What Is Hyperglycemia?

Hyperglycemia is high blood glucose (sugar) levels. It is common in people with diabetes. Insulin is a hormone made in the pancreas that helps keep blood glucose levels from getting too high. It may be prescribed to prevent or treat hyperglycemia.

Acute (short-term) symptoms of hyperglycemia may include increased thirst, urination, hunger, tingling in the hands and feet, and blurry vision that usually goes away after blood glucose levels return to normal.

This article reviews what hyperglycemia is; its symptoms, treatment, and complications; the self-management of blood glucose levels; what to eat with hyperglycemia; and when to seek medical treatment.

Blood drawn into tubes for testing on a tray

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Hyperglycemia Symptoms 

Symptoms of hyperglycemia can include:

  • Increased thirst
  • Frequent urination
  • Increased hunger
  • Blurry vision
  • Tingling in the hands and feet
  • Unintentional weight loss
  • Fatigue
  • Sores or cuts that do not heal or heal very slowly
  • Headache

Do Hyperglycemia Symptoms Mean Diabetes?

A variety of factors can contribute to hyperglycemia. Sometimes high blood sugar can occur without diabetes. In these cases, high blood sugar might be due to a chronic medical condition, a hormonal disorder, certain medications, or a result of a major illness.

Slightly elevated blood sugar levels may also indicate prediabetes, which can lead to the development of diabetes. If you have high blood sugar levels often or are experiencing symptoms of high blood sugar, it’s important to check in with a healthcare provider, as well as to monitor your blood glucose at home.

Frequent high blood glucose levels can increase the risk of developing diabetes and related complications later on. 

Hyperglycemia vs. Hypoglycemia

Hyperglycemia is when blood glucose levels are too high. Hypoglycemia is the opposite and occurs when blood glucose levels are too low. For most people with diabetes, this is a blood glucose level lower than 70 milligrams per deciliter (mg/dL), however, numbers may be different depending on the person. 

You are more likely to experience hypoglycemia if you have diabetes or take medication that can lower your blood glucose. Other risk factors for hypoglycemia include being over age 65 or having other health conditions, such as kidney disease, heart disease, or cognitive impairment.

Hyperglycemia Causes

There are several causes of hyperglycemia, which include:

  • Insulin resistance (when your cells don’t respond properly to insulin)
  • Reduced or lack of insulin production by the pancreas
  • Eating lots of highly processed foods with carbohydrates and saturated fats
  • Certain medications, such as corticosteroids, thiazide diuretics (water pills), some psychiatric medications, and certain human immunodeficiency virus (HIV) treatments
  • Genetic mutations
  • Hormonal diseases, such as Cushing’s syndrome or hyperthyroidism (overactive thyroid)
  • Damage or removal of the pancreas
  • Stress

In addition to diabetes, there are many other risk factors for hyperglycemia. A risk factor is not necessarily a cause but may contribute to the development of hyperglycemia. Risk factors for hyperglycemia are similar to those for type 2 diabetes. They include:

  • Being overweight or having obesity
  • Being 35 years old or older
  • Having family members with diabetes
  • Not being physically active on a regular basis
  • Having prediabetes
  • Having had gestational diabetes (diabetes that develops during pregnancy) or giving birth to a baby weighing 9 pounds or more

Type 2 diabetes is diagnosed more often in the United States in people who are Black, Native American, Asian American, Latinx, or Pacific Islander.

Hyperglycemic Attack: What to Do 

A hyperglycemic attack, sometimes called a diabetic attack, is when blood sugar levels spike. This can lead to a medical emergency if action is not taken to bring blood sugar levels back down.

Untreated hyperglycemia may lead to diabetic ketoacidosis (DKA), especially in people with type 1 diabetes (insulin-dependent diabetes, in which the pancreas makes little to no insulin), or hyperglycemic hyperosmolar syndrome (HHS)—which usually occurs in people with type 2 diabetes who do not have their blood glucose levels under control.

Insulin is one of the main treatments to lower blood glucose in hyperglycemic attacks. Doses are individualized and determined by a healthcare provider. If you do not take insulin, there are other medications that can help with lowering blood glucose levels. Contact a healthcare provider to see if an insulin or medication adjustment is needed.

In addition to medication, drinking plenty of water and moving your body (such as going for a walk) can help to bring blood glucose levels back down. However, if a person has ketones in their urine, they should not exercise as it can raise blood sugar further. Continue checking your blood glucose levels regularly to ensure they return to normal.

How High Is Too High?

Diabetes is a condition in which blood glucose levels are higher than normal, or hyperglycemic. A diabetes diagnosis is defined as:

  • 126 mg/dL or greater while fasting (not eating for at least eight hours)
  • 200 mg/dL or greater without regard to when you last ate

With or without diabetes, in general, hyperglycemia is regarded as too high when it is 160 mg/dL or greater than your personal blood glucose target. Ask a healthcare provider any questions you have about your personal blood glucose target.

If your blood glucose is 240 mg/dL or greater and you take insulin, check your urine for ketones. If ketones are present, follow your "sick day" rules (as established with your healthcare provider) or contact a healthcare provider if you are unsure what to do.

