Prediabetes Explained: Warning Signs, Risk Factors, and What You Can Do
Written by HeartView Health Editorial Team
Technology reviewed by Dishant Chanchad, Chief Technology Officer
Published August 11, 2026Updated September 3, 202611 min read
Prediabetes affects an estimated one in three adults, and the vast majority don’t know they have it.
Prediabetes is a common health condition in which blood glucose levels are higher than normal but not yet high enough to meet the diagnostic criteria for type 2 diabetes. It is often described as a warning sign because it can indicate that the body is beginning to have difficulty regulating blood sugar effectively.
One of the biggest challenges with prediabetes is that many people do not notice anything unusual. Blood sugar can gradually increase without causing obvious symptoms, which means routine screening can be important, particularly for people who have risk factors for diabetes.
The good news is that identifying prediabetes early creates an opportunity to make meaningful changes. Improvements in physical activity, eating habits, sleep, weight management, and other lifestyle factors can reduce the likelihood of progressing to type 2 diabetes.
What Does Prediabetes Actually Mean?
Prediabetes means that your blood glucose is above the normal range but below the level used to diagnose diabetes.
After you eat, carbohydrates are broken down into glucose, which enters your bloodstream. Your pancreas produces insulin, a hormone that helps glucose move from the blood into cells where it can be used for energy.
With insulin resistance, cells become less responsive to insulin. The pancreas may compensate by producing more insulin to keep blood glucose within a reasonable range. Over time, however, the body's ability to maintain normal glucose levels may become less effective.
Prediabetes can therefore be an early sign of metabolic changes that increase the future risk of type 2 diabetes and cardiovascular disease.
Having prediabetes does not mean that you will definitely develop diabetes. It means your current blood sugar levels and risk factors deserve attention.
The Diagnostic Numbers
Prediabetes can generally be identified using one of several blood glucose tests.
| Test | Normal | Prediabetes | Diabetes |
|---|---|---|---|
| Fasting blood glucose | Below 100 mg/dL | 100–125 mg/dL | 126 mg/dL or higher |
| HbA1c | Below 5.7% | 5.7–6.4% | 6.5% or higher |
| Oral glucose tolerance test, 2-hour | Below 140 mg/dL | 140–199 mg/dL | 200 mg/dL or higher |
A healthcare professional may recommend repeating testing or using another test to confirm an abnormal result, depending on the circumstances.
What Is Fasting Blood Glucose?
A fasting blood glucose test measures your blood sugar after you have not eaten for a specified period, usually overnight.
A fasting glucose result between 100 and 125 mg/dL falls within the commonly used prediabetes range.
The test is relatively simple, but temporary factors such as illness, stress, sleep disruption, and certain medications can affect blood glucose.
What Is HbA1c?
HbA1c, also called glycated hemoglobin, provides an estimate of your average blood glucose levels over approximately the previous two to three months.
Unlike a single glucose measurement, HbA1c is less affected by short-term fluctuations from one meal or one stressful day. It is therefore commonly used to assess longer-term blood sugar patterns.
An HbA1c between 5.7% and 6.4% is generally considered within the prediabetes range.
What Is an Oral Glucose Tolerance Test?
An oral glucose tolerance test measures how your body responds to glucose.
After fasting, a blood sample is taken, followed by consumption of a glucose-containing drink. Blood glucose is measured again after a specified period, commonly two hours.
A two-hour glucose result between 140 and 199 mg/dL is within the commonly used prediabetes range.
The appropriate test depends on your individual circumstances and your healthcare provider's recommendation.
Who Is at Higher Risk of Prediabetes?
Prediabetes can affect people with different body types and lifestyles, but certain factors increase risk.
Excess Body Weight
Being overweight, particularly when excess fat is concentrated around the abdomen, is associated with increased insulin resistance.
Even modest weight reduction can improve insulin sensitivity in people who are at increased metabolic risk.
Physical Inactivity
Regular physical activity helps muscles use glucose for energy and can improve insulin sensitivity.
A sedentary lifestyle can make it harder for the body to regulate blood glucose effectively.
Age
The risk of prediabetes and type 2 diabetes generally increases with age, although diabetes can occur in younger adults as well.
Family History
Having a close family member with type 2 diabetes can increase your risk. Genetics interact with lifestyle and environmental factors, so family history is an important part of an overall risk assessment.
