The Dawn Phenomenon

Blog, Wellness

Many people with diabetes observe that their numbers first thing in the morning are often higher than their target.  This condition is called “dawn phenomenon” and it can occur in people with type 2 diabetes. It’s best described as a high fasting blood sugar (FBS) number after waking in the morning. This puzzles and even alarms many people, especially when their blood sugar number the night before was in the right range for them, they have been following the meal and exercise plan set out by their doctor or diabetes educator and are taking their medications as prescribed.

What’s your A1c?

Before we delve into the dawn phenomenon though, it’s really important to emphasize that if your A1c is at or below your target, individual glucose numbers that are higher than your target aren’t a big deal. Your diabetes is still doing fine. If your A1c is above your target though, that’s when you really need to work with your doctor to figure out when your blood glucose is high and what to do about it. Figuring out how to address high morning numbers can be an important part of this process.

Why does this happen?

The science behind a high fasting blood sugar number has to do with a group of hormones that are released by the body during the night. All people, with or without diabetes, experience this as a part of the natural body cycle, or circadian rhythm. The hormones (including growth hormones, cortisol, glucagon and epinephrine) that are released sometime between 2 a.m. and 8 a.m. increase insulin resistance and cause blood sugar to rise. As you near waking time, the liver begins to release stored glycogen to give you the energy you need to get up and start the day. For a person without diabetes, the pancreas then reacts to this glycogen by appropriately releasing the correct amount of insulin to keep blood sugar in the normal range and still give the body the energy it needs to start the day. But if you have type 2 diabetes and are already insulin-resistant, this is where the problem is – the amount of insulin produced is not enough to balance out the glycogen and so you get a high blood sugar number in the morning.

What should I do?

If your morning blood sugar numbers are high, the first thing you need to do is talk with your doctor or diabetes educator. No one solution fits all people, so consider this a team project, especially if you are taking any medications. You’ll need to experiment to see exactly what helps you. A diabetes support group or online community can be a great place to discuss this with others who have experienced dawn phenomenon and get some suggestions and ideas from them. Many people find that having a small protein snack like nuts or cheese before bed helps while others may need to eat dinner earlier or have some activity after the evening meal. There may need to be an adjustment to the type, dose or timing of an evening medication or insulin. It would be great if there were a simple way to determine the cause and fix it, but it can take several weeks of trial and error to arrive at the answer so you’ll need to be patient – and persistent – as you and your doctor try to find the solution that works for you.

“Be sure to eat breakfast if your fasting blood sugar number is high in the morning.”

After you’ve done your fasting blood sugar test in the morning, go ahead and eat something even if your number is high. It seems counterintuitive that eating will bring the number down, but it works for many people. You’re sending a signal to your liver that you’re up now and ready to fuel your body with food so the liver can stop releasing glycogen. Breakfast is an important meal for anyone with diabetes, but especially so if you’re experiencing the dawn phenomenon.

Keep Track of Your Numbers

If you’re not sure if what you are experiencing is the dawn phenomenon, your doctor may ask you to use your meter to test at about 2 a.m. or so for a few nights to rule other causes such as nocturnal hypoglycemia (also known as rebound hypoglycemia) or the Somogyi Effect (more common in Type 1). Keeping a logbook while you’re trying to determine the cause can be very helpful.  

High morning FBS numbers can cause a lot of frustration and concern for someone with type 2 diabetes, especially if this suddenly begins to happen after years of good results. Keep in mind that with diabetes, things can change over time. That’s why you need to stay educated, keep testing, and have a good team that includes your doctor, diabetes educator and if possible, a support group.

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