What Causes High Glucose Levels: Learn About Hyperglycemia

Hyperglycemia, or high blood sugar, is often a cause of diabetes as well as stress, illness, and other factors.

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by
April Benshosan
— Signos
Health Writer
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Reviewed by

April Benshosan
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Updated by

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Science-based and reviewed

Published:
February 5, 2024
November 27, 2023
— Updated:

Table of Contents

Ebbs and flows in your blood sugar levels are completely normal. But if you often find that your blood glucose dramatically spikes when you haven't even eaten yet, then you may have hyperglycemia. Also known as high blood sugar, hyperglycemia is a tell-tale sign of diabetes — and requires treatment. Taking insulin and other diabetes medication that helps stabilize blood sugar can help keep your hyperglycemia under control and prevent serious health complications.

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What is Hyperglycemia?

Simply put, hyperglycemia is a condition characterized by too much sugar, or glucose, circulating in the blood. The prefix "hyper" means "high," while "glycemia" refers to blood glucose. Also, hyperglycemia shouldn't be confused with hypoglycemia, low blood sugar levels (aka the opposite of hyperglycemia). 

Hyperglycemia occurs when the body is unable to produce enough of the hormone insulin, which controls blood sugar and keeps levels stable. It can also occur if one has insulin resistance, a condition in which the body does not effectively use insulin. 

So, what's considered "high" when it comes to blood sugar? Fasting blood glucose levels that creep up above 125 mg/dL (milligrams per deciliter) are considered high, and that's usually an indication of type 2 diabetes. If your fasting blood sugar levels are a little lower, around 100 mg/dL to 125 mg/dL, then that may suggest you have prediabetes. 

People living with type 1 diabetes or type 2 diabetes either don't produce enough insulin or have insulin resistance, which is why they often experience episodes of hyperglycemia. If left untreated, high blood sugar can lead to serious health problems, such as life-threatening diabetes-related ketoacidosis (DKA), as well as nerve and kidney damage and eye disease.1,2

What Causes High Glucose Levels?

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Most often, not taking your insulin correctly (like skipping doses or not taking the right amount of insulin) can cause high glucose levels when you have diabetes. But other, lesser-known triggers can also contribute to high blood sugar levels.

Causes of high glucose levels may include but are not limited to:

Stress

Whether emotional or physical, stress can cause blood sugar levels to spike as the body releases the stress hormone cortisol. High cortisol levels can reduce your body's production of insulin, a hormone secreted when blood sugar levels get too high. Traveling, exposing yourself to high temperatures (think: sitting in a sauna), being dehydrated, and engaging in intense exercise can all put your body under stress and potentially lead to high blood sugar levels.

Illness and Infection

Having a cold or another illness or battling an infection puts physical stress on your body and can contribute to hyperglycemia. Stress causes your body to produce more cortisol and adrenaline, hormones that can spike blood sugar levels.

Dehydration‍

Being dehydrated causes the sugar in your blood to become more concentrated, spiking your blood glucose levels. Rehydrating with water or other drinks can help add fluid to your blood. It can also help you excrete some extra sugar through your urine, diluting the sugar in your blood and bringing your blood glucose levels back down to a healthy range. 

Taking Certain Medicines

Some medications can cause your blood sugar to hit levels higher than normal. These meds include steroids, glucocorticoids, clonidine, hormonal contraceptives, and amiodarone. If you're on medication and experience spells of high blood sugar, speak with your doctor or healthcare team about whether the meds you're on may be contributing to these blood sugar spikes. 3,4

Symptoms of High Glucose Levels

Depending on how high your blood sugar levels are, symptoms can range from uncomfortable to life-threatening. Usually, though, you'll start noticing symptoms of hyperglycemia once your blood glucose levels reach levels over 180 mg/dL.

Some early symptoms of high glucose levels include:

  • Increased thirst
  • Frequent urination
  • Fatigue
  • Headaches
  • Trouble concentrating
  • Blurred vision

Having chronically high levels of blood glucose — like if diabetes is left untreated — can lead to more serious complications. These serious symptoms can include:

  • Vaginal and skin infections
  • Slow-healing wounds
  • Poor vision
  • Nerve damage
  • Painful, cold feet or loss of feeling in the feet
  • Erectile dysfunction
  • Chronic constipation, diarrhea, or other GI issues
  • Blood vessel damage
  • Kidney disease

If hyperglycemia is left untreated, it could lead to a life-threatening condition called diabetic ketoacidosis or diabetic coma. This occurs when your body doesn't have enough insulin and can't access glucose for energy, so instead, it breaks down fats for energy in a process that produces chemicals called ketones. Too many ketones in the blood can cause your blood to become acidic, leading to symptoms such as feeling faint or blacking out, fruity-smelling breath, fast heartbeat, trouble breathing, and confusion. Diabetic ketoacidosis requires immediate medical attention.5

How is Hyperglycemia Treated?

