Headaches are a common complaint at doctor appointments, can occur for many reasons, and can range in severity. For example, too much or too little sugar in the blood causes large swings in blood glucose and may contribute to headaches.
Glucose (sugar) is an important part of your body’s chemistry because sugar directly affects your brain and nervous system. Keeping your blood glucose within the normal range can help you prevent headaches.
What Types of Headaches Are There?
There are more than 150 kinds of headaches, each categorized as primary or secondary.
- Primary headaches: clinical diagnoses, so there is no blood test or imaging study to diagnose these. Some primary headaches can be caused by lifestyle factors, including drinking alcohol, consuming certain foods, using nicotine, lack of sleep, poor posture, or skipping meals.
- Secondary headaches: considered a symptom of a condition and usually subside when the underlying condition is treated. Possible secondary headaches include blood sugar, dehydration, sinus, or medication overuse headaches.1
What Is Hypoglycemia?
Hypoglycemia, also called low blood sugar or low blood glucose, occurs when the glucose level in your blood drops below normal limits. A blood glucose level lower than 70 milligrams per deciliter (mg/dL) indicates hypoglycemia.2
Hypoglycemia is often seen in people with type 1 diabetes; however, low blood sugar can occur in anyone, including healthy individuals or people with type 2 diabetes. Symptoms of hypoglycemia range from mild to severe, depending on blood sugar readings.3
Symptoms of low blood sugar include:
Mild low blood sugar symptoms (54 - 69 mg/dl)
- Nervousness and shakiness
- Excessive hunger
- Dizziness, lightheadedness, nausea, and/or headache
- Blurred vision
Moderate low blood sugar symptoms (< 55 mg/dl)
- Inability to concentrate
- Confusion and irritability
- Slurred speech
- Muscle twitching
- Mood swings
Severe low blood sugar symptoms (< 40 mg/dl)
- Loss of consciousness
Can Low Blood Sugar Cause Headaches?
Headaches caused by low blood sugar are often described as a dull, throbbing feeling in the temples. Low blood sugar headaches may occur with other hypoglycemic symptoms, like blurred vision, elevated heart rate, nervousness, fatigue, irritability, and confusion.4
Low blood sugar may also trigger migraine headaches. Migraine patients often report carbohydrate cravings right before the headache hits, which might be the body’s way of regulating blood sugar to prevent migraines.4
The usual migraine symptoms like nausea, vomiting, and sensitivity to light and sound might not accompany migraine headaches caused by low blood sugar. Instead, the migraine is more likely accompanied by the hypoglycemia symptoms noted above.
Treatment for Hypoglycemia Headaches
The first step for treating headaches is to determine the underlying cause. If headaches occur frequently and seem to be tied to significant fluctuations in blood sugar, it’s best to seek medical advice to discuss treatment options.
Primary headaches might be treatable with over-the-counter (OTC) medications, including acetaminophen and ibuprofen. However, headaches due to hypoglycemia are treated based on blood sugar readings.
The American Diabetes Association recommends that a blood glucose reading of less than 70 mg/dl be treated with 15 grams of simple carbohydrates.
Sources of 15 grams of simple carbohydrates include:
- 4 ounces (1/2 cup) of juice or regular soda
- 1 tablespoon of sugar, honey, or corn syrup
- Hard candies, jellybeans, or gumdrops—refer to the food’s label for serving size
- Glucose tablets
- Gel tube
Glucose level should be rechecked after 15 minutes, and if the reading is still below 70 mg/dl, the process should be repeated until a reading above 70 mg/dl is obtained. This is called the “15-15 rule.”
When treating a low blood sugar headache, the carbohydrate source is important. Complex carbohydrates (like whole grains) or foods with fats and carbs (like chocolate) can slow glucose absorption and will not effectively treat hypoglycemia.5 Severe hypoglycemia is a life-threatening medical condition and cannot be treated with the 15-15 rule. It requires a more aggressive method of treatment administered by someone other than the person with hypoglycemia.
For those who do not live with hypoglycemia, glucagon could be used to treat a low blood sugar headache. Glucagon is a hormone produced in the pancreas that stimulates the liver to release stored glucose into the bloodstream when blood glucose levels are too low. Glucagon is also used by those living with diabetes when their blood glucose is too low to treat using the 15-15 rule.
