Can Low Blood Sugar Cause Headaches?

By Sabina Rebis, MD
Medically reviewed checkmarkMedically reviewed
October 26, 2022

Key takeaways

  • Low blood sugar can cause headaches and other symptoms to occur suddenly.

  • Glucose that falls below 70 mg/dL counts as hypoglycemia. Hypoglycemia may occur as a result of medications used to treat type 2 diabetes.

  • Proper medication management, eating a healthy diet regularly and maintaining a consistent amount of physical activity are the best ways to prevent low blood sugar.

Low blood sugar is medically known as hypoglycemia. When blood sugar levels drop too low, it can cause many different symptoms, including headaches. In this article, you’ll learn about the diagnosis, treatment, and prevention of headaches relating to low blood sugar, as well as how to know when you should see a healthcare provider.

Can Low Blood Sugar (Hypoglycemia) Cause Headaches?

Hypoglycemia occurs when blood sugar levels fall below 70 mg/dL. They are often caused by imbalances in medications used to treat type 2 diabetes. Because the brain relies on glucose as fuel, low blood sugar can quickly become a serious condition that needs urgent medical attention. 

Low blood sugar can cause headaches and other symptoms. If you have type 2 diabetes and develop a headache, checking your glucose levels can identify whether low or high levels contribute to the headache.

If you take medication for type 2 diabetes and change your typical carbohydrate intake, and activity level, or don’t take your medication consistently, it can affect  blood sugar levels. .

Low blood sugar is not uncommon. Around half of those who take medication for type 2 diabetes may experience low blood sugar at some point.

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What Do Headaches from Low Blood Sugar Feel Like?

Headaches that are caused by low blood sugar happen because of changes to brain hormones like epinephrine and norepinephrine. These changes impact blood vessel dilation, which can increase blood flow mechanisms , resulting in dull or all-over head pain.

Other Symptoms of Hypoglycemia

Hypoglycemia can cause symptoms quickly. Besides headaches, other signs and symptoms of hypoglycemia can include:

Diagnosis

Low blood sugar is diagnosed if your glucose levels drop below 70 mg/dL. Hypoglycemia can happen occasionally, or it can happen frequently.

If you experience symptoms of hypoglycemia, it is important to let your healthcare provider know. If it becomes a recurring problem, it could mean that your diabetes medication is at too high of a dosage, your dietary plan needs adjustment, or your physical activity level has changed.

Some people who experience low blood sugar will only have it happen at night while they are sleeping. When blood sugar levels drop too low when you sleep, it can result in waking up from nightmares or being excessively sweaty. You could also wake up, unsure about what disrupted your sleep. If you take medication for type 2 diabetes or have been diagnosed with it, and you have disruptions to your sleep, testing your glucose levels in the middle of the night can help a medical provider understand whether hypoglycemia is to blame.

Treatment

Hypoglycemia is treated based on symptoms and other factors that are likely causing it. Treatment of  hypoglycemia may involve:

  • Adjustments to type 2 diabetes medication dosage
  • Maintaining a stable level of physical activity
  • Consuming a consistent combination of carbohydrates, proteins, and fats 

Other factors can also play a role in supporting normal blood sugar levels, such as drinking enough fluids, getting enough sleep, and finding healthy ways to manage stress.

If you only experience nighttime hypoglycemia, your medical provider may suggest a bedtime snack that contains a balance of carbohydrates and protein, like almonds.

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Prevention

When you are being treated for type 2 diabetes, especially if you take medication to lower blood sugar levels, it is important to make sure that you maintain a consistent healthy diet. Suddenly eating more or less can alter your blood sugar levels, especially if you reduce your carbohydrate intake.

Higher activity levels or intense exercise can use more blood glucose, which could lead to low levels if you take medication to keep your blood sugar low. If you want to increase your exercise intensity, work with your medical provider. They may need to monitor your blood sugar levels more closely, suggest consuming more carbohydrates before exercise or reduce your diabetes medication.

Preventing low blood sugar is possible by understanding what factors can cause your levels to drop. By regularly testing your blood sugar levels as directed by your medical provider, you can be aware of signs of hypoglycemia before you develop symptoms.

When to See a Medical Provider

If you experience episodes of hypoglycemia, you should let a medical provider know. This is especially important if you are on medications like metformin or others that lower your glucose levels.

If you are unsure how to maintain balanced glucose levels, your medical provider or healthcare team can help you understand diet, exercise, and other lifestyle management tips to support balanced blood sugar levels.

Treating Low Blood Sugar Online

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Frequently Asked Questions

What do low blood sugar headaches feel like?
Headaches that are caused by low blood sugar can feel like dull head pain, or may feel like throbbing in the temples (sides of the forehead). Head pain from low blood sugar may also include other symptoms, like feeling dizzy or lightheaded, having blurry vision, feeling hungry or irritable, or having a fast heartbeat.
How do you feel when your blood sugar is too low?
Low blood sugar can cause symptoms quickly, including blurry vision, headache, dizziness, hunger, rapid heart rate, and irritability. If it has been a long time since you last ate, and you take medication for type 2 diabetes, low blood sugar could be likely the cause of your symptoms. As many as half of patients treated for type 2 diabetes experience low blood sugar at some point.
What does a diabetes headache feel like?
Hypoglycemia occurs when blood sugar levels drop below 70 mg/dL. Low blood sugar can cause dull or throbbing head pain which may be felt at the sides of the head or all over. Changes to the blood vessel dilation in the brain from decreased glucose levels cause pressure changes, which can trigger head pain. Less commonly, very high blood sugar levels, known as hyperglycemia, can cause headaches, although it takes longer for high blood sugar to cause symptoms.
How do you stop a hypoglycemic headache?
If you have a low blood sugar headache, consuming some carbohydrates is important to help increase glucose levels. This could be done with glucose tablets, liquids, or gels, if available, but even fruit juice, fruit snacks, soda, or anything with simple carbohydrates can alleviate low blood sugar. You can also complement this with a glass of water.
K Health articles are all written and reviewed by MDs, PhDs, NPs, or PharmDs and are for informational purposes only. This information does not constitute and should not be relied on for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment.

Sabina Rebis, MD

Dr. Sabina Rebis is a board certified family medicine physician with over 5 years of primary care and urgent care experience.