Millions Have High Blood Sugar Right Now and Don't Even Know It

A Silent Condition With Loud Consequences

You might feel a little tired. Maybe you've been thirsty more than usual, or you've noticed your vision seems slightly off. These are easy symptoms to brush aside — but dietitians say they could be your body sending a serious warning signal about your blood sugar.

The signs and symptoms of elevated blood sugar are easy to ignore, mistake, or miss — and this is especially true for type 2 diabetes, which can go undiagnosed for many years. The scale of the problem is staggering. Over 40 million Americans, or 12% of the population, are living with diabetes — and of those 40.1 million people, 11 million are undiagnosed. Even more alarming, 115.2 million Americans have prediabetes, but 8 in 10 adults with prediabetes don't know they have it.

"Many people with mild to moderately high blood sugar, especially in prediabetes or early type 2 diabetes, may have no noticeable symptoms at all," says Jackie Topol, M.S., RD, CDN, a New York City-based registered dietitian and prediabetes expert. High blood sugar develops gradually, and during early stages, it's often not severe enough to be recognized by classic symptoms.

The Sneaky Symptoms You Might Be Dismissing

One of the most common — and commonly overlooked — warning signs is the combination of unquenchable thirst and frequent bathroom trips. The reason: "Excess sugar in the blood results in the kidneys working harder to get rid of it," says Maria Elena Fraga, RD, CDCES, CDN, a registered dietitian with Mount Sinai New York-Concierge Care. When the kidneys can't keep up, extra sugar spills into the urine, taking fluids from the body's tissues along with it — causing dehydration and a persistent feeling of thirst. Drinking more fluids to quench that thirst then leads to even more urination.

Fatigue is another red flag that gets chalked up to a busy lifestyle. Diabetes can make you feel very tired — a condition called fatigue — because high blood sugar disrupts the body's ability to use sugar for energy. If you're feeling tired and lacking energy even after getting enough rest, it may be a sign of high blood sugar. Then there's blurry vision, which many people attribute to aging or screen time. When blood glucose levels spike, you may notice blurry vision that comes and goes throughout the day — because high sugar causes the lens in your eye to absorb extra fluid and swell, changing how light focuses on your retina.

Slow-healing cuts and wounds round out the list of subtle clues. High blood sugar affects circulation and immune function, delaying the body's healing process — and it can also lead to more frequent infections, especially of the skin and urinary tract. Diabetic neuropathy, or nerve damage, is a serious complication of uncontrolled type 2 diabetes, and tingling, numbness, or a "pins and needles" sensation in the extremities may signal nerve damage that, if left untreated, could become permanent.

Why Early Action Changes Everything

The encouraging news is that catching these signs early makes a real difference. Early intervention can help, says Mary Ellen Phipps, M.P.H., RDN, LD, author of The Easy Diabetes Cookbook. Next steps include seeing a clinician for A1C and glucose testing, starting targeted lifestyle changes with medication if needed, and seeking urgent care for red flags like confusion, vomiting, fruity breath, or trouble breathing.

If you have prediabetes, losing weight by eating healthy and being more active can cut your risk of getting type 2 diabetes in half. Lifestyle changes like a balanced diet can help manage or prevent high blood sugar. The key is not waiting until symptoms become impossible to ignore — because by then, the condition may have already been progressing silently for years.

When to Talk to a Doctor

Dietitians stress that none of these symptoms on their own are definitive proof of high blood sugar — but a pattern of several of them together warrants a conversation with a healthcare provider. If you're experiencing two or more symptoms — especially fatigue, excessive thirst, or blurred vision — it's time to get your blood sugar levels tested. A simple blood test measuring fasting glucose or HbA1c can provide answers quickly.

The broader takeaway is one of awareness. Millions of people are walking around with blood sugar levels that are quietly doing damage, unaware that their body has been sending signals all along. Recognizing those signals — and acting on them — is the difference between catching a manageable condition early and facing a far more difficult road ahead.