History of Gestational Diabetes
People who have experienced diabetes during pregnancy have an increased future risk of developing type 2 diabetes.
Appropriate follow-up testing can therefore be especially important after gestational diabetes.
Polycystic Ovary Syndrome
Polycystic ovary syndrome, or PCOS, is associated with insulin resistance in many people and can increase the risk of prediabetes and type 2 diabetes.
Blood Pressure and Cholesterol
High blood pressure and abnormal cholesterol or triglyceride levels can occur alongside insulin resistance and other metabolic risk factors.
Having several risk factors together may increase overall cardiovascular and diabetes risk.
Why Prediabetes Often Goes Unnoticed
Prediabetes commonly produces no obvious symptoms.
This is one reason routine screening can be valuable. A person can have blood glucose in the prediabetes range while feeling completely healthy.
Some people may notice symptoms as blood sugar rises, such as increased thirst, more frequent urination, fatigue, or changes in energy levels. However, these symptoms are not specific to prediabetes and can have many other causes.
Darkened, thickened areas of skin, particularly around the neck or armpits, may occur in some people with insulin resistance. This condition is called acanthosis nigricans.
The absence of symptoms does not mean that blood sugar is necessarily normal. Testing is the most reliable way to determine your glucose status.
Can Prediabetes Be Reversed?
Prediabetes can often improve, particularly when lifestyle changes are introduced early.
Research from the Diabetes Prevention Program demonstrated that structured lifestyle intervention significantly reduced the risk of progression to type 2 diabetes among people at high risk. The program emphasized modest weight loss, increased physical activity, and sustainable dietary changes.
The goal is not necessarily to make extreme changes. Consistent, realistic improvements can have meaningful effects on metabolic health.
The Importance of Modest Weight Loss
For people who are overweight, losing a modest amount of body weight can improve insulin sensitivity and reduce diabetes risk.
Research from the Diabetes Prevention Program found that a weight reduction of approximately 5–7% of initial body weight, combined with increased physical activity, was associated with a substantial reduction in the risk of developing type 2 diabetes.
For someone weighing 80 kg, 5–7% would be approximately 4–5.6 kg.
The appropriate weight goal varies from person to person. Weight should therefore be considered as one part of a broader health plan rather than as the only measure of success.
Physical Activity and Prediabetes
Regular movement is one of the most effective lifestyle strategies for improving metabolic health.
A commonly recommended target for adults is around 150 minutes of moderate-intensity physical activity per week, such as brisk walking, cycling, swimming, or similar activities.
You do not have to complete all 150 minutes at once. Breaking activity into shorter sessions throughout the week can make it easier to maintain.
Strength training can also support metabolic health by helping maintain or build muscle, which plays an important role in glucose use.
If you have been inactive for a long period, start gradually and choose activities that are appropriate for your current fitness level.
Why Walking After Meals May Help
Physical activity after eating can help muscles use circulating glucose.
Even a short walk after a meal can be a practical way to add movement to your day. It may also be easier to maintain than trying to schedule one long exercise session.
The important goal is consistency. Regular movement throughout the day can be more sustainable than relying on occasional intense workouts.
Food Choices That Support Healthy Blood Sugar
There is no single diet that works for everyone with prediabetes.
However, several general dietary principles can support better blood glucose management.
Choose More Fiber-Rich Foods
Fiber is found in vegetables, fruits, beans, lentils, whole grains, nuts, and seeds.
Fiber can slow digestion and glucose absorption while helping you feel full after meals.
Prioritize Protein
Including a source of protein with meals can improve satiety and help create a more balanced meal.
Examples include eggs, fish, poultry, beans, lentils, yogurt, tofu, nuts, and other protein-rich foods that fit your dietary preferences.
Limit Refined Carbohydrates
Foods made with highly refined grains and large amounts of added sugar can produce rapid increases in blood glucose.
Reducing sugary drinks, sweets, and highly processed carbohydrate-heavy foods can be a useful step.
Focus on Overall Meal Quality
Rather than eliminating an entire food group, focus on creating balanced meals that include vegetables, protein, high-fiber carbohydrates, and healthy fats in appropriate portions.
Small changes that you can maintain for months and years are generally more useful than short-term restrictive diets.
The Role of Sleep
Sleep is often overlooked when discussing blood sugar.
Poor sleep and insufficient sleep can affect hormones involved in appetite, metabolism, and insulin sensitivity.
