counteract the drop in your blood sugar, your body produces hormones that cause your liver to produce sugar. When you have diabetes, your liver overreacts by producing excess sugar. If your blood sugar is low at 3 a.m., it's probably due to the Somogyi effect. The end result of the Somogyi effect is a high fasting blood sugar.
Waning Insulin
If your insulin wears off during the night, your morning blood sugar will be high. Your doctor can help you adjust your insulin dosage or the timing of when you take your insulin. If you check your blood sugar at bedtime, 3 a.m. and first thing in the morning and find that it's higher at 3 a.m. than it was before bedtime and higher still first thing in the morning, your insulin is likely waning.
