According to the CDC, 37.3 million of the US population—over 11 percent—are living with diabetes. “Diabetes happens when you have too much sugar, also called glucose, in your blood,” says Adrian Vella, MD. “Normally, when your body digests food, sugar goes into your bloodstream then into your cells, where it serves as fuel for those cells. Sugar gets into the cells with the help of the hormone insulin. When you eat, your pancreas secretes insulin into your bloodstream. As insulin circulates, it acts like a key that allows sugar to enter your cells and lowers the amount of sugar in your blood. In people with diabetes and prediabetes, this process doesn’t work the way it should. Instead of fueling your cells, sugar builds up in your bloodstream.”

If left untreated, diabetes can lead to serious health conditions. “Many people don’t know they have high blood glucose levels until they are diagnosed with type 2 diabetes. Often at this point, they’ve had it for some time,” says endocrinologist Athena Philis-Tsimikas, MD. “Knowing your risk factors and the early signs of type 2 diabetes can help prevent or delay development of this chronic condition that affects millions of people… Type 2 diabetes is more than just a blood sugar disease, however. It is usually accompanied by high blood pressure and high fats, or lipids, in the blood. If this triple threat goes undetected, all three issues can cause health problems.”

Before full-blown type 2 diabetes is diagnosed, prediabetes happens—which should be taken as a serious warning sign. “What it comes down to is this: Prediabetes means that if you do nothing, you’re at high risk of developing type 2 diabetes,” says Jane Jeffrie Seley, DNP, CDE, a diabetes nurse practitioner and certified diabetes educator in the division of endocrinology, diabetes and metabolism at NewYork-Presbyterian/Weill Cornell Medical Center. “Prediabetes equals high risk. Explain it that way and people start to pay attention.” Here are five signs you have diabetes, according to experts. Read on—and to ensure your health and the health of others, don’t miss these Sure Signs You’ve Already Had COVID.

Increased, unexplained thirst is one of the earliest and most common signs of prediabetes and diabetes. “No matter how much you drink, it feels like you’re still dehydrated. Your tissues (such as your muscles) are, in fact, dehydrated when there’s too much glucose (sugar) in your blood,” say Amy Hess-Fischl, MS, RD, LDN, BC-ADM, CDCES, and Lisa M. Leontis RN, ANP-C. “Your body pulls fluid from the tissues to try to dilute the blood and counteract the high glucose, so your tissues will be dehydrated and send the message that you need to drink more. This is also associated with increased urination. Even after you eat, you may still feel very hungry. That’s because your muscles aren’t getting the energy they need from the food; your body’s insulin resistance keeps glucose from entering the muscle and providing energy. Therefore, the muscles and other tissues send a ‘hunger’ message, trying to get more energy into the body.”6254a4d1642c605c54bf1cab17d50f1e

“The classic symptom of being hungry frequently stems from the fact that a person with diabetes cannot utilize glucose well as an energy source within cells,” says James Norman, MD, FACS, FACE. “The glucose is circulating in the blood, but the cells can’t absorb it to use it as a fuel. The excess blood sugar molecules also ‘spill’ into the urine, meaning that as the blood filters through the kidneys, some of the sugar comes out of the blood and is not reabsorbed. The extra sugar which is now in the urine causes water molecules to follow (a normal physics principle) and therefore the person with diabetes urinates frequently (the second classic symptom of diabetes). This obviously leads to the third classic symptom, which is frequently being thirsty. The body can sense that excess water is being lost because of the frequent urinating and the normal response is to become thirsty.”

Fatigue is a common early sign of type 2 diabetes, experts say. “Having your blood sugar go up and down and up and down all day long is exhausting and can leave people with unmanaged blood sugars feeling very tired,” says Mary Ellen Phipps, MPH, RDN, LD. “So one of the best ways to boost energy for diabetes is to focus on regulating blood sugars. Many people don’t realize that your energy levels and how tired you feel (or don’t feel) is very closely related to your blood sugar levels. If you look up the symptoms of both hypoglycemia (low blood sugar) and hyperglycemia (high blood sugar) and you’ll see tiredness and fatigue listed as symptoms for both conditions.” 

Being mindful of blood sugar levels is crucial for people with diabetes to combat fatigue. “So, over long periods of time, poorly managed blood sugars can definitely lead to unexplained tiredness, fatigue, and exhaustion,” Phipps says. “Boosting energy levels when you have diabetes is largely tied to making sure we’re doing everything we can to promote stable blood sugar levels. This goes for people with type 2 diabetes and any other type of diabetes. This is where balancing our meals and snacks with fat, fiber, and protein comes into play.” 

Numbness and tingling in the feet is another common and concerning symptom of diabetes. “More than 30 million Americans are living with diabetes, and peripheral neuropathy, or nerve damage in the feet, is one of the most common—and most serious—complications of the disease,” says podiatrist Thomas F. Vail, DPM. “Nerve damage causes burning, tingling, heaviness or numbness in the feet and affects up to 70 percent of all diabetic patients. Neuropathy can be a rather scary aspect of diabetes because patients may not be able to feel pain. If you can’t feel an injury or sore, it could lead to a serious infection.”

Experiencing nerve damage means people with diabetes must take extra care to not get injured. “If you do experience diabetic nerve damage, foot care becomes even more critical. It starts at home with daily checks on your feet,” Dr. Vail says. “Check your feet for any injuries and for changes to the skin, hair, or even temperature of the skin. If you can’t see your feet well, try propping up a mirror, or ask friends or family for help. I recommend patients with peripheral neuropathy never go barefoot because of the risk of injuries. People with peripheral neuropathy should see a podiatrist regularly to help catch any changes in their foot health early.”

Obesity and diabetes are closely connected, doctors warn. “The epidemic of prediabetes is following the epidemic of obesity,” says Dr. Louis Aronne, director of the Comprehensive Weight Control Center at NewYork-Presbyterian and the Sanford I. Weill Professor of Metabolic Research at Weill Cornell Medicine. “It’s pretty clear that an increase in body weight raises the risk of developing type 2 diabetes. As body weight in the general population has increased, the rate of diabetes has followed in kind.”

One explanation for the link between obesity and diabetes is that fat cells cause insulin resistance. The good news? Losing weight can help manage the symptoms and reverse insulin resistance. “Whatever you weigh to start with, if you lose 5 to 7 percent of your total, you get enormous health benefits,” says Dr. Aronne. “That’s because as your fat cells shrink, an alteration in the production of key hormones improves insulin resistance, inflammation, blood pressure and many other metabolic disorders associated with obesity.”

Blurry vision could be a sign of diabetes, and should never be ignored. “If you’ve had diabetes for a long time or don’t manage and control your blood sugar well, you’re more likely to experience vision complications, including blindness,” says New Orleans optometrist Jarrett Johnson, OD, MPH. “It’s important for everyone. But for people with diabetes or prediabetes, it can play a critical role in preventing or delaying blindness. About 90 percent of diabetes-related vision loss can be prevented, but early detection is key. Get regular comprehensive eye exams, and contact your eye doctor right away if your vision changes suddenly or becomes blurry, spotty, or hazy.

“When you have diabetes, blood vessels in your retina are more likely to leak fluid into the macula, which in turn leads to swelling,” Dr. Johnson explains. “This is called diabetic macular edema, a dangerous condition that can destroy the sharp vision in the macula, leading to partial or complete vision loss… When you have diabetes, however, high blood sugar levels can cause so much damage to the retina’s blood vessels that new ones start to form,” Dr. Johnson says. “And when those new blood vessels grow on your retina or iris, it causes your eye pressure to increase—and results in glaucoma.”