Hypoglycemia and migraines

Very often people who get frequent headaches are labeled as having migraines. Sometimes they are migraines, and sometimes, they are not. One common cause of frequent headaches is hypoglycemia.

Has this ever happened to you? You’ve had a busy day, running around trying to complete many chores and keep important appointments, and it is now 3:00 in the afternoon and you feel a bit weak and dizzy, and have developed a dull throbbing headache. Then you remember, you only gulped down a cup of coffee before you ran out of the house this morning, and haven’t eaten anything all day. You know if you get something to eat quickly, you will feel fine. What is happening? This is a typical example of how hypoglycemia may feel and what can cause it.

What is hypoglycemia?

Hypoglycemia, or low blood sugar, is the medical term that describes the condition when a person’s blood sugar (glucose) level becomes too low, and causes numerous problems, including headaches. Glucose is an important fuel for the body. It primarily comes from eating foods that contain carbohydrates, such as bread, cereal, milk, fruits, and sweets.

Our body has a very intricate control system to keep our blood sugar levels at a very steady state. After a meal, glucose molecules are absorbed into your bloodstream and carried to your cells. Once the glucose molecules are in the cells they are used for energy. Insulin, a hormone produced by your pancreas, helps glucose enter the cells.

The most common cause for hypoglycemia is decreased food intake. People with diabetes have a medical condition that makes it difficult for their body to keep control over the proper amount of glucose in their blood. They will usually need to take a medication to help bring down their blood glucose level. If they take too much medication or have not eaten enough carbohydrates or other sources of sugar, their glucose level can go down very quickly, and they will experience hypoglycemia. There are other causes for hypoglycemia as well. Some people overproduce insulin when they eat carbohydrates, and this can lead to hypoglycemia. Certain other kinds of illnesses that result in abnormal hormone levels can also cause hypoglycemia.

Glucose is the primary fuel for the brain, so it makes sense that some of the first symptoms of hypoglycemia will result from its effect on the brain. Typical hypoglycemia symptoms are lightheadedness, weakness, throbbing headache and sweating. If your blood sugar dips low enough, you can even lose consciousness.

Are the headaches caused by hypoglycemia migraine headaches?

Headaches that are due to low blood sugar are not migraine headaches. You can usually figure this out if your headache goes away quickly when you have something to eat, especially if it’s high in sugar content, like a candy bar or orange juice. Headaches caused by hypoglycemia are quite common. If you have frequent headaches, hypoglycemia is an important cause to consider because the treatment for a hypoglycemia-caused headache is different from the treatment for a migraine headache. Unfortunately, many people in the United States who have frequent headaches never even see a doctor for them, may never receive the correct headache diagnosis, and then don’t get the appropriate medical treatment that they need.

How is hypoglycemia diagnosed and treated?

Talk with your health care provider if you think you may have hypoglycemia. Hypoglycemia may be diagnosed after a health care provider has taken a medical history and performed a series of tests to measure blood glucose levels over several hours. This is called a glucose tolerance test. Treatment may be as simple as changing the kinds of foods that are eaten every day, or eating more frequently. While it is normal for a person’s blood glucose to be at its highest level right after a meal, and at its lowest the longer it has been since the last meal, some people are more sensitive to low blood glucose levels than others. If you are very sensitive, you can usually handle this by eating small meals frequently, not going for a long time without a meal, and always carrying snacks when traveling.


Hypoglycemia is a diagnosis made by a health care provider after an examination and blood tests. However, symptoms of hypoglycemia are common, and often cause headaches. That is why people with frequent headaches should see their health care provider in order to get the correct diagnosis and know that they are getting the correct treatment.


MedLinePlus Health Information (2008). Hypoglycemia. Retrieved June 20, 2008 from www.nlm.nih.gov/medlineplus