10 Signs of High Blood Sugar to Be Aware Of

You might think it would be obvious if you had high blood sugar, but it’s actually entirely possible for signs of high blood sugar to fly under the radar. There are a lot of people who don’t realize they have high blood sugar, so if this is the case for you, you certainly aren’t alone.

As of 2018, more than 34 million people in the U.S. are living with diabetes, the condition that occurs when your blood sugar is too high, either as a result of insulin resistance (in the case of type 2 diabetes) or as a result of your pancreas not making any or enough insulin (in the case of type 1 diabetes), according to the Centers for Disease Control and Prevention (CDC). But 21% of adults with diabetes are unaware they have the disease, according to the CDC. In addition to that, there are about 88 million U.S. people—or more than one in three adults—who have prediabetes, which occurs when blood sugar is higher than normal but not high enough to be called diabetes, and only 15% of adults with the condition reported that a health professional had diagnosed them with the illness, the CDC says.

“We have so many individuals at high risk today in the U.S. who are unaware,” Betul Hatipoglu, M.D., an endocrinologist at the Cleveland Clinic, tells SELF. Given this situation, it is vital to know the signs of high blood sugar and to seek medical care if you experience them, Dr. Hatipoglu says (along with getting tested if you are asymptomatic but have risk factors).

With that in mind, here are the signs of high blood sugar you should be aware of, and what to do if you’re experiencing them.

What Is High Blood Sugar?

High blood sugar (or hyperglycemia) occurs when there’s a buildup of excess glucose in the bloodstream. This is more often a concern for someone with diabetes than it is for someone without it. Our bodies are typically pretty great at keeping our blood sugar in perfect balance, Deena Adimoolam, M.D., assistant professor of endocrinology at the Icahn School of Medicine at Mount Sinai, tells SELF. But in some situations, like when a person has diabetes, high blood sugar can happen.

Blood sugar (also called blood glucose) is measured in milligrams per deciliter (mg/dL), and a fasting blood sugar of greater than 125 mg/dL is considered hyperglycemic, the Cleveland Clinic says. A person can also be considered to have hyperglycemia if their blood glucose level is higher than 180 mg/dL one to two hours after eating, the Cleveland Clinic says.

Healthy Blood Sugar

Normally when the glucose that comes from the food we eat enters the bloodstream, the pancreas secretes just the right amount of insulin, the hormone your body needs to help move glucose from the bloodstream into the body’s cells for energy use or storage, the NIDDK explains. This keeps the amount of glucose in the blood within a pretty tight range. “A person who has no problem with their ability to control blood glucose should never become significantly hyperglycemic,” Dr. Adimoolam says.

A fasting blood sugar level of less than 100 mg/dL is considered normal in people without diabetes, according to the American Diabetes Association (ADA).

Low Blood Sugar

Low blood sugar—known in the medical community as hypoglycemia—happens when your blood sugar level drops below normal, according to the National Institutes of Health (NIH). A fasting blood sugar of 70 mg/dL or lower usually indicates low blood sugar, the Mayo Clinic says.

High Blood Sugar Causes

You may be thinking that hyperglycemia can happen just from eating a super-sugary food, but it’s not really as simple as that. Sure, eating a lot of sugar or carbs can elevate your blood sugar level, but that’s typically when your pancreas kicks into gear and creates insulin to move that glucose into cells throughout the body.

But when someone has diabetes, this finely tuned system gets thrown out of whack. In type 2 diabetes—which accounts for 90% to 95% of diabetes in adults, according to the CDC—the body either can’t make enough insulin or can’t utilize insulin well, according to the NIDDK. If someone has prediabetes, their blood glucose will be higher than normal but not quite in the type 2 diabetes range yet, per the NIDDK. And in type 1 diabetes, the body does not make insulin or makes very little.

In any case, the result is extra sugar hanging around the bloodstream, making you feel like total crap in the short term and putting your health at risk in the long term.