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If you live with diabetes, it's super important to treat your hyperglycemia so that it doesn't develop into more serious complications down the line. While hyperglycemia can be treated by taking insulin and other glucose-lowering medications, you'll also want to implement certain lifestyle changes. 

Treatments for hyperglycemia include but are not limited to:

Drinking More Water 

When blood glucose levels are high, your blood is more concentrated with sugar. Drinking more water can help dilute the sugar in your blood, leading to lower blood glucose levels. 

Exercising More

Making regular movement part of your routine can help lower your blood sugar and keep it in check. Exercising can also help you lose weight, which has its own glucose-stabilizing effects.

Changing Eating Habits

Your healthcare provider may suggest limiting carb-rich foods, especially those high in refined and added sugars. Work with a dietitian to figure out an eating plan that can help reduce blood sugar spikes and works with your lifestyle. 6,7

How to Prevent High Glucose Levels

To keep your blood sugar under control and prevent hyperglycemia, you will need to make some necessary lifestyle changes and possibly take medication. 

Some ways to prevent high glucose levels in the first place include: 

  • Sticking to a nutritious, blood-sugar-regulating meal plan
  • Adding exercise to your routine
  • Testing your blood sugar regularly
  • Managing your stress levels and getting enough sleep
  • Drinking enough water throughout the day

Learn More About How to Improve Blood Sugar Health with Signos’ Expert Advice

If you have hyperglycemia, working with your doctor to choose the right medication can aid in weight loss if you have obesity or overweight and help you manage your diabetes — and ultimately improve your health. And managing your blood sugar levels can be made easier with Signos' continuous glucose monitors (CGMs). 

Signos keeps tabs on your blood sugar levels throughout the day and allows you to track everything you eat and drink, which gives you insight into what affects your blood glucose levels. To learn even more about managing your diabetes and keeping your blood sugar levels in check, read through Signos’ blog.

Ready to try CGMs? Take this quick quiz to find out if Signos is right for you.

Discover how to live well with diabetes with the help of Signos wearable CGM. Ebbs and flows in your blood sugar levels are completely normal. But if you often find that your blood glucose dramatically spikes when you haven't even eaten yet, then you may have hyperglycemia. Also known as high blood sugar, hyperglycemia is a tell-tale sign of diabetes — and requires treatment. Taking insulin and other diabetes medication that helps stabilize blood sugar can help keep your hyperglycemia under control and prevent serious health complications.


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References

  1. Cleveland Clinic. (2020, February 11). Hyperglycemia Signs, Treatment & Prevention | Cleveland Clinic. Cleveland Clinic; Cleveland Clinic. https://my.clevelandclinic.org/health/diseases/9815-hyperglycemia-high-blood-sugar
  2. Mayo Clinic (2022, August 20). Hyperglycemia in Diabetes - Symptoms and Causes. Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/hyperglycemia/symptoms-causes/syc-20373631
  3. Kamba, A., Daimon, M., Murakami, H., Otaka, H., Matsuki, K., Sato, E., Tanabe, J., Takayasu, S., Matsuhashi, Y., Yanagimachi, M., Terui, K., Kageyama, K., Tokuda, I., Takahashi, I., & Nakaji, S. (2016). Association between Higher Serum Cortisol Levels and Decreased Insulin Secretion in a General Population. PLOS ONE. https://doi.org/10.1371/journal.pone.0166077
  4. Tosur, M., Viau-Colindres, J., Astudillo, M., Redondo, M. J., & Lyons, S. K. (2020). Medication-induced hyperglycemia: pediatric perspective. BMJ open diabetes research & care, 8(1), e000801. https://doi.org/10.1136/bmjdrc-2019-000801
  5. Hyperglycemia (High Blood Glucose) | ADA. (n.d.). Diabetes.org. https://diabetes.org/living-with-diabetes/treatment-care/hyperglycemia
  6. Hyperglycaemia (high blood sugar). (n.d.). NHS Inform. https://www.nhsinform.scot/illnesses-and-conditions/blood-and-lymph/hyperglycaemia-high-blood-sugar/#:~:text=eating%20too%20much%2C%20such%20as
  7. Centers for Disease Control and Prevention. (2019). 10 Surprising Things That Can Spike Your Blood Sugar. CDC. https://www.cdc.gov/diabetes/library/spotlights/blood-sugar.html

About the author

April is a writer, editor, and content strategist with a Master’s degree in Publishing.

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