Diabetes: The Dawn Phenomenon


Some of you may be familiar with this situation…You wake up to elevated blood sugar readings which were much higher than when you went to bed the night before. But you didn’t eat anything during the night that would cause this to happen right? High morning blood sugars are usually caused by the dawn phenomenon or the “dawn effect”. It is a common issue in diabetics, whether they are type 1 or type 2. This can often lead to frustration in those trying desperately to control their blood sugars daily.

So what exactly happens in the body to cause the dawn phenomenon? First off, it’s important to note that EVERYONE whether they have diabetes or not experiences the dawn phenomenon. It occurs when there is a surge of hormones, such as human growth hormone, cortisol, or epinephrine, in the early morning hours. These hormones tell the liver to secrete glucose which helps supply the body with energy in order to get us up in the morning. Those who have normal insulin response adjust to this changes in the body allowing the excess glucose to be utilized by cells in the body and results in consistently normal levels of glucose in the blood. Diabetics do not have these normal insulin responses. When the liver produces excess glucose in the morning hours, the pancreas is unable to keep up with insulin secretion to match the amount of glucose pouring into the bloodstream resulting in higher than normal glucose levels.

What can you do to fix this problem and better manage your blood sugar levels? First determine if the problem is actually a cause of the dawn phenomenon or if it something else. Keep in mind, this experiment is best done on the weekend or when you do not need to work the next day.

  1. Test your blood sugar just before going to bed and record it.
  2. Test your blood sugar in the middle of the night (sometime between 2 am – 4 am) and record it.
  3. Test your blood sugar first thing when you wake up in the morning and record it.

Do this for 2-3 days. They do not have to be consecutive days, but make sure you feel well and are not sick. Once you have your data, do you notice any trends? If what you are experiencing is the dawn phenomenon, you should see a significant spike in glucose from the second check to the third check but not so much from the first check to the second check.

What can you do? First you need to know what is triggering it:

Not consuming a bedtime snack – If your last food consumption is dinner around 6-7pm and you go to bed at 10-11pm, this might be the problem. Some people need that bedtime snack but without additional carbohydrates. Try having 1 oz of cheese paired with 1 oz of almonds as a bedtime snack in this case. On the other hand, if you experience a low blood sugar during the second check but then your third check is higher, this is known as the Somogyi effect, which is less common. In this case, try having a balanced snack (protein + 1 serving of carbohydrates) 1-2 hours before going to bed.

You need a basal insulin or other medication adjustment – Sometimes when medication is taken too early, it can wear off before you wake up resulting in a higher morning glucose. Discuss with your doctor or diabetes specialist about taking your medication dose just before you go to sleep to help counteract elevated morning blood sugar readings. You may also need less medication, a different type, or to take it at a different time. Any of these situations should be discussed with your doctor. Please do not attempt to adjust these medications on your own.

For most people, what can be done that morning, when glucose is high, is to make sure you have a balanced breakfast with less carbohydrates than usual (1-2 servings less depending on your glucose reading) to avoid a further increase. The first meal in the morning tells the body that it’s awake and it can stop producing the extra glucose and improve insulin sensitivity. It’s important to note that everyone’s bodies are different when it comes to how their blood sugars react. By checking your glucose readings daily and as instructed by your doctor or diabetes specialist, you can use this as a tool to better manage your diabetes and prevent future complications from elevated blood sugars.

New to diabetes? Want to know how you can self-manage your blood sugars? Make sure you are monitoring your carbohydrate intake. By following a low carbohydrate diet, you can control symptoms caused by a high or low reading and prevent future health complications. Discussing your diet with a dietitian and/or certified diabetes educator can get you on your way to a healthier you.