Why is my blood sugar high in the mornings?

Have you ever asked this question to yourself “why my blood sugar or my glucose is high in the morning”? High blood sugars in the morning are a fairly common problem that a lot of diabetic patients face on a daily basis. In the morning, almost everyone experiences a slight increase in blood sugar levels. A person without diabetes will not necessarily realize this as a problem as their body can adjust. For a person with diabetes, however, high blood sugar/glucose in the mornings can be problematic, and it may need treatment.

On the other hand, high blood sugar in the morning is not always a problem or the only problem for every patient with diabetes. Because, if you are on medications like metformin or long-acting insulin such as Toujeo, Tresiba, Lantus blood sugar may end up being okay in the morning or even too low if taken too much which is an opposite problem. This happens because some of these medications work at night to help regulate blood sugars.

So why is the blood glucose/sugar high in the morning commonly in diabetics?

In most patients suffering from diabetes insulin resistance is the primary reason for elevated blood sugars in the morning. The dawn phenomenon and the Somogyi effect can also play a role( these will be discussed separately below). In addition to that, depending on the type of the patient, insufficient insulin, incorrect medication dosage, carbohydrate snacks before bed are common causes for morning high blood sugars (hyperglycemia).

Why would insulin resistance cause high blood sugar in the morning?

The liver produces glucose during a fasting state such as overnight fasting while sleeping. Insulin is the only main hormone that regulates glucose production through the liver. Basically, when insulin levels go down glucose production goes up. When insulin levels go up glucose production goes down. In an insulin resistance state, which is similar to an insulin-deficient state since the liver does not recognize the communication that insulin is trying to deliver. So, the liver in a diabetic patient will end up making too much glucose as insulin does not work efficiently enough to regulate blood sugar production through the liver.

Why is the blood sugar high despite taking medication?

Most medications to take in the morning forces your body to make insulin. So agents like glipizide produce insulin that helps with your meals. But then it wears off. And then at night your body still needs insulin. So insulin is not just necessary for the food, but also your body needs insulin even during fasting. Therefore, even if you’re eating no carbs whatsoever you still need insulin. In the relative deficiency or resistance to insulin, a lot of patients will end up waking up with high blood sugars especially if the medications they take wears off by the time they go to bed.

What to do to improve insulin resistance and reduce morning blood sugars/glucose levels?

There are ways you can do this. So number one and the best option is to do intermittent fasting, eating with portion control, exercising daily at least 30 minutes. If lifestyle changes are very difficult or not effective enough then we start discussing diabetes medications. Metformin or pioglitazone are too commonly prescribed medications for that purpose to defeat insulin resistance.

Which diet is the best to improve insulin resistance?

According to studies, no diet is superior to one another except the Mediterranean diet when it comes to weight loss and improving longevity. Because the Mediterranean diet has been studied multiple times and has been proven multiple times to reduce the heart attacks and strokes as well as reduce diabetes. Ketogenic diets have proven to be superior to other diets in terms of cardiovascular risk reduction. Although ketogenic diets can help prevent diabetes type 2. You should discuss your lifestyle changes and medications preferably with an endocrinologist.

What is the dawn phenomenon?

Morning hyperglycemia in diabetic patients may occur due to the dawn phenomenon. The dawn phenomenon occurs when insulin secretion decreases due to medications including insulin wearing off together with a physiological increase in insulin-opposing hormones. The most common hormones that causes the problem are growth hormone, cortisol. This is a physiological event and cannot be prevented. On the other hand, your endocrinologist can help you manage the condition.

What is the Somogyi effect?

The Somogyi effect is present in the case of patients taking an excessive amount of insulin or insulin-secreting oral diabetic medications. Due to the presence of excess insulin blood sugars can go too low during the time when the body is the most sensitive to the action of the insulin. This time is between midnight and 3 AM. The Somogyi effect happens if blood sugars go too low during these times which results in a rebound blood sugar spike. Low blood sugar events will trigger cortisol, growth hormone, and adrenalin response. This hormonal response will trigger a rebound high blood sugar.

On the other hand, the dawn phenomenon is more common than the Somogyi effect. To diagnose these phenomena, it is useful to measure plasma glucose levels for several nights between 3 a.m. and 5 a.m. or use a continuous glucose monitoring system. If blood sugar is low around 3 AM such as 60 mg/dL, high blood sugars, and such as 200 mg/dL at 8 AM can be explained by the Somogyi effect. In this case, the endocrinologist will adjust medications in order to avoid this late night or early morning hypoglycemia (low blood sugar).

If blood sugars are somewhat high such as 150 mg/dL at 3 AM in the morning, the clinician can easily diagnose morning hyperglycemia (high blood sugar) such as 220 mg/dL as a result of the dawn phenomenon. Although their treatment differs, the best way of preventing both the dawn phenomenon and the Somogyi effect is an optimal diabetes control with insulin therapy.

What can you do to avoid the dawn phenomenon?

Since the dawn phenomenon is simply an exaggeration of insulin resistance due to hormones such as growth hormone presence of an already high blood sugar definitely exaggerates the problem. I recommend my patients to avoid carbohydrates at bedtime. I also sometimes adjusted their medications such as their insulin. Patients who are on insulin pumps are easier to manage when it comes to the dawn phenomenon. That is because insulin pumps and allow insulin delivery adjustments hour by hour.

Also, some insulins are better than others when it comes to long-acting insulin. Sometimes we switch patients to Tresiba or Toujeo. Tresiba and Toujeo are typically longer acting basal insulins compared to Lantus and Levemir. Occasionally I will advise the patient to change the time of the insulin administration. For example, if somebody is taking Levemir in the morning, it may not be lasting an entire 24 hours till the next morning. In this case, taking Levemir in the evening may be an alternative approach to control the dawn phenomenon and morning high blood sugars better.

Ahmet Ergin, MD, FACE, CDCES, ECNU
Endocrinology

West Palm Beach, Florida

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