High blood sugar has a way of sneaking up on people. In my part of the Midwest, I’ve known more than a few neighbors who chalked their symptoms up to “just getting older,” a busy harvest season, or too many church suppers in a row, only to learn later that their blood sugar had been running far too high. The trouble is, the first warning sign is not always dramatic. Quite often, it starts with being unusually thirsty, and from there the body begins sending other signals that are easy to brush aside.

I’m not a doctor, but after many years of cooking for a family, helping loved ones manage diabetes, and learning to pay attention to what the body whispers before it starts shouting, I can tell you this: those little signs matter. Below are 12 common warning signs of high blood sugar, along with practical steps to take, what numbers to know, and when it’s time to call a medical professional right away.

1. Unusual thirst is often the first warning sign

If there’s one symptom I’ve seen show up again and again, it’s thirst that seems out of proportion to the day. Not the kind you get after mowing 3 acres in July or salting a ham, but a steady dry feeling that has you refilling your glass every hour. High blood sugar pulls fluid out of the body’s tissues. When glucose builds up in the bloodstream, the kidneys try to filter out the extra sugar, and that process uses more water.

If you find yourself drinking far more than usual for 2 or 3 days in a row, take note. A rough benchmark many doctors use for fasting blood sugar is 70 to 99 mg/dL as typical, 100 to 125 mg/dL as prediabetes range, and 126 mg/dL or higher on more than one test as diabetes range. If excessive thirst is paired with a home glucose reading over 200 mg/dL, it deserves prompt medical attention.

2. Frequent urination, especially at night

When there’s too much sugar in the blood, the kidneys work overtime to get rid of it through urine. That often means more trips to the bathroom, and many people first notice it overnight. If you’re getting up 2, 3, or 4 times a night when that’s not normal for you, it may not just be age or an extra cup of tea after supper.

One practical thing to do is keep a simple 3-day log: how much you drink, how many times you urinate, and whether you’re waking at night. Bring that to a doctor or clinic. Patterns tell a story. If frequent urination comes with vomiting, weakness, confusion, or signs of dehydration like dizziness and a very dry mouth, seek urgent care.

3. Fatigue that feels heavy and persistent

There’s everyday tired, and then there’s that dragging, washed-out fatigue where even simple chores feel harder than they should. When blood sugar stays high, the body has trouble using glucose properly for energy. So even if plenty of sugar is circulating in the bloodstream, the cells are not getting what they need efficiently.

I’ve known folks who thought they were simply worn down from farm work or poor sleep, only to discover their glucose was elevated. If your fatigue lasts more than 1 or 2 weeks, especially with thirst, urination, or blurry vision, it’s worth asking for blood work. A fasting glucose test and an A1C test can give a much clearer picture. An A1C of 6.5% or higher can indicate diabetes.

4. Blurry vision that comes and goes

High blood sugar can cause fluid shifts in the lenses of the eyes, which can make vision blur. Sometimes people notice they can read fine one day and then struggle the next, or road signs seem fuzzier than usual. It may come and go at first, which is exactly why people often put off getting it checked.

Don’t ignore changes in vision. Sudden or severe blurring should be evaluated promptly, especially if it happens alongside a glucose reading over 240 mg/dL or symptoms like headache and weakness. And if you already have diabetes, routine eye exams matter a great deal because long-term high blood sugar can damage the tiny blood vessels in the eyes.

5. Increased hunger, even after eating

One of the stranger signs is feeling hungry soon after a meal. You’ve had breakfast, maybe eggs, toast, and fruit, yet by 10 o’clock you feel hollow again. When glucose can’t move into the cells properly, the body still acts as though it’s short on fuel, and hunger can rise.

What to do? Build meals around steadier foods: 20 to 30 grams of protein, high-fiber vegetables, and moderate portions of carbohydrates. For example, instead of a breakfast of sweet cereal and juice, try 2 eggs, 1 slice of whole-grain toast, and a half cup of berries. That won’t diagnose anything, but it may help reduce rapid spikes while you arrange an appointment.

6. Dry mouth and dry skin

When the body is losing extra fluid through urination, the mouth and skin often show it. Lips may feel parched, the tongue may feel sticky, and skin can seem less supple than usual. In winter, we Midwesterners are used to dry skin from cold wind and furnace heat, but dryness all year long can be a clue that something else is going on.

Hydration helps, but if the dryness is caused by high blood sugar, water alone won’t fix the root problem. Sip water regularly, avoid sugary drinks, and check labels. A 20-ounce bottle of regular soda can contain 50 to 65 grams of sugar, which can send blood glucose up quickly. If symptoms continue, ask your doctor for a glucose screening.

7. Slow-healing cuts and scrapes

Small injuries that linger can be another warning sign. A nick from pruning tomatoes, a cracked heel, or a scraped knuckle should gradually improve over days. With high blood sugar, healing may take longer because circulation and immune function can be affected.

