What Causes High Morning Blood Sugar?

Jul 27, 2020

Does this sound familiar?

You’ve had a great day, Diabetes-wise, making healthy choices about activity and food and your blood sugar has been in range all day. When you head to bed a few hours after dinner your blood sugar is a nice 112. Super proud of yourself, you expect to FINALLY wake up with a fasting blood sugar you can be proud of. The next morning, you brush your teeth and take your morning meds before pulling out the blood glucose meter, already proud of what you know will be a fantastic result. 162.

WTF??? This is not the result you were expecting. You went to bed at 112, had nothing more to eat, got a great night’s sleep and now your blood sugar is HIGHER? What gives?

High fasting blood sugar is one of the more frustrating aspects of Type 2 Diabetes. It’s also an incredibly common scenario. Personally, I got so frustrated at this perceived failure that most of the time I’d “forget” to take my fasting blood sugar because it was NEVER in range, no matter WHAT I did. No one ever told me WHY this was happening so I thought it must be something I was doing wrong. It's the thing my doctor focused on the most but  she never mentioned that it's a common issue for people with Type 2 Diabetes. I felt like such a failure. 

Now I know better. 

There are two major reasons why fasting blood sugar is often the highest blood sugar of the day. One reason is a “feature” of Type 2. The other applies both to people with Type 1 and Type 2.

Just about everyone with Type 2 Diabetes struggles with “The Dawn Phenomenon” or “Dawn Effect.” Due to a complex combination of naturally occurring hormones, the liver is stimulated to produce glucose.

In the “Adding Insult to Injury” department, our bodies actually MAKE glucose, no matter how good we might be at limiting the sugar we consume.

This early morning phenomenon (sometime between 2 a.m. and 8 a.m., depending on your body’s natural cycles) occurs in everyone. People without Diabetes don’t get a blood sugar rise because they appropriately produce insulin to cover this glucose surge.

The primary hormone that induces the liver to release sugar is glucagon. In people without Diabetes, glucagon and insulin work in balance to maintain the blood sugar in a narrow range. One of the problems for people with Type 2 Diabetes is that they have overproduction of glucagon, causing the liver to release glucose along with insulin resistance that causes the body to be unable to efficiently use the glucose, and, often, an inadequate insulin response. All this creates a perfect storm for morning high blood sugar. 

What can you do about this?

The primary way to improve high fasting glucose caused by the Dawn Phenomenon is to work on improving insulin resistance. This is one of the places where you can really see the benefit of the lifestyle changes to treat Diabetes. Significantly cutting carbohydrates gives the body less glucose to process. Moderate daily activity also decreases insulin resistance.

Many of the medications for Type 2 Diabetes work on both insulin resistance AND reduce the output of glucagon, which in turn reduces the glucose produced in the liver.

Basically, the things you do to improve your overall Diabetes wellness can also improve your morning blood sugar.

The second cause of high morning blood sugar (following a normal evening blood sugar) is called the Somogyi Effect. Unlike the normal physiological cycle of the Dawn Effect, the Somogyi Effect is usually caused by some breakdown in Diabetes management.

Somogyi Effect happens when blood sugar goes very low, causing a protective release of glucagon that causes a rebound high blood sugar. This is different than the Dawn Effect because it is a reaction to a low blood sugar and causes a larger release of glucagon and a resulting higher spike in blood sugar. This sets up a blood sugar roller coaster that can continue throughout the following day.

What causes that middle-of-the-night low in the first place?

As mentioned above, it’s usually caused by some sort of breakdown in Diabetes management. For people with Type 1 Diabetes, it’s usually about adjusting timing of long- and short-acting. For people with Type 2 Diabetes, it can also be about adjusting medication, but also may be related to what you eat at night, particularly prior to bed. This is something you’d need to talk with your medical provider about.

Here are a few suggestions about where to start:

  • Determine if your morning highs are caused by Dawn Effect or Somogyi Effect. This can be done by measuring very early morning blood sugar to rule out middle-of-the-night lows. You can do this by wearing a continuous glucose monitor or by setting an alarm to wake up and check your blood sugar a few times in the middle of the night.
  • If you determine that the highs are caused by Dawn Effect, the best way to deal with this is to double down on lifestyle efforts to treat your insulin resistance. Remember that this is a physiological response that happens to everyone, even healthy people. For most people with Type 2 Diabetes, the fasting blood sugar is the last measurement to get under control.
  • If you determine that the highs are caused by Somogyi Effect, your medical team may need to adjust your medication to prevent nighttime lows. You can help prevent nighttime lows by avoiding high-carb snacks prior to bed and adding a high-protein/high-fat snack that can help you maintain your blood sugar throughout the night. The most important thing about managing Somogyi Effect though is to have your health care provider help you manage the nighttime lows that can be dangerous!

High fasting blood sugar can be frustrating, but I think it’s comforting to know that it’s something that just about everyone with Diabetes struggles with, and that many medical providers (right or wrong) focus on.

Remember that you’re more than your numbers!



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