Susan B. Sloane, BS, RPh, CDE, has been a registered pharmacist for more than 20 years and a Certified Diabetes Educator for more than 15 years. Her two sons were diagnosed with diabetes, and since then, she has been dedicated to promoting wellness and optimal outcomes as a patient advocate, information expert, educator, and corporate partner.

We try hard to get it right, but sometimes our blood sugars get away from us. The trick is to figure out why we have a high number so that we can fix the problem. 

Yes, I know all too well this can be easier said than done, and in fact on some days there is no rational explanation for a random high blood sugar. But let's explore some ways we can understand blood sugar readings in the morning and how we can gain better control.

One of the most common causes of high morning blood sugars is excess glucose production from the liver. Our bodies were built with some internal mechanisms for creating balance. Since we are in a fasting state while we sleep, we can run out of fuel or energy by morning. 

The liver stores fuel in the form of glucose and will put out more glucose overnight to help the body stay balanced and to prevent hypoglycemia. For patients with diabetes, this excess glucose production, sometimes referred to as the “dawn phenomenon,” can cause high morning blood sugar readings.

Now that we understand one of the causes of high fasting blood sugars, we need to know how to treat this. One of the most common drugs used to treat diabetes is Metformin. This drug works by keeping the liver from producing too much glucose. This often helps patients with type 2 diabetes and is generally well tolerated. Metformin can cause some stomach issues and is often associated with weight loss, which can be a bonus.

Another possible cause of high morning blood sugars is hypoglycemia in the middle of the night. So, low blood sugar causes high blood sugar? Now I’m really confused, you say!

I know it sounds crazy, but let me explain. Your body really does actively try to maintain a balance in every way possible every minute of the day. If you have a really low blood sugar at 2:00 a.m. for example, your internal sensors try to keep blood sugars up as best they can. The liver goes into action pushing glucose out in an attempt to regain balance. The resulting rush of glucose into the bloodstream of a patient with diabetes causes—you guessed it—hyperglycemia.

The way we can prevent this condition, otherwise known as the “somogyi effect,” is by periodically checking blood glucose between 2:00 and 3:00 a.m. to determine if we see a trend of low blood sugars. 

Other causes of early morning low blood sugars may be not eating enough at dinner, exercise without adequate snacking, or possibly even a new drug added to your regimen that may cause low blood sugar. 

If you take basal insulin such as Lantus or Levemir, fasting blood sugars can be affected by them, and dosing may need to go up or down depending on you blood glucose readings. 

Keep in mind that exercise can also affect blood sugars for up to 24 hours or more, and that exercise that you recently add to your routine will affect blood sugars. You may need to decrease your insulin or medication dose or increase food intake as directed by your healthcare team. 

Stay safe and healthy!