Glucagon is available by prescription and either injected, administered, or puffed into the nostril. If you are concerned that your headaches may be caused by low blood sugar, consult your medical provider to determine whether a glucagon product is appropriate for you and how and when to use it.5
How to Prevent Headaches Caused by Hypoglycemia
Swings in blood sugar may cause headaches, whether from hypoglycemia or hyperglycemia. Eating a well-balanced diet and practicing other health-promoting habits may help you prevent the side effects of low or high blood sugar. Some sustainable habits to try to incorporate into your lifestyle include:
The CDC recommends adults participate in at least 150 minutes of moderate-intensity physical activity plus two or more days of muscle-strengthening activity per week.6
Eat balanced meals and snacks, and don’t skip meals
Avoid eating meals that only contains carbohydrates. When preparing a meal or snack, aim to balance carbohydrates, protein, and dietary fat. Protein and dietary fat slow digestion, which helps prevent spikes in blood sugar. Balanced meals and snacks help you feel full and satisfied for longer, which helps to prevent blood sugar lows.7
Eat consistent meals and snacks throughout the day. Avoid skipping meals, as waiting too long to eat can cause drops in blood sugar, which may cause a low blood sugar headache. Eating every three to four hours is a good way to keep blood sugar levels stable and within normal range.
Drinking alcohol causes an increase in insulin secretion, which can lead to low blood sugar. Limit alcohol intake and avoid drinking on an empty stomach.8
Nicotine can increase blood sugar levels and make it hard to keep within normal limits. Additionally, smoking has many other negative health consequences, including cancer, heart disease, stroke, lung diseases, diabetes, and chronic obstructive pulmonary disease (COPD).9
Keep yourself hydrated
Drinking enough water may help keep blood sugar levels within healthy ranges. In addition to preventing dehydration, it allows your kidneys to flush out excess sugar through urine.
Improve stress management
Physical and mental stress can trigger the release of adrenaline and cortisol into the blood. These hormones can cause blood glucose levels to rise. Over time, extreme shifts in blood glucose levels may negatively impact health. Finding ways to manage your stress can improve your blood glucose response.11
Get enough sleep
Inadequate or poor-quality sleep can negatively impact your body’s ability to keep blood sugar within normal ranges. Aim for at least eight hours of quality sleep each night.12
Limit sugar intake
Limit added sugar intake to less than 10 percent of daily calorie intake. Eating large quantities of sugar in one sitting may temporarily increase your blood sugar levels.
Additionally, consuming excess sugar may increase fat storage in the body. This can cause insulin resistance and metabolic syndrome, and impair the body’s ability to maintain healthy blood sugar levels.
Try replacing sugar-sweetened foods and drinks with items that contain no added sugar, like a piece of fruit or water with a squeeze of lemon juice. That can help you decrease your intake of added sugars.
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Topics discussed in this article:
- Ahmed F. Headache disorders: differentiating and managing the common subtypes. Br J Pain. 2012;6(3):124-132. doi:10.1177/2049463712459691
- Cryer, PE, et al. Evaluation and Management of Adult Hypoglycemic Disorders: An Endocrine Society Clinical Practice Guideline. J Clin Endocrinol Metab 94:709-728, 2009.
- Burt Solorzano C, Topiwala S, Maraka S. Severe hypoglycemia. Endocrine Society. https://www.endocrine.org/patient-engagement/endocrine-library/severe-hypoglycemia. Published March 31, 2022. Accessed December 29, 2022.
- Hypoglycemia. National Headache Foundation. https://headaches.org/hypoglycemia/. Accessed December 29, 2022.
- Hypoglycemia (low blood glucose). Hypoglycemia (Low Blood Glucose) | ADA. https://diabetes.org/healthy-living/medication-treatments/blood-glucose-testing-and-control/hypoglycemia. Accessed December 29, 2022.
- How much physical activity do adults need? Centers for Disease Control and Prevention. https://www.cdc.gov/physicalactivity/basics/adults/index.htm. Published June 2, 2022. Accessed December 29, 2022.
- Basturk B, Koc Ozerson Z, Yuksel A. Evaluation of the Effect of Macronutrients Combination on Blood Sugar Levels in Healthy Individuals. Iran J Public Health. 2021;50(2):280-287. doi:10.18502/ijph.v50i2.5340
- van de Wiel A. Diabetes mellitus and alcohol. Diabetes Metab Res Rev. 2004;20(4):263-267. doi:10.1002/dmrr.492
- Grøndahl MF, Bagger JI, Lund A, et al. Effects of Smoking Versus Nonsmoking on Postprandial Glucose Metabolism in Heavy Smokers Compared With Nonsmokers. Diabetes Care. 2018;41(6):1260-1267. doi:10.2337/dc17-1818
- Carroll HA, Templeman I, Chen YC, et al. Effect of acute hypohydration on glycemic regulation in healthy adults: a randomized crossover trial. J Appl Physiol (1985). 2019;126(2):422-430. doi:10.1152/japplphysiol.00771.2018
- Sancini A, Ricci S, Tomei F, et al. Work related stress and blood glucose levels. Ann Ig. 2017;29(2):123-133. doi:10.7416/ai.2017.2139
- Tiwari R, Tam DNH, Shah J, Moriyama M, Varney J, Huy NT. Effects of sleep intervention on glucose control: A narrative review of clinical evidence. Prim Care Diabetes. 2021;15(4):635-641. doi:10.1016/j.pcd.2021.04.003