Why Is My Blood Glucose Level Higher When I First Wake Up?

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About 23.6 million people in the United States have diabetes. People with diabetes do not produce enough insulin, or their cells do not recognize insulin. Insulin moves glucose, your main source of energy, from your blood into your cells. Without insulin, glucose builds up in your blood and leaves your body through your urine. This means that your body loses its main source of fuel, which your body needs to function properly. If you have diabetes, you may notice that your blood glucose levels are higher when you first wake up. This can occur for a few reasons.

Blood Sugar Background

If you have diabetes, you need to keep your blood sugar levels as close to normal as possible, says the Cleveland Clinic. This means monitoring your blood glucose levels at home. There are many serious problems that can arise from glucose levels that are too high or low, says the "Journal of Clinical Endocrinology and Metabolism.” These include heart disease, stroke, blindness, kidney disease and nerve damage. According to MedlinePlus, monitoring your blood sugar will help you to see patterns in your levels, potentially alerting you to the fact that your levels are high in the morning.

Dawn Phenomenon

The dawn phenomenon is the name for high blood sugar levels in the early hours of the morning. The American Diabetes Association notes that this takes place whether you have diabetes or not, but it is especially noted if you check your blood sugar levels every morning. It is attributable to natural body changes that occur while you sleep. When you are in your deepest sleep, usually between midnight and 3 a.m., your body has little need for insulin. According to the Cleveland Clinic, any insulin you take during the evening causes your blood sugar levels to drop sharply at this time. Between 3 a.m. and 8 a.m., your bedtime dose of insulin is starting to wear off and your body also starts to release stored glucose in preparation for your day ahead and hormones that make your body less sensitive to insulin. This combination of events means high blood sugar levels when you wake up.

Somogyi Effect

Also known as rebound hyperglycemia, the Somogyi effect is due more to poor diabetes management than the natural causes of the dawn phenomenon, says the Cleveland Clinic. In some cases, taking too much insulin earlier in the evening, or not having enough of a bedtime snack, causes your blood sugar to dip too low during the night. This results in your body releasing hormones to try to raise your sugar levels, leading to high levels when you awake. Alternatively, if your dose of long-acting insulin at bedtime is not enough, you may also have high blood sugar levels in the morning.


In order to determine if your high morning blood glucose levels are due to the dawn phenomenon or the Somogyi effect, your doctor will most likely ask you to check your blood sugar levels between 2 a.m. and 3 a.m. for several nights in a row. If your levels are consistently low at this time, you most likely are experiencing the Somogyi effect. If your levels are normal or high, there is a greater chance that your high levels are due to the dawn phenomenon.


The right treatment for you depends on what your blood sugar levels are at night. Your doctor may suggest that you change the time that you take your evening dose of long-acting insulin, change the type of insulin that you take before bed, take extra insulin overnight, increase your morning dose of insulin or switch to an insulin pump, which will release additional insulin in the morning. Your doctor may also suggest that you do not eat a carbohydrate snack at bedtime, or eat a lighter breakfast.