Understanding prediabetes

What prediabetes means, how it's diagnosed, why it matters for your heart and future health, and why it's a chance to make a real difference.

5 min read · last reviewed October 3, 2026

Being told you have prediabetes can be confusing. You don't have diabetes, but something isn't quite right. Should you worry? What should you do?

Think of prediabetes as an early heads-up. It's your body letting you know that blood sugar is starting to creep up, while there's still plenty of time to do something about it. That's actually good news. Many people only find out about blood sugar problems once they already have diabetes.

What is prediabetes?

When you eat, your body turns carbohydrates into a sugar called glucose, which travels in your blood to give your cells energy. A hormone called insulin, made by your pancreas, works like a key that lets glucose into your cells.

In prediabetes, your cells start to respond less well to insulin. This is called insulin resistance. Your pancreas works harder to make extra insulin, and for a while that's enough. But blood sugar starts to rise above the normal range. In prediabetes, it isn't yet high enough to be called diabetes.

How common is it?

Very common. Millions of adults in Canada and the U.S. have prediabetes, and most don't know it, because it usually doesn't cause any symptoms.

How is it diagnosed?

Prediabetes is found with the same blood tests used to check for diabetes. Diabetes Canada uses these ranges for prediabetes:

• A1C (average blood sugar over 2 to 3 months): 6.0% to 6.4%
• Fasting blood sugar (after at least 8 hours without food): 6.1 to 6.9 mmol/L (about 110 to 125 mg/dL)
• 2-hour glucose drink test: 7.8 to 11.0 mmol/L (about 140 to 199 mg/dL)

The American Diabetes Association uses slightly lower starting points: an A1C of 5.7% to 6.4%, or a fasting blood sugar of 5.6 to 6.9 mmol/L (100 to 125 mg/dL). That's why you might see different numbers in different places. Your team will explain what your results mean for you.

Something you can do today: Ask for your actual test numbers and write them down. They're a useful starting point to track your progress.

Who gets prediabetes?

Many things raise the chance of prediabetes and type 2 diabetes. Some you can't change:

• Age, especially over 40
• A parent, brother or sister with type 2 diabetes
• Ethnic background, including South Asian, Asian, African, Caribbean, Hispanic and Indigenous heritage
• Having had diabetes in pregnancy (gestational diabetes) or a baby weighing more than 4 kg (9 lb)
• Polycystic ovary syndrome (PCOS)

Others can be influenced over time:

• carrying extra weight, especially around the belly
• not being very active
• high blood pressure or cholesterol
• smoking
• poor sleep, stress, and some medicines such as steroids

Prediabetes is not your fault. Genes, family history and life circumstances play a big part.

Does prediabetes cause symptoms?

Usually not. Most people feel completely well. That's why testing matters. If your blood sugar rises into the diabetes range, you might notice thirst, peeing more, tiredness or blurry vision. If that happens, see your doctor.

Why does it matter?

Prediabetes raises your chance of:

• developing type 2 diabetes
• heart disease and stroke, even before diabetes develops

But it's important to know that prediabetes doesn't mean you will get diabetes. Many people with prediabetes never develop diabetes, and some go back to normal blood sugar levels. Your choices really can make a difference.

The hopeful part

Research shows that healthy changes work. In the Diabetes Prevention Program, a large U.S. study, people with prediabetes who made lifestyle changes, aiming to lose about 7% of their body weight and be active for 150 minutes a week, cut their chance of developing type 2 diabetes by 58% over about 3 years. Read Turning prediabetes around to learn how.

Something you can do this week: Take a 10-minute walk after one meal each day. It's a simple start that helps your blood sugar.

Keeping an eye on things

Because prediabetes can slowly change, your team will usually re-check your blood sugar regularly, often once a year. They may also check your blood pressure and cholesterol, since these affect your heart health too.

Prediabetes runs in families, so let your family know. Diabetes Canada suggests that most adults over 40, and younger adults with risk factors, get checked regularly. In Canada, you can use the free CANRISK questionnaire to check your risk.

Questions to ask your care team

• What were my test results, and what do they mean?
• How likely am I to develop type 2 diabetes?
• When should my blood sugar be checked again?
• Are my blood pressure and cholesterol okay?
• Is there a diabetes prevention program near me or online?
• Should my family members be tested?

This article is general information, not medical advice. Talk with your health care team about your own situation. In an emergency, call 9-1-1 or your local emergency number.

In an emergency, call 9-1-1 or your local emergency number.

General information, not medical advice. It does not replace your own care team. If you think you or someone else is having a medical emergency, call 9-1-1 or your local emergency number. If you are in crisis or thinking about suicide, call or text 9-8-8 (Canada and the US).

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