Why Does My Blood Sugar Go Up During The Night?

Blood sugar levels and sleeping habits are intricately associated with each other. Often it can be found that when you go to bed, your blood sugar or glucose level in the blood is around 110 or less; while it rises up to 150 when you wake up in the morning. Despite not eating anything during the night or while you are asleep, this blood sugar fluctuation and rise during night is a common phenomenon that is normally referred to as the Dawn Phenomenon or the Dawn Effect.

About Blood Sugar:

The body requires energy to perform all sorts of physiological tasks. It gets this energy from glucose or carbohydrate that is available in the food that we eat. The carbohydrate is digested and the glucose is absorbed into the bloodstream where it is converted into energy particles through a prolonged process. A part of this glucose is stored into the liver (storage of energy) for later usage. The glucose in the bloodstream gives the blood sugar amount that is measured through a sugar test.

Why Does My Blood Sugar Go Up During The Night?

The blood sugar level can sometimes go up during the night for some people. The possible reason for it could be two:

The Dawn Phenomenon:

Now that we have a general idea of how blood sugar works, it is important to know about dawn phenomenon. While the body requires energy to do all the physiological tasks, it also requires energy to wake up in the morning, to start the day and to keep on performing the physiological tasks even when you are asleep. The sleeping time is a prolonged period of fasting in which the body is not supplied with any carbohydrate or glucose to perform the internal bodily functions. However, the body doesn’t stop doing its functions.

Hence, to perform these bodily functions or physiological tasks, the body releases its stored glucose from the liver and starts churning it out. This is usually the time between 3 a.m. and 8 a.m. It is because of this reason that the blood sugar level in the morning is found to be higher than at night.

Along with this, the role of insulin must also be mentioned here. The liver releases only as much glucose as is required. To tell the liver about the requirement or how much glucose is needed to the body, there is a hormone that functions and it is called insulin. In some cases (patients with type 1 diabetes), there is not enough insulin that can communicate with the liver about the right amount of glucose that is required. That is the reason why the liver continues releasing glucose and as a consequence, the blood sugar level is high.

In case of type 2 diabetes, the patients have enough insulin, but the insulin cannot communicate with the liver regarding the amount of glucose that needs to be released, the blood sugar level may go up high. This can happen any time of the day. However, if the patient is on diabetes medicine, during early morning, the effect of the medicine would wear off and then, the liver will release more glucose than what is needed.

The Somogyi Effect Causing Blood Sugar Level to go up During the Night:

There is another possible reason behind the high blood sugar levels in the morning or blood sugar levels that go up through the night and that is, the Somogyi Effect. When a person has too low blood sugar levels, which is possible for hypoglycaemia patients, the body sends signals to the liver through the hormones to release more glucose into the blood for performing the bodily functions. It is the body’s own way of ‘rescuing’ itself from the adverse effects of low blood sugar, which is usually the inability to produce energy and perform the physiological tasks. When this release is extremely high, more than what is needed or more than usual, it is called the Somogyi Effect. It is named after Dr. Michael Somogyi, who first discovered this condition and the reason behind this. It results into high blood sugar levels in the morning.


These are the two basic reasons behind why the blood sugar levels go up during the night or early in the morning. Sometimes people blame their previous night dinner for this condition. However, it is rarely the case and most of the time it is the dawn phenomenon that is to blame. Eating breakfast is the best solution to reduce this increased blood sugar level if dawn phenomenon is the cause behind this. This is because, eating breakfast signals the body that it is morning and the body it getting enough food and thereby, the liver stops releasing the stored glucose. This reduces the blood sugar level naturally.

Also Read:

Pramod Kerkar, M.D., FFARCSI, DA
Pramod Kerkar, M.D., FFARCSI, DA
Written, Edited or Reviewed By: Pramod Kerkar, M.D., FFARCSI, DA Pain Assist Inc. This article does not provide medical advice. See disclaimer
Last Modified On:August 21, 2018

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