Would you know if you had prediabetes?

More than 38 million Americans are living with type 2 diabetes. While that may seem like a big number, it pales in comparison to this one: 97.6 million. That’s how many American adults have prediabetes, which is when your blood sugar level is higher than normal, but not over the threshold for diabetes.

While prediabetes can be managed or even reversed with lifestyle changes, 81% of people don’t know they have it. And if you don’t know you have it, you can’t take steps to get your blood sugar back into the normal range.

That’s why knowing the symptoms of prediabetes, risk factors, and how it’s diagnosed is so important. But spotting them is tricky, since the signs that your blood sugar is inching upwards can be pretty subtle and most people with prediabetes don’t have any symptoms at all. Here’s more about prediabetes, including why it happens, what to look out for, and what to do about it.

What is prediabetes?

Prediabetes is when you have elevated levels of glucose, or sugar, in your blood. It can be measured three ways:

Fasting plasma glucose (or FPG)

Often run as part of routine blood work, an FPG test provides a basic snapshot of your blood sugar level before you’ve had anything to eat.

• Normal: Less than 100mg/dl
• Prediabetes: 100 mg/dl to 125 mg/dl
• Diabetes: 126 mg/dl and higher

HbA1c (or A1c)

If your doctor suspects you may have prediabetes or diabetes, they might run this test, which provides a two-to-three month average of your blood sugar levels.

• Normal: Less than 5.7%
• Prediabetes 5.8% to 6.4%
• Diabetes: 6.5% and higher

Oral glucose tolerance test

This is the gold standard for diagnosing someone with prediabetes or diabetes. You drink a liquid that contains a specific amount of glucose, then get your blood taken at certain intervals afterwards to measure how well your body moves sugar out of your blood. The level of blood sugar that indicates diabetes or prediabetes depends on which drink you’re given, but your doctor will be able to help translate the results.

What causes prediabetes?

The amount of glucose you have in your blood is determined by many factors, most importantly insulin, a hormone produced in the pancreas that helps cells take glucose from your bloodstream for energy. When you have prediabetes, your cells have trouble responding to the insulin, which causes glucose to build up in the blood. Initially, your body will make additional insulin to overcome this resistance, but as time goes on, your body will ultimately start making less insulin, which causes blood sugar levels to climb even higher, ultimately leading to type 2 diabetes.

“Over time, [too much glucose] can damage the heart, nerves, eyes, kidneys, and more,” says Melissa Joy Dobbins, RDN, CDCES, a registered dietitian and certified diabetes care and education specialist. “These complications can have a very significant impact on a person’s health and quality of life.” And your body might start to experience these negative effects while you’re still in the prediabetes stage. “While blood glucose levels may not yet be high enough for a diagnosis of type 2 diabetes, they are still elevated which can lead to the same complications,” says Dobbins.

Signs of prediabetes

The vast majority of people with prediabetes don’t experience any symptoms at all (this is why it’s so important to know your risk factors and get regularly screened for the disease). But there might be a few subtle signs that something is going on.

• You have no energy. It’s easy to write off fatigue as just something you need to live with, but if you’re getting ample shuteye and still feel beat, talk about it with your doctor. High blood glucose levels is one of the things that might be to blame.

• You get light-headed. If you start to feel jittery or faint, “this is a sign of reactive hypoglycemia, and for some people it’s a very early indicator of prediabetes,” says Dr. Florence Comite, M.D., an endocrinologist and founder of the Comite Center for Precision Medicine & Health Longevity in New York City.

• You don’t bounce back as quickly from illness. If you have prediabetes, your immune system may not react the same way to an infection. This could be due to lower levels of cytokines, which are molecules the immune system uses to send signals, as well as negative changes to the gut microbiome brought on by prediabetes.

Risk factors for prediabetes

While obesity is often the risk factor brought up the most, it isn’t the only thing that can make you more prone to insulin resistance (and you don’t need to have obesity to have prediabetes). “Plenty of thin, active people with balanced diets still get prediabetes and type 2 diabetes,” says Jill Weisenberger, RDN, CDCES, author of Prediabetes: A Complete Guide.

Research shows that the following factors increase your risk of prediabetes:

• You have overweight or obesity. Excess fat tissue and related changes to your metabolism can lead to insulin resistance.

• You are male or over the age of 45. Men tend to store fat in their belly, which is a risk factor for diabetes, and as you age you are likelier to gain weight, also raising your risk.

• Diabetes runs in your family. If a close relative, like a parent or sibling, has diabetes, you have a higher risk of getting prediabetes. This may be due to a combination of genetic factors and the fact that lifestyle habits like diet and physical activity tend to be similar in families.

• You‘re active less than three days a week. As muscles move, they grab glucose from the bloodstream for energy. As a result, those who are less physically active are more prone to high blood sugar levels.

• You had gestational diabetes. Women who have high blood sugar levels while pregnant have a 35% to 60% likelihood of developing type 2 diabetes within five to 10 years of their pregnancy. “If you had even a borderline response, much less a positive response, to a glucose tolerance test while pregnant, you have a higher risk of diabetes now and later,” says Comite.

• You have polycystic ovarian syndrome (PCOS). An estimated 65% to 70% of women with this hormonal disorder have insulin resistance, which may cause high blood sugar levels.

• You’re African American, American Indian, Pacific Islander, or Hispanic/Latino. People of some races and ethnicities are more likely to develop prediabetes. This is likely due to a combination of factors, including genetics and health disparities that affect these populations.

5 ways to manage prediabetes

First things first: If you have risk factors for prediabetes, keep up with your recommended screening schedule. And if your blood sugar is higher than you want it to be, some small lifestyle changes can help prevent the onset of type 2 diabetes and even reverse prediabetes completely.

1. Lose weight. Losing 5% to 7% of your body weight (9 to 13 pounds for a 180-pound person) can prevent or delay the onset of diabetes. That’s where the WeightWatchers Points Program can help. If you have prediabetes, it’s proven to help with weight loss and lowering your glucose levels and is recognized by the CDC as a Diabetes Prevention Program.

2. Get moving. “Being active encourages muscles to better utilize glucose for energy, and makes them more sensitive to insulin,” Dobbins says. One study on people with prediabetes found that a single moderate- to high-intensity workout improved their ability to use insulin by up to 85% for hours afterwards. Physical activity also helps improve circulation, boosts heart and lung health, and can aid in weight loss. If you haven’t been very active, start with walking and slowly work up to 30 minutes of brisk walking, 5 times a week.

3. Rethink your eating patterns. Your diet affects how likely you are to have high blood sugar. “Diets high in red meats and sugar-sweetened beverages are associated with a greater risk of type 2 diabetes,” Weisenberger says. On the flip side, eating more nuts, berries, and yogurt may lower your risk.

4. If you smoke, stop. Cigarettes contain toxic substances that injure cells throughout the body, preventing them from functioning properly. Smoking may also encourage the body to store belly fat, which increases levels of cortisol, a hormone that raises blood sugar levels.

5. Talk with your doctor about medication. If lifestyle changes don’t significantly lower your A1c levels, your doctor may recommend medication. Several studies have shown that the drug metformin, which is prescribed for those with diabetes, can also help prevent prediabetes from progressing to type 2 diabetes.