Signs of High Blood Sugar

Someone who has been diagnosed with diabetes will be familiar with how it feels to have hyperglycemia. (If you have diabetes, you can also keep tabs on your blood sugar by testing it regularly.) But for the millions of people who have diabetes or prediabetes and are unaware of it, knowing the signs of high blood sugar could prompt them to seek care and get a diagnosis as soon as possible.

While type 1 diabetes symptoms can come on suddenly and severely, it’s important to note that type 2 diabetes symptoms can creep up gradually and be so mild that they’re not noticeable, the NIDDK explains. And most people with prediabetes actually have no symptoms, per the NIDDK. So it’s extremely important to get screened if you have risk factors, like having a family history, being overweight, or being over age 45, the NIDDK says.

Still, there are many potential signs of high blood sugar in the short and long term that it doesn’t hurt to be conscious of, especially if you are at elevated risk.

Early on, hyperglycemia can make you feel off in a variety of ways:

1. Fatigue

Feeling tired may be the most common early sign of high blood sugar, Dr. Hatipoglu says. It’s also one that can occur, to a mild degree, with even the mild and normal blood sugar fluctuations that happen in people without diabetes (or with prediabetes) when they consume a large amount of simple carbs, like sugar, she says.

Of course, tiredness is a pretty nonspecific symptom (and can even be a sign of low blood sugar, as Dr. Adimoolam points out). If you notice fatigue regularly occurring right after you eat, though—especially a carb-heavy meal—it may have to do with rising blood sugar levels. “People will say, ‘I want to nap after lunch,’ or ‘I just cannot open my eyelids after dinner,’ often after eating something like a lot of pasta or potatoes or sweets,” Dr. Hatipoglu says. To be clear, there’s nothing wrong with eating these foods. But if you notice that they always affect you in a very specific way that you find troubling, like always making you incredibly sleepy, it’s a sign you may want to talk to a medical professional.

2. Frequent urination

When you have too much sugar in your blood, “your kidneys start trying to pour out more sugar to get rid of it. And as they excrete the sugar, they pull out water with it,” Dr. Hatipoglu explains. This makes you have to visit the bathroom more than usual.

3. Increased thirst

This is a natural effect of peeing more, Dr. Adimoolam explains, because your body becomes dehydrated. “People start feeling thirsty all the time,” Dr. Hatipoglu says. The dehydration also becomes cyclical, the Mayo Clinic explains: The more you pee, the thirstier you are, the more you drink, the more you pee, and so on.

4. Headaches

Dehydration from any cause can trigger headaches, Dr. Hatipoglu says. Of course, headaches can be a sign of many different things, but it’s worth getting checked out if it’s something new or coupled with other symptoms here. (The dehydration can also worsen your fatigue in addition to your headaches, by the way.)

5. Blurred vision

When there is excess sugar in the blood, it can affect some unexpected areas in the body, like your eyes, according to the Cleveland Clinic. Essentially, extra sugar (along with a little water) gets trapped in the lens in the middle of the eye, causing a blurred effect, Dr. Hatipoglu explains. (This is temporary and not the same as the damage to the eye that can occur in the long term with a condition like diabetes.)

6. Nausea, vomiting, confusion, and more

These seemingly disparate symptoms are all signs of a rare and life-threatening state called diabetic ketoacidosis (DKA), according to the U.S. National Library of Medicine. DKA can cause the symptoms above, as well as stomach pain, trouble breathing, dry or flushed skin, fruity-smelling breath, or difficulty paying attention. It usually occurs in people with type 1 diabetes and is sometimes the first sign they are sick, according to the U.S. National Library of Medicine. (More rarely, DKA can occur to a milder degree in type 2 diabetes.)

DKA happens when the liver is unable to use the sugar in the blood for energy without insulin and begins to break down body fat into a type of fuel called ketones at such a high rate that they become toxic and make the blood acidic, the U.S. National Library of Medicine explains. DKA can be fatal if left untreated, so anyone experiencing these symptoms should seek care immediately.