This is especially important for the feet. Check them daily if you already have diabetes or suspect a blood sugar problem. Look for cracks, blisters, redness, or sores. Wash with lukewarm water, dry carefully, and moisturize dry skin, but not between the toes. If a wound is not improving after 2 to 3 days, or if redness spreads, contact a clinician.

8. More frequent infections

High blood sugar can make it easier for yeast and bacteria to grow, and it can make it harder for the immune system to do its job well. Some people notice repeated yeast infections, more urinary tract infections, or skin infections that keep returning.

If you’ve had 2 or more similar infections within a few months, particularly alongside thirst, fatigue, or frequent urination, mention that pattern to your doctor. It may not be high blood sugar, but it absolutely deserves a closer look. Repeated infections are one of those clues that can connect the dots when seen together.

9. Tingling or numbness in the hands or feet

This symptom tends to show up more often after blood sugar has been high for a while, but sometimes it’s the complaint that finally gets a person into the clinic. Tingling, burning, or numbness in the feet or fingertips can signal nerve irritation or damage.

I always tell people not to wait on this one. If your socks feel oddly bunched when they’re not, or your feet burn at night, write it down and get checked. Early treatment of blood sugar problems can help prevent more nerve damage. Good shoes, daily foot checks, and keeping glucose in target range can make a real difference over time.

10. Unexplained weight loss

Some folks are surprised to learn that weight loss can be a warning sign of high blood sugar. If the body can’t use glucose properly, it may begin breaking down fat and muscle for energy instead. That can lead to pounds dropping off without trying.

Losing 5 to 10 pounds over a short period, especially if your appetite is the same or greater than usual, is worth bringing up. It may feel flattering for about a minute, but unplanned weight loss is not something to brush aside. When it appears together with heavy thirst or fatigue, make an appointment soon.

11. Headaches, trouble concentrating, and irritability

Blood sugar swings can affect the brain as well as the body. Some people describe feeling foggy, short-tempered, or unable to focus on ordinary tasks. A recipe they’ve made for 30 years suddenly feels hard to follow, or balancing the checkbook takes twice as long.

These symptoms are common to many conditions, so on their own they don’t prove high blood sugar. But when they happen with increased thirst, urination, and tiredness, they belong in the conversation. Keeping a symptom log for 1 week can help a doctor sort out what’s happening. Note time of day, meals, drinks, and any home glucose readings.

12. Nausea, fruity-smelling breath, or deep fatigue can mean an emergency

This last sign is the one I most want folks to respect. Very high blood sugar can become dangerous, especially if it leads to diabetic ketoacidosis, more common in type 1 diabetes but also possible in other situations. Warning signs can include nausea, vomiting, stomach pain, fruity-smelling breath, rapid breathing, deep weakness, confusion, or severe dehydration.

If someone has these symptoms, don’t wait to “see how they feel in the morning.” Seek emergency care right away. A blood sugar reading over 240 mg/dL with vomiting, confusion, or trouble breathing needs urgent attention. This is not the time for home remedies or guesswork.

What to do if you notice these signs

Start simple and act promptly. Call your doctor, a local clinic, or an urgent care center and ask about testing. The usual tests may include a fasting blood glucose, an A1C, or sometimes an oral glucose tolerance test. If you have access to a home glucose meter, follow the directions carefully and write down the results with dates and times.

In the meantime, drink water instead of sweet tea, regular soda, fruit punch, or energy drinks. Build meals around non-starchy vegetables, beans, eggs, fish, chicken, plain yogurt, oats, and whole grains in modest portions. A short walk of 10 to 15 minutes after meals can help some people lower post-meal blood sugar, though anyone feeling faint or ill should rest and get medical advice first.

Numbers and habits that are useful to know

For many adults, common screening numbers are these: fasting glucose under 100 mg/dL is considered normal, 100 to 125 mg/dL may indicate prediabetes, and 126 mg/dL or higher on repeat testing may indicate diabetes. An A1C under 5.7% is typical, 5.7% to 6.4% suggests prediabetes, and 6.5% or higher may indicate diabetes. Your doctor may give you different targets depending on age, pregnancy, medications, or other health conditions.

It also helps to know where sugar hides. One large bakery muffin can contain 35 to 50 grams of carbohydrate. A flavored coffee drink can carry 30 to 60 grams. Even foods that sound wholesome, like granola or bottled smoothies, can add up quickly. Reading labels is not glamorous, but it is mighty useful.

When not to wait

Please don’t put off care if symptoms are stacking up. If you have extreme thirst, constant urination, blurred vision, and unusual fatigue, make an appointment as soon as you can. If you also have vomiting, confusion, weakness so severe you can’t manage normal tasks, or trouble breathing, go in right away.

I’ve lived long enough to know that people often try to be brave when what they really need is help. High blood sugar is one of those things that can often be managed much better when it’s caught early. Listen to the small warnings. The body is often kinder than we realize, sending signals before serious trouble arrives.