What is blood sugar?

Blood sugar, or glucose, is the main sugar found in your blood. It comes from the food you eat and is your body’s main source of energy. Your blood carries glucose to all of your body’s cells to use for energy. Diabetes is a disease in which your blood sugar levels are too high. Over time, having too much glucose in your blood can cause serious problems.

What is the normal range for blood sugar?

Normal levels for A1C tests are below 5.7 percent, and normal levels for a fasting blood glucose test are 99 mg/dL or below.

What are the symptoms of high blood sugar?

There may not always be signs of high blood sugar. This is why you should talk to your doctor about your risk for type 2 diabetes. If someone’s blood sugar level is very high, they may have blurry vision, feel thirsty, feel tired, and pee often. You cannot rely on symptoms to know if you have type 2 diabetes. Talk to your doctor.

What are the effects of high blood sugar?

If you have diabetes, your body either doesn’t make enough insulin or can’t use the insulin it makes as well as it should. When there isn’t enough insulin, too much blood sugar stays in your bloodstream. Over time this can cause serious health problems, such as heart disease, vision loss, and kidney disease.

How can you lower your blood sugar?

You can lower your blood sugar (and risk for prediabetes and type 2 diabetes) by making healthy lifestyle changes. These include losing weight, eating healthier, and getting regular physical activity. The CDC-led National Diabetes Prevention Program can help you make healthy changes that last.

For information on how to track blood sugar, visit the CDC’s website.


With early diagnosis, prediabetes can often be reversed. By joining a National DPP lifestyle change program, you’ll learn how to make simple changes to help reverse prediabetes and prevent type 2 diabetes. Find an online or in-person program below.