Expert Rita Rastogi Kalyani, MD, MHS, is an assistant professor at Johns Hopkins School of Medicine.
A: Prediabetes means your blood sugar (glucose) level is above normal, but not high enough to be considered diabetes. The higher level means your body is starting to have trouble using the hormone insulin, which normally moves glucose from the blood into your body's cells. Without insulin working properly, glucose begins to build up in your bloodstream.
Prediabetes is a warning, signaling that you could get diabetes if you don't change your lifestyle. Also, higher-than-normal blood sugar over time puts you at risk for complications like heart disease and nerve damage (neuropathy).
Prediabetes often doesn't have any symptoms, so you may not know you have it. Your doctor can measure your blood sugar during a routine blood screening test. To decide whether to screen, your doctor will look at risk factors like:
- Your age (if you're 45 or older)
- Ethnic background
- Are you overweight?
- Do you have a family history of diabetes?
- Do you have high blood pressure or high cholesterol?
- Are you a woman who had gestational diabetes during a pregnancy?
Your doctor might order one or more of three blood tests to measure your blood sugar. A fasting blood glucose test checks your blood sugar level after you haven't eaten anything for at least 8 hours. The hemoglobin A1c test shows your average blood sugar levels over the past 3 months. And an oral glucose tolerance test checks your blood sugar 2 hours after you have a carbohydrate-containing drink.
If you do have prediabetes, you can prevent it from turning into diabetes. People can delay diabetes for a decade or more just by making lifestyle changes, studies show. Those changes include:
- Eat low-calorie, low-fat meals.
- Exercise to lose 5% to 7% of your body weight. Your routine should include at least 5 half-hour aerobic sessions (such as a brisk walk) and a few bouts of strength training (such as lifting light weights) each week.
People who still have high blood sugar levels after changing their diet and exercise habits may need diabetes medicines to bring them down. But for most people, lifestyle changes can prevent diabetes if you start making them early.