Causes of High Blood Sugar in the Morning...

...and how you can treat it

Joy PapeBy Joy Pape, RN, BSN, CDE, WOCN, CFCN

Do you ever find that your blood sugar levels are higher when you wake up in the morning even though you didn't have anything to eat all night? If so, you are like a lot of people who have diabetes. But you may still be wondering, "Why?"

Early morning highs can happen in people with both type 1 and type 2 diabetes. The rise is connected to your insulin – whether you make it or take it – along with some other hormones and causes. Other names for early morning highs include: the dawn effect, Somogyi effect, and plain old early morning hyperglycemia.

To get a grip on this phenomena, let's learn more about insulin and other hormones that fight against your insulin to raise your blood sugar levels, and how your body reacts to low blood sugar.


  • is a hormone that is secreted by the beta cells of your pancreas, or is taken by injection (needle and syringe, insulin pen, or insulin pump).
  • is secreted or taken in response to your blood sugar levels. For example, if a person does not have diabetes, there is always a small amount of insulin secreted by one's pancreas to keep blood sugar in a normal range.  This is called background or basal insulin. After eating, when blood sugar rises, the release of insulin also rises to bring the blood sugar to normal levels. This is called mealtime insulin. For people who do have diabetes, many take two types of insulin to manage their blood sugar. One is a long-acting insulin such as NPH, Lantus (glargine), or Levemir (detemir) for their basal insulin, taken usually once or twice a day. The other, a mealtime insulin, is either a rapid-acting insulin such as Novolog (aspart), Humalog (lispro), or Apidra (glulisine), or regular insulin. Mealtime insulin is taken before eating and to correct or bring down high blood sugars. People who use insulin pumps most often use the rapid acting insulin in their pumps.
  • works on your liver to stop or decrease the amount of sugar your liver makes, especially at night. If you don't have enough insulin to stop or slow this process, your blood sugar may be high in the morning.
  • works on your blood, muscle, and fat cells to absorb sugar from your blood for energy. If you don't have enough insulin to stop or slow this process, your blood sugar may be high in the morning. 

Hormones that raise your blood sugar levels

  • Glucagon is a hormone secreted by the alpha cells of your pancreas. It raises blood sugar. When someone does not have diabetes, glucagon works in concert with insulin to help keep blood sugar in the normal range. It is considered a counterregulatory hormone to insulin. For example, if one's blood sugar starts to fall, glucagon will be secreted to raise it to normal levels. Many people who do have diabetes may still secrete glucagon in response to a low blood sugar. Some people do not have this response and need to take a glucagon injection if their blood sugar gets too low. Glucagon makes the liver release its stored sugar into the blood to raise blood sugar. If you don't have enough insulin to counteract glucagon, you may wake up with a high blood sugar.
  • Other hormones. There are other hormones known as counterregulatory hormones that "fight" against your insulin. Some of these hormones such as growth hormone, cortisol, and catecholamines work harder in the wee hours of the night and early morning. They can cause your blood sugar to rise if you don't have enough insulin to fight back.

How your body reacts to low blood sugar.

Everybody's diabetes is different. If your body is still able to respond to a low blood sugar, you will feel symptoms of a low blood sugar, which you should then treat. Some people treat a high by eating or drinking too many carbohydrates, so their blood sugar then gets higher than their target range. When you are sleeping, your body may not recognize a low blood sugar. This would be considered a type of hypoglycemia unawareness. In this case your body may respond by releasing glucagon to work on your liver to release the stored sugar and raise your blood sugar. It sometimes raises it higher than your target range, so you will wake up with a high blood sugar.

What you can do to lower your early morning highs

  • Know that although insulin can treat early morning highs, it can also cause early morning highs.
  • Understand the type of insulin you are taking. Know its onset, peak, and action times.
  • Check your blood sugar about 2 or 3am, to see if your body is responding to a low blood sugar. If so, you may need less medicine/insulin. If it is high, you may need more.
  • Consider using an insulin pump so your insulin can be adjusted to manage your early morning highs.
  • Check out dLife's slide show, Handling Morning Highs: Somogyi Effect vs. Dawn Phenomenon
  • Discuss your numbers with your health care provider so together you can come up with a plan that works to get your morning blood sugars into your target range.


Read Joy's bio here. 

Read more of Joy Pape's columns.

NOTE: The information is not intended to be a replacement or substitute for consultation with a qualified medical professional or for professional medical advice related to diabetes or another medical condition. Please contact your physician or medical professional with any questions and concerns about your medical condition.


Last Modified Date: December 15, 2014

All content on is created and reviewed in compliance with our editorial policy.
  1. Brown University. Insulin/Glucagon. (Accessed 11/13.)
  2. eMedicineHealth. Dawn Phenomenon and the Somogyi Effect. (Accessed 11/13.)
  3. Endocrine Web. Normal Regulation of Blood Glucose. (Accessed 11/13.)
  4. Medscape. Dawn Phenomenon Affects Half of Type 2 Diabetes Patients. (Accessed 11/13.)
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