People who regularly have difficulty sleeping or who experience symptoms such as loud snoring, breathing interruptions during sleep, or excessive daytime sleepiness should discuss these concerns with a healthcare professional.
Improving sleep habits can be an important part of an overall strategy for metabolic health.
Stress and Blood Sugar
Chronic stress can influence blood glucose through hormonal changes.
When the body experiences stress, hormones such as cortisol and adrenaline help prepare it to respond to a perceived challenge. These hormones can temporarily increase blood glucose.
Stress can also indirectly affect blood sugar by making it more difficult to maintain healthy eating patterns, regular exercise, or consistent sleep.
Finding practical ways to manage stress—such as walking, relaxation exercises, hobbies, social connection, or structured routines—can support overall health.
Practical Steps If You Have Prediabetes
If you have been told that you have prediabetes, consider discussing the following steps with your healthcare provider:
1. Understand Your Numbers
Ask which test was used, what your result was, and how it compares with the normal and diabetes ranges.
Understanding your baseline makes future results easier to interpret.
2. Create an Activity Routine
Aim for regular movement throughout the week. Start with manageable activities and gradually increase duration or intensity.
3. Review Your Eating Habits
Look for realistic opportunities to increase vegetables, fiber, and protein while reducing excessive added sugars and highly processed foods.
4. Track Progress
Depending on your healthcare provider's recommendations, you may track weight, physical activity, blood glucose, or other health measurements.
The goal is to identify trends rather than become overly focused on one day's result.
5. Follow Up With Your Healthcare Provider
Prediabetes should not simply be identified and forgotten.
Follow-up testing can help determine whether blood glucose is improving, remaining stable, or moving toward the diabetes range.
Prediabetes and Heart Health
Prediabetes is not only about future diabetes risk.
Elevated blood glucose and insulin resistance can occur alongside other cardiovascular risk factors, including high blood pressure, abnormal cholesterol, excess weight, and physical inactivity.
For this reason, improving metabolic health can also support broader cardiovascular health.
Your healthcare provider may consider blood pressure, cholesterol, weight, family history, smoking status, physical activity, and other factors when assessing your overall risk.
Can Medication Be Used for Prediabetes?
Lifestyle changes are an important part of preventing or delaying type 2 diabetes.
In some people at particularly high risk, a healthcare professional may also consider medication such as metformin. Whether medication is appropriate depends on individual factors, medical history, laboratory results, age, weight, and other considerations.
Do not start, stop, or change diabetes medication without professional guidance.
Prediabetes is a warning sign, but it does not have to become a diagnosis of type 2 diabetes.
Because prediabetes often causes few or no symptoms, testing is one of the most important ways to identify it. Understanding your blood glucose numbers, recognizing your personal risk factors, and following up with a healthcare professional can give you an opportunity to act early.
For people at increased risk, sustainable lifestyle changes can make a meaningful difference. Regular physical activity, nutritious food choices, adequate sleep, stress management, and appropriate weight management can all support better metabolic health.
The goal is not perfection. It is consistent progress that can be maintained over time.
Medical Disclaimer: This article is intended for general informational and educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Blood glucose targets, screening recommendations, and treatment decisions can vary based on individual circumstances. Always consult a qualified healthcare professional regarding blood sugar testing, prediabetes, diabetes risk, and treatment options.
Sources & References
- Insulin Resistance & Prediabetes. National Institute of Diabetes and Digestive and Kidney Diseases (NIH).
- Hemoglobin A1C (HbA1c) Test. MedlinePlus, U.S. National Library of Medicine.
This article is for general information only and is not a substitute for professional medical advice, diagnosis or treatment. Read our Medical Disclaimer.
Frequently Asked Questions
No. Prediabetes means blood glucose is higher than normal but below the diagnostic range for diabetes. It indicates increased metabolic risk but does not automatically mean that a person has diabetes
Common Questions About Diabetes
What is prediabetes?
Prediabetes means your blood sugar levels are higher than normal but not yet high enough to meet the criteria for type 2 diabetes. It often reflects early insulin resistance and can increase the risk of developing type 2 diabetes over time.
What blood sugar level is considered prediabetes?
Prediabetes can be identified through different blood tests. A fasting blood glucose level of 100–125 mg/dL, an HbA1c of 5.7%–6.4%, or a 2-hour oral glucose tolerance test result of 140–199 mg/dL falls within the prediabetes range.
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