Having high blood sugar means you have elevated levels of glucose in your blood and could indicate prediabetes or diabetes. Glucose is a carbohydrate (simple sugar) used as primary fuel for vital functions like brain and muscle activity, among others.

High blood sugar (hyperglycemia) occurs when your body doesn’t produce enough insulin, cannot absorb it properly, or develops a resistance to it entirely. Insulin is a hormone your pancreas produces to keep blood glucose in check.

People with or without diabetes may experience hyperglycemia. For example, your blood sugar levels can spike when you’re ill or under stress. This occurs when your body’s hormones to fight illness raise your blood sugar.

If your blood sugar levels are consistently high and left untreated, it may mean you have prediabetes or diabetes and these may lead to serious complications. These complications can involve problems with your vision, nerves, and cardiovascular system.

Have you ever felt like no matter how much water or juice you drink, it just isn’t enough? Does it seem like you spend more time running to the restroom than not? Are you frequently tired and hungry? You may have high blood sugar if you answered yes to any of these questions.

You generally won’t experience any symptoms of hyperglycemia until your blood sugar levels are significantly elevated. These symptoms can develop over time, so you may not realize something is wrong. In other words, high blood sugar may not feel like anything in particular until it becomes chronic.

If you have chronic or unmanaged high blood sugar, it may feel like:

  • needing to urinate more frequently
  • being thirsty most of the time
  • having blurred vision at times or persistently
  • experiencing constant headaches
  • being fatigued without apparent reason
  • vomiting without apparent reason
  • having nausea
  • having dry mouth, even after drinking water
  • experiencing shortness of breath
  • having frequent abdominal pain

If you experience a combination of these symptoms, it is highly advised that you see a healthcare professional as soon as possible to prevent complications.

If you haven’t received a diabetes diagnosis, your target blood glucose levels are 100 mg/dL or below while fasting. Anything over that indicates high blood sugar and could signal prediabetes or diabetes. A healthcare professional may want to do further testing if your blood sugar levels are high.

Glucose levels equal or higher than 200 mg/dL when not fasting indicate diabetes.

Your personal blood sugar targets may be different based on many factors, including:

  • your age
  • type of diabetes
  • other health conditions
  • medications you take
  • your risk factors for low blood sugars

Depending on your results, a doctor may recommend a routine blood sugar check at home with a fingerstick meter or a continuous glucose monitor (CGM) device.

If you have diabetes and actively managing it, the American Diabetes Association recommends a target blood glucose range of 80 to 130 milligrams per deciliter (mg/dL). That includes:

  • 80 to 130 mg/dL before a meal
  • 180 mg/dL or less 2 hours after starting to eat

Blood sugar levels of 240 mg/dL and higher can be dangerous, possibly leading to high ketones and a condition known as diabetic ketoacidosis, which is a medical emergency requiring immediate care.

The diabetes care team can best guide you on managing your blood sugar targets and what works best for you.

Other questions to discuss with a doctor

At your next appointment, you can discuss specific health and lifestyle factors that affect your blood sugars. These may play a role in developing hyperglycemia and how a doctor can help manage your diabetes and overall health.

  • Have your eating habits changed?
  • Are you drinking enough water each day?
  • Are you experiencing more stress at work or in your life?
  • Have your sleeping patterns changed?
  • Any accidents, or were you in the hospital for surgery?

Hyperglycemia may affect you regardless of whether you have diabetes. You may be at risk of hyperglycemia if you:

  • lead a sedentary or inactive lifestyle
  • have a chronic (long-term) or severe illness
  • are under emotional distress
  • use certain medications, such as steroids
  • have had a recent surgery

If you have diabetes, your blood sugar levels may spike if you don’t:

  • follow your diabetes eating plan
  • use your insulin as instructed
  • take your medications as indicated

A doctor may recommend a low impact exercise program as your first line of defense. If you’re already following a fitness plan, they may recommend increasing your overall activity level.

A doctor may also suggest you reduce glucose-rich food intake.

It’s important to maintain a balanced diet and follow portion control. If you aren’t sure where to begin, a doctor can refer you to a dietitian or nutritionist who can help you plan your diet.

If these changes don’t help lower your high blood sugar, a doctor may prescribe medication. If you have diabetes, they may prescribe oral (taken by mouth) medications or change the amount or type of insulin they have prescribed earlier.

High blood sugar can occur in people with or without diabetes. You may experience excessive thirst and frequent urination as early symptoms. If not managed over time, hyperglycemia can lead to more serious complications that may affect your eyes, nerves, heart, and other organs.

A healthcare team may recommend that you buy a blood meter to use at home. Being aware of your levels can empower you to take charge of your condition and live a healthy lifestyle.

A care team will provide clear steps to follow to lower your blood sugar levels. It’s important that you take their recommendations to heart and make any necessary lifestyle changes to improve your health.

Learn more about prediabetes and type 2 diabetes

No matter where you are on your care journey, you can find more information and support to help you live with diabetes.