Why is my blood sugar so high when I wake up? How to lower morning blood sugar

Katherine Isacks, MPS, RDN Registered Dietitian

It doesn't seem fair, does it? How come you need to lower morning blood sugar when you haven't eaten anything all night? What is going on? For those of you with diabetes, read on to learn how to get those morning blood sugar spikes in check.

How to lower morning blood sugar levels and what's going on overnight

Your body strives to keep blood sugar within a safe range. But with diabetes, the balance is disturbed. The insulin your pancreas produces might not be adequate to lower your blood sugar. In addition, body cells might not appropriately handle the insulin produced. And to make matters worse, your liver might be on glucose production overdrive. All of this results in your body's failure to control blood sugar overnight as well as after meals or snacks. For more information about diabetes, read Diabetes Basics at MyNetDiary.

Dawn phenomenon

Due to normal daily changes in our body's release of hormones during sleep and wake cycles, blood sugar typically starts rising very early in the morning–about 3 AM–and continues to rise as the morning progresses. For people without diabetes, insulin production simply increases, taking care of the rising blood sugar. However, for those with diabetes, unless medication is on board to cover this early morning rise, blood sugar will eventually rise out of target range by the time they wake up.

Suppose you have noticed that your fasting blood sugar is creeping up over time and is no longer within target range despite sticking to a carb-controlled eating plan and taking your diabetes medication as prescribed. Then it might be time to talk with your doctor about your diabetes medication. The type, dose, and/or timing might need to be adjusted to lower morning blood sugar. The recommended fasting target range is typically 80-130 mg/dL, but ask your healthcare provider what is right for you.

Keep thorough records of your blood sugar, food/beverages, exercise, and diabetes medication use. Include an accurate time stamp for all of these logs. If you use MyNetDiary, print out your reports and bring them to your appointment. If you and your provider are linked with MyNetDiary’s Professional Connect, your provider can easily review your records and offer advice on how to lower morning blood sugar within MyNetDiary. Please see Tracking Diabetes with MyNetDiary for more information.

Somogyi effect

Did you know that a high fasting blood sugar can be caused by experiencing hypoglycemia (blood sugar < 70 mg/dL) in the middle of the night? It is called the Somogyi Effect. Hypoglycemia can occur from too much insulin, too few carbs, too much alcohol, and/or extra exercise. When hypoglycemia occurs, the body releases extra hormones that increase blood sugar production. The typical pattern is this: blood sugar within target at bedtime, low in the middle of the night, and then high by morning. You might want to set an alarm to test your blood sugar in the middle of the night to rule this out. If this is happening to you, please see your healthcare provider as soon as possible. Hypoglycemia is unsafe, and being asleep can reduce a person's ability to detect it. Also, not everyone wakes up when they experience hypoglycemia.

Ate too much the night before?

A high carbohydrate snack in the evening may also increase your fasting blood sugar in the presence of insulin resistance. In addition, a large late-night, high-fat dinner can delay digestion and carb absorption of the meal enough so that your post-meal rise in blood sugar goes like gangbusters around the time the Dawn Phenomenon is kicking in.

Need help controlling carbs at meals? You can start with a typical goal of 30-45 grams of total carbs/meal if you are an adult woman or 45-60 grams/meal if you are an adult man. Try limiting your bedtime snack to 11- 20 grams of total carbs. Discuss personalized meal and snack goals with your healthcare provider. If you have diabetes, ask your doctor for a referral to a Certified Diabetes Care and Education Specialist (CDCES). This specialist is trained to help people manage all aspects of their diabetes care, including how to lower morning blood sugar.