Type 2 Diabetes

Type 2 Diabetes

What Is Hyperglycemia? How to Prevent, Detect, and Treat High Blood Sugar

Something as simple as a big meal or an intense workout can cause your blood sugar to spike, but problems occur when your body can’t bring your levels back down because of insulin resistance or a lack of insulin.

Kristeen Cherney, PhD
By Medically Reviewed by 
Reviewed:
Medically Reviewed
Sugar cube hypoglycemia blood sugar spike
People with type 2 diabetes have insufficient insulin and insulin resistance, leading to hyperglycemia, or high blood sugar.Adobe Stock
If you have to pee frequently, are constantly fatigued despite getting enough rest, or have suddenly lost weight, you may have hyperglycemia, or high blood sugar.

What exactly causes hyperglycemia, when is it dangerous, and how can uncontrolled blood sugar affect your future health?

How Is Hyperglycemia Diagnosed, Exactly?

If you have insulin resistance, prediabetes, type 1 diabetes, gestational diabetes, or type 2 diabetes, your body either doesn’t make enough of the hormone insulin, or it does make enough insulin but isn’t able to use it correctly. Insulin is critical for regulating blood sugar levels because it ferries blood sugar, or glucose, to our cells and muscles for immediate energy or to store for later use.

Typically, your doctor will diagnose you with insulin resistance, prediabetes, or diabetes after seeing that your blood sugar levels are abnormal. Often, the test they’ll use is the hemoglobin A1C, or A1C test for short, says Gregory Dodell, MD, an assistant clinical professor of medicine, endocrinology, diabetes, and bone disease at the Icahn School of Medicine at Mount Sinai in New York City.

A1C is a two- to three-month average of your blood sugar levels, says Dr. Dodell, explaining that the test measures the percentage of sugar that’s attached to your red blood cells.

Here’s what your A1C result means:

  • Under 5.7 percent: normal
  • 5.7 to 6.4 percent: prediabetes
  • Over 6.5 percent: diabetes

If your A1C is over 6.5 percent on two or more separate occasions, you likely have diabetes.

Dodell says your doctor may also test your blood sugar levels through a fasting glucose test. Here’s what those results mean:

  • Under 100 milligrams per deciliter (mg/dL): normal
  • 100 to 125 mg/dL: prediabetes (or impaired fasting glucose)
  • Over 125 mg/dL: diabetes

As with the A1C test, if your fasting glucose level is over 125 mg/dL on two separate occasions, you likely have diabetes.

Glucose is your body’s primary energy source, which you get from many of the foods you eat, including fruit, bread, veggies, and quinoa.

While many people tend to associate high blood sugar most closely with type 2 diabetes, other conditions are linked with hyperglycemia, too.

Here’s a primer on hyperglycemia.

What Are Some of the Common Signs and Symptoms of High Blood Sugar?

If you regularly monitor your blood sugar, you’ll see elevated readings from blood or urine samples. But physical symptoms of the condition may show up as well.

In addition to frequent urination, fatigue, and sudden weight loss, symptoms of hyperglycemia may include:

  • Intense hunger
  • Irritability
  • Wounds or sores that won’t heal
  • Increased thirst
  • Frequent infections (including those in the gums, on the skin, or in the vagina)
  • Ketones in the urine (ketones are by-products of fat or muscle that appear when insulin is insufficient)
  • Blurry vision
  • Frequent headaches

What Are the Health Consequences of High Blood Sugar?

These symptoms can worsen if you don’t treat high blood sugar. Too-high blood sugar levels can even lead to a life-threatening condition called diabetic ketoacidosis, also called diabetic coma.

During ketoacidosis, your body breaks down large amounts of fat at once, and as a result, ketones are excreted and sent to your urine. But when there are too many ketones, your body can’t keep up with this excretion process, causing ketones to accumulate in your bloodstream. Signs of ketoacidosis from high blood sugar can include dry mouth, fruity-smelling breath, nausea, and shortness of breath. You may even have anxiety and vomiting.

Another possible complication of high blood sugar is called hyperglycemic hyperosmolar syndrome. With this condition, your blood glucose readings may be 600 mg/dL or higher. It occurs when you do have enough insulin, but your body’s not using it right. The glucose isn’t used up by your body, and instead transfers to your urine, causing severe dehydration. Hyperglycemic hyperosmolar syndrome is considered an emergency and can lead to potentially life-threatening dehydration or even coma.

With consistently high blood sugar, you’re also at risk for several health complications down the line — from stroke and heart disease, to vision problems (retinopathy) and nerve damage (neuropathy).

What Are the Different Causes of High Blood Sugar?

High blood sugar can be seen in various forms of diabetes, including type 1, type 2, and gestational.

People with type 1 diabetes experience high blood sugar because their bodies don’t produce insulin. On the other hand, if you have type 2 diabetes or gestational diabetes, you might have adequate insulin, but your cells and muscles can’t absorb it properly due to insulin resistance.

