Why is Blood Sugar High in the Morning?

05/21/2021 | 6 min. read

Written by:

If you are unfamiliar with the way that blood sugar works, you may be surprised to find out that your blood sugar may be at its highest in the morning.

Basically, each time you eat, your body works to break down that food into sugar, and then the sugar gets sent into your blood. From there, insulin helps move the sugar from your blood and into your cells, where it is then used right away as fuel for energy or is stored for use at a later time.

So, if blood sugar rises when you eat because of the sugars from your food being sent into your blood, why might your blood sugar be high in the morning?

This kind of confusion is perfectly reasonable, and if you find yourself wondering why this might be the case, you are in the right place.

Causes of High Blood Sugar in the Morning

If you experience high blood sugar during the mornings, there are a few things that could be the cause.

In short, high blood sugar in the morning is caused by certain changes and reactions that are taking place in your body, so let’s get into some of the details.

The Dawn Phenomenon

The dawn phenomenon is one potential culprit for high blood sugar in the morning, and this happens in the early morning when certain hormones in your body, specifically cortisol and growth hormone, signal your liver to boost the production of glucose.

When this signal takes place, more glucose gets produced which then works to wake you up.

This triggers the beta cells in your pancreas to release insulin so that your blood glucose levels stay regulated, but with the dawn phenomenon, too much or too little insulin may be produced in order to counter the rise in blood sugar.

The dawn phenomenon is especially prevalent in those with diabetes, and occurs in about half of patients with either type of diabetes.

Waning Insulin

Another potential cause of high blood sugar in the morning is waning insulin, which happens if your insulin levels fall too low overnight while you are sleeping, thus leading to an increase in blood sugar levels.

This drop in insulin can be caused by different things for different people, but a common cause is an insulin pump with settings that provide too little background insulin during the night while you sleep, or if you have a long-acting insulin dose that is too low.

Insulin duration has to do with how long the drug takes to start working in your body, and this, too, comes into play. Injecting long-acting insulin into your body too early in the night may lead to it wearing off by morning.

The Somogyi Effect

Yet another possible cause of high blood sugar levels in the morning, the Somogyi effect has to do with the way your body responds to low blood sugar levels. The Somogyi effect is sometimes also referred to as rebound hyperglycemia, and it was named after the doctor who first wrote about it, Michael Somogyi.

Rebound hyperglycemia may happen if your blood sugar levels become too low in the middle of the night while you are asleep, and end up triggering the release of certain hormones in your body as an attempt to save you from the harmful effects of extremely low blood sugar.

The hormones that get released work to tell your liver to start releasing glucose that has been stored, and this glucose gets released in larger amounts than it usually does. Especially in people with diabetes, the liver releases more sugar than is necessary, and this leads to high blood sugar levels in the morning.

How to Figure Out What is Causing Your High Blood Sugar in the Morning

If you are noticing high blood sugar each morning, this is a sign that you should talk to your doctor to get to the root of the problem.

Your doctor will likely ask you to begin checking your blood sugar levels between 2 am and 3 am for a few nights in a row, and if your blood sugar is consistently low when you check it between these times, the Somogyi effect may be the culprit.

Alternatively, if your blood sugar is at a normal level when you check it in between these times, the dawn phenomenon may be a more likely cause. Regardless, your doctor will be able to work with you to figure out what is causing your high blood sugar in the morning.

If you are fairly certain that you already know what is causing your blood sugar levels to be so high when you wake up, it is still important for you to consult your doctor for a professional diagnosis.

How Can High Blood Sugar Levels in The Morning Be Treated?

There are a few different ways that high blood sugar levels in the morning may be treated, and it is important to consult your doctor in order to decide which method of treatment may be best for you.

If the dawn phenomenon is the cause, the following strategies might work, under the guidance of your healthcare provider:

  • Changing the timing of, or type of, your diabetes medications
  • Eating a lighter breakfast
  • Increasing the dose of your diabetes medications in the morning

For the Somogyi effect, the following may be effective, under the guidance of your healthcare provider:

  • Decreasing the dose of diabetes medication that may be causing low blood sugar overnight
  • Adding a carb-heavy snack before bedtime
  • Getting some evening exercise a little earlier than usual

Certain supplements may also help maintain healthy blood sugar levels, but these should not be used in place of professional treatment methods.

Before taking any vitamins or supplements, it is important for you to consult with your doctor.

It is especially important to talk to your doctor if you have underlying health conditions or are taking any other medications, as some medications may interact when combined, or may not be recommended for use by people with certain health conditions.

Your doctor can also advise you regarding what the best dose of a supplement may be, or they can work with you to come up with a plan about dosing if you have specific questions or concerns of your own.

The Bottom Line

If you are experiencing high blood sugar levels when you wake up, there are a few potential reasons why this may be happening.

The dawn phenomenon happens when your body tells your liver to start producing either too much or too little glucose in the morning to completely wake you up.

Usually, in the morning your body produces cortisol and growth hormone which then tell your liver to produce some glucose in order to wake you up, but if too much glucose is produced this is called the dawn phenomenon.

Waning insulin is another potential culprit for high blood sugar levels in the morning, and this happens when your insulin levels become too low overnight, thus leading to increased blood sugar levels.. Waning insulin can be caused by a few things, one of which is a dose of diabetes medication before bedtime that is too low, and thus does not last you until the morning.

The Somogyi effect is the third main cause of high blood sugar levels in the morning, and it entails your blood sugar levels becoming dangerously low throughout the night while you are sleeping, to which your body responds by telling your liver to release glucose that has been stored.

The glucose gets released in amounts that are too high, thus causing high blood sugar in the morning.

Whatever the case may be, your doctor can help you find the cause of your high blood sugar in the morning, and they will work with you to come up with a treatment plan for your individual needs.

Healthy Directions Staff Editor