Can High Blood Sugar Cause Headaches?
If you’ve ever had a headache and wondered if your blood sugar might be the cause, you’re not alone. Many people living with diabetes or insulin resistance report headaches during blood sugar spikes. But what’s really happening in the body—and how concerned should you be?
This guide explains the connection between high blood sugar (hyperglycemia) and headaches, what symptoms to watch for, and how to manage them.
What is high blood sugar?
High blood sugar, also called hyperglycemia, happens when there is too much glucose in your blood. This can be caused by:
● Eating more carbs than usual
● Skipping insulin or medication
● Stress, illness, or infections
● Hormonal changes
A fasting blood sugar level over 130 mg/dL or a random reading above 180 mg/dL is considered high.
If you're struggling to manage spikes, this guide onhow to monitor glucose levels at home can help you stay on track.
Can high blood sugar cause headaches?
Yes, high blood sugar can cause headaches. It’s not the most common symptom, but it happens—especially when blood sugar stays elevated for hours or days.
Why it happens:
When blood sugar rises, it pulls water and electrolytes out of your cells. This can cause dehydration, which is a known trigger for headaches. Inflammation and changes in blood vessels may also play a role.
For a deeper understanding of what your levels mean, check out thisblood glucose level chart for ketosis.
What do high blood sugar headaches feel like?
The pain may feel like:
● A dull, throbbing ache
● Pressure behind the eyes
● General tension across the forehead
Headaches from high blood sugar often come with other symptoms, like:
● Increased thirst
● Fatigue or drowsiness
● Blurry vision
● Trouble concentrating
● Frequent urination
Everyone’s experience is different. Some people feel fine even with high numbers. Others may notice symptoms at slightly elevated levels.
If you've ever experienced dizziness or fatigue after meals, exploredizziness after eating and diabetes.
How high does blood sugar need to be to trigger a headache?
There’s no exact threshold. Some people get headaches when levels are just slightly high—say, 180 mg/dL. Others don’t feel symptoms until blood sugar climbs above 250–300 mg/dL.
Chronic high blood sugar (above 200 mg/dL consistently) is more likely to cause symptoms than short spikes.
Ever wonder why your fasting blood sugar is high but A1C is normal?This article breaks it down.
Is it a headache from high or low blood sugar?
This can be tricky. Both high and low blood sugar can cause headaches.
High blood sugar headache:
● Develops gradually
● Comes with thirst, dry mouth, fatigue
Low blood sugar headache:
● Comes on quickly
● May include shakiness, sweating, dizziness, irritability
The only way to know for sure is to check your blood glucose. If you’re unsure, test before you treat.
What helps a high blood sugar headache?
If your headache is caused by high blood sugar, the best way to treat it is to lower your glucose safely.
Try the following:
● Drink water to stay hydrated
● Go for a walk or light activity (if safe)
● Take insulin if prescribed and needed
● Avoid sugary foods until blood sugar stabilizes
For pain relief, acetaminophen or ibuprofen can help—but always check with your doctor first.
If blood sugar stays high or you develop nausea, vomiting, or confusion, seek medical attention. These may be signs of diabetic ketoacidosis (DKA), a medical emergency.
Learnwhat to drink to lower blood sugar immediately without risking a crash.
How to prevent blood sugar-related headaches
Managing your blood sugar can reduce the risk of headaches. Try to:
● Stick to a consistent meal schedule
● Avoid large, high-carb meals
● Monitor your glucose regularly
● Take your medications as prescribed
● Stay active and hydrated
Tracking your symptoms along with blood sugar readings can help you spot patterns.
If you’re looking for reliable tools, consider using ablood sugar test kit for daily management.
Talk to your doctor if:
● You have frequent headaches
● You’re not sure what’s causing them
● Your glucose is often high despite treatment
● You’re experiencing symptoms of DKA (nausea, fruity breath, confusion)
Don’t ignore frequent headaches. They may signal poor glucose control or other health issues.
Still unsure if diabetes is a disability?This guide can help you understand your rights and options.
Takeaway
Yes, high blood sugar can cause headaches—especially when levels stay elevated for long periods. These headaches are often dull and come with other symptoms like fatigue or thirst. The only way to know for sure is to check your blood glucose.
Lowering your blood sugar safely, staying hydrated, and following your care plan can help reduce these headaches. If you have frequent or severe pain, talk to your healthcare provider.
Worried about blood sugar headaches? Use ourblood sugar tracking tools or subscribe to our newsletter for personalized tips and updates.
Related Resources
● Why Is My Fasting Blood Sugar High but My A1C Is Normal?
● What to Drink to Lower Blood Sugar Immediately
● Blood Sugar Test Kit: A Complete Guide
References
Headache: What it is, types, causes, symptoms & treatment. (2017, August 23). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/9639-headaches
Hyperglycemia (high blood sugar). (2023, September 6). Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/9815-hyperglycemia-high-blood-sugar
Hyperglycemia in diabetes. (n.d.). Mayo Clinic. Retrieved September 2, 2025, from https://www.mayoclinic.org/diseases-conditions/hyperglycemia/symptoms-causes/syc-20373631
Islam, M. R., & Nyholt, D. R. (2022). Glucose-related traits and risk of migraine-A potential mechanism and treatment consideration. Genes, 13(5), 730. https://doi.org/10.3390/genes13050730
Leonard, J. (2019, April 23). Diabetes and headaches: What’s the connection? Medicalnewstoday.com; Medical News Today. https://www.medicalnewstoday.com/articles/319770
Sugar headache: Causes, conditions, and prevention. (2020, June 2). Medicalnewstoday.com; Medical News Today. https://www.medicalnewstoday.com/articles/320464
Watson, K., & Rossiaky, D. (2017, July 10). Types of headaches: Symptoms, causes, treatments, and more. Healthline; Healthline Media. https://www.healthline.com/health/headache/types-of-headaches