But you can also develop hyperglycemia if you don’t have diabetes. In these cases, episodes of hyperglycemia are usually temporary. Your blood sugar may rise after you eat a large meal or as a result of a high-endurance workout. Emotional stresses and illnesses can also cause these fluctuations.

Are You at Risk for High Blood Sugar? How to Know

You may be at risk for high blood sugar if you have diabetes and you:

  • Eat too many processed or fast foods
  • Don’t exercise regularly
  • Eat large meals, or engage in binge eating
  • Are under a lot of stress on a regular basis, either from work, dating, or another factor
  • Have recurring illnesses
People with type 1 diabetes may develop high blood sugar if they haven’t taken enough insulin or if they are not consuming an optimal amount of carbs relative to their medication.

Genetics can also play a role, especially if you have a family history of diabetes, says Dodell. He explains that certain health conditions can raise your risk of high blood sugar, including damage to the pancreas — such as pancreatic cancer or pancreatitis — infection, pain, and polycystic ovary syndrome, a hormone disorder that can cause infertility.

The Best Foods to Eat to Help Avoid or Lower Your High Blood Sugar

While there’s no such thing as a hyperglycemia diet per se, your eating choices still play an important role in regulating your blood sugar levels.

First, know you can’t just cut all carbs or avoid foods with sugar to prevent blood sugar spikes. After all, healthy foods, such as fruits and veggies, also contain carbs and sugar. The value of carbs differs according to their complexity, and sugar in food is different from blood sugar.

That said, you should try to avoid these foods to help prevent blood sugar spikes:

  • White bread, pasta, and rice
  • Packaged and processed snacks, such as chips, pretzels, cookies, and candy
  • Soda or juice
  • Fast food
  • Foods high in saturated fat, such as hot dogs, bacon, and sausage
  • Foods high in trans fats, like margarine and certain packaged baked goods
  • Foods that can raise your cholesterol, like liver, red meat, and full-fat dairy

Tracking your carb intake, especially if you have diabetes, is also critical for avoiding blood sugar spikes.

To help keep your blood sugar levels steady, try eating fish twice a week, as well as concentrating on plant-based fats and fiber-rich foods regularly.

You may also consider talking to your doctor or dietitian about the following diets:

Cutting down on overall portion sizes can also help keep blood sugar levels steady.

If you do have a larger meal than normal and take insulin, you may need to up your insulin dose to compensate.

One study found that nutritional excess in pregnant women increased the risk of hyperglycemia and fatty liver disease in both mother and fetus.

Consider using the plate method, which can help you control your portions, or working with a dietitian to come up with a custom meal plan.

How Lifestyle Changes Can Also Help You Avoid Hyperglycemia

Exercise is one of the best ways to get rid of high blood sugar. But if you have ketoacidosis, you should not exercise but rather go to the emergency room. You’ll want to check your urine for ketones to be safe, especially if your glucose reading is 250 mg/dL or higher.

When you exercise, your body uses glucose as its primary energy source. This, in effect, will help bring down your blood sugar levels. Working out regularly will lower your A1C.

Work with your healthcare provider or hire a personal trainer to figure out which exercises are best for you, based on your goals and your overall fitness level. Some exercises can affect your blood sugar more than others. For instance, high-intensity workouts, such as running or spinning, burn more glucose, while longer bouts of low-intensity exercises, like walking, burn more fat. Either option can help increase insulin sensitivity. You should also measure your sugar before and after each workout.

Diabetes Medication That Can Help You Control Your Blood Sugar

If you’ve been diagnosed with diabetes, your doctor will likely discuss medication options to help bring your blood sugar down. If you have prediabetes, on the other hand, you’ll probably rely on diet and lifestyle changes to help stabilize your numbers, though in some cases, you may need medication, Dodell says.

Diabetic ketoacidosis is treated with emergency insulin and fluids administered intravenously. But the goal with blood sugar control is to prevent this type of medical emergency from happening in the first place. If your blood glucose readings are consistently higher than usual, you may not be getting enough insulin. Talk to your doctor about adjusting your dosage. You should also tell them about any other prescription or over-the-counter medications you take, as these could affect your blood sugar, too. Corticosteroids for inflammation are just one example.

If you’re receiving emergency medical treatment for high blood sugar complications, your doctor may administer fluids and electrolytes.

How Technology Can Help You Keep Your Blood Sugar Levels Balanced

If you have diabetes, you should wear a medical ID bracelet in case your blood sugar spikes to a dangerous range. You can even attach a USB drive to the bracelet with key personal information that a medical professional might need in case of an emergency.

Tracking high blood sugar can be done easily with your fingertips, too. Check out some of the apps you may download onto your smartphone — among the top-rated apps on iOS and Android are Blood Glucose Tracker, Glucose Buddy Diabetes Tracker, and mySugr.

The Takeaway on Preventing and Treating Hyperglycemia

Avoiding and treating hyperglycemia is a three-tiered process — this includes taking your treatments as directed, exercising, and eating a healthy diet with smaller portions.

The effort is worth it. Getting your blood sugar under control can ultimately help increase your quality of life now and help ward off complications in the future.

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