When Should You See a Healthcare Provider for Hyperglycemia?

Because prolonged hyperglycemia is a serious medical condition and can be very dangerous, it’s important to know when to see a healthcare provider for treatment. 

Seek medical treatment immediately if you are experiencing signs or symptoms of ketoacidosis, such as:

Seek emergency care if you are experiencing symptoms of hyperglycemic hyperosmolar syndrome, including:

  • Dehydration
  • Confusion
  • Decreased alertness
  • Passing out or decreased consciousness

Testing for Elevated Glucose Levels 

If you are at risk for hyperglycemia, it’s important to have your blood sugar levels checked regularly. Anyone who has symptoms of hyperglycemia should be tested to help prevent complications from occurring. 

Common tests for hyperglycemia include:

  • A1C test: This test reflects your blood glucose levels over the past three months.
  • Fasting plasma glucose test: This test measures your blood glucose levels after fasting for at least eight hours or overnight.
  • Random plasma glucose test: This test measures your blood glucose levels without regard to when you last ate.
  • Oral glucose tolerance test (OGTT): This test measures your blood glucose after you have fasted for at least eight hours. Then you will drink a liquid containing glucose and subsequently have your blood drawn to measure your blood glucose every hour for one, two, or three hours, depending on the test.

It’s recommended that people without diabetes who have normal glucose results be tested every three years. People who do not have diabetes and are pregnant should be tested for gestational diabetes between 24 and 28 weeks of each pregnancy.

If you have diabetes, follow your healthcare provider’s recommendations on how often you should have your blood glucose levels tested.

Hyperglycemia Treatment

Hyperglycemia treatment will help blood sugar levels return to a normal range. Talk with a healthcare provider to learn how to best treat your hyperglycemia. They may suggest the following:

  • Take your medication as prescribed: If you are taking your medicine as instructed and are still having frequent high blood sugar levels, talk with your healthcare provider about changing the dose or the time you take the medication.
  • Be physically active: Participating in regular exercise can help improve insulin sensitivity and bring blood glucose levels down. However, if you have ketones in your urine, do not exercise, as this may make your blood sugar levels go higher.
  • Follow a healthy diet: Talk with a healthcare provider or registered dietitian (RD) or registered dietitian nutritionist (RDN) if you have questions about what dietary pattern is best for you.
  • Check your blood glucose levels as directed: You can also check it more often than directed if you are concerned about your blood sugar levels.

In addition to conventional treatment, there are several alternative treatments, such as:

Complications From Untreated Hyperglycemia

In addition to DKA and HHS, untreated hyperglycemia can lead to other medical conditions, such as:

How to Check for Hyperglycemia at Home

Knowing how to test your blood glucose levels at home is a big component of blood glucose self-management.

The first step is to purchase or get a prescription for a blood glucose monitor, also called a blood glucose meter or glucometer, and test strips. This device measures the amount of glucose in a small amount of blood, usually from your fingertip.

Your healthcare provider or a certified diabetes care and education specialist (CDCES) can teach you and/or a caregiver how to use it. They will instruct you on when and how often you need to test your blood glucose levels at home, such as when you first wake up and before eating, two hours after a meal, or at bedtime. 

You might qualify for a continuous glucose monitor (CGM), depending on your diagnosis. This small wearable device automatically checks your blood glucose levels throughout the day and night. Blood glucose levels are wirelessly sent to a separate receiver or smart device where you can read the results.

Balancing Self-Management and Conventional Treatments With a Provider

Managing your blood glucose levels is often a joint effort between you and your healthcare team. While you are in charge of the day-to-day management of your glucose levels, your healthcare provider can recommend an individualized treatment plan to help keep your blood glucose levels in a normal range. 

If you have concerns or questions about your treatment plan, be sure to bring it up with your healthcare provider. They have your best interests in mind and want you to feel happy and confident in your treatment and management plan.

Daily Hyperglycemia Management 

If you are at risk for hyperglycemia or experience hyperglycemia often, you should actively manage your blood sugar levels on a daily basis. Follow the treatment plan recommended by your healthcare provider, which may include:


Hyperglycemia is high blood glucose levels. Symptoms include increased thirst and urination, blurred vision, and tingling in the hands and feet. Hyperglycemia often occurs in people with diabetes but can also occur in people without diabetes.

Causes of hyperglycemia include insulin resistance, lack of insulin production, certain medications, stress, and some medical conditions.

A healthcare provider can perform tests for hyperglycemia, such as an A1C, fasting and random plasma glucose, and oral glucose tolerance test. Seek emergency medical attention if you experience any symptoms of diabetic ketoacidosis or hyperglycemic hyperosmolar syndrome.

Treatment for hyperglycemia may include insulin or another medication, following a healthful diet, exercising regularly, and monitoring blood glucose levels at home.

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Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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By Brittany Poulson, MDA, RDN, CD, CDCES
Brittany Poulson, MDA, RDN, CDCES, is a registered dietitian and certified diabetes care and education specialist.