Over time, untreated high blood sugar can cause additional symptoms, such as:

7. Recurrent infections

Consistent hyperglycemia can weaken the body’s immune response, according to the CDC. This makes it harder for your body to fight off some infections, making them more frequent, lingering, or serious.

Dr. Hatipoglu especially tends to see frequent yeast infections in people with vaginas who have diabetes. This is because excess sugar from high blood sugar spilling out through the urine helps feed the bacteria that can cause these infections, the NIDDK says. Diabetes can also make you more prone to UTIs, according to the CDC.

8. Slow-Healing sores

High blood sugar levels can affect your body’s circulatory system as well, Dr. Hatipoglu says, impairing blood flow and the body’s ability to heal itself. Sores that take a while to heal, often on the feet, are a common sign of this decreased circulation, according to the Mayo Clinic.

9. Dental issues

Glucose is present in your saliva as well as your blood. When there’s too much of it, it helps harmful bacteria in your mouth grow and combine with food particles to create plaque, the NIDDK explains. This leads to issues like tooth decay, cavities, gingivitis, gum disease, and bad breath. Swollen, tender, and bleeding gums are one of the first things to look out for.

10. Tingling hands and feet

Over the years, hyperglycemia can begin to impact nerve function and eventually cause nerve damage, called neuropathy, Dr. Hatipoglu says. The most common kind of neuropathy is peripheral, according to the NIDDK, which affects the extremities. You might start noticing feelings of tingling, numbness, or burning in your hands, feet, arms, and legs, per the Mayo Clinic.

When to See a Doctor

If you’re experiencing one or many of these symptoms enough for it to raise a mental red flag or affect your life (like because you’re too tired to make it through the day), that’s a sign that you should talk to a doctor about your concerns. An expert like a primary care provider can help determine if high blood sugar due to diabetes or prediabetes is the cause of your symptoms. Even if you’re not sure that’s exactly what’s going on, it’s still worth having a conversation with your doctor about hyperglycemia and other possible causes behind your symptoms.

Diagnosis

If your doctor suspects you might have diabetes, they may order testing. Per the Mayo Clinic, these tests can include:

A glycated hemoglobin (A1C) test. This is a blood test that determines your average blood sugar level for the past two to three months. It measures how much blood sugar is attached to hemoglobin, which is a protein in your red blood cells that carries oxygen. An A1C level of 6.5% or higher on two separate tests indicates that you have diabetes. An A1C between 5.7 and 6.4% indicates prediabetes. Below 5.7% signals that you don’t have these health issues.
A random blood sugar test. This uses a blood sample that’s taken at any time (hence the name). No matter when you ate last, a random blood sugar level of 200 mg/dL or higher suggests diabetes.
A fasting blood sugar test. This is a blood test that’s taken after you fast overnight. A fasting blood sugar level less than 100 mg/dL is in the normal range. A fasting blood sugar level from 100 to 125 mg/dL suggests prediabetes, and if you get a level of 126 mg/dL or higher on two separate tests, it’s a sign of diabetes.
An oral glucose tolerance test. Before taking this test, you need to fast overnight. Then a medical professional will measure your fasting blood sugar level. After that, you drink a sugary liquid and a medical professional tests your blood sugar levels periodically for the next two hours. A blood sugar level less than 140 mg/dL is a normal result, a reading between 140 and 199 mg/dL indicates prediabetes, and 200 mg/DL or higher after two hours suggests that you have diabetes.
A urinalysis. If your doctor thinks you might have type 1 diabetes, they’ll test your urine to look for the presence of those ketones we mentioned, which your body produces when using muscle and fat tissue for energy because there’s not enough insulin to process the available glucose. Your doctor may also want to do a test to see if you have autoantibodies, harmful immune system cells that can signal type 1 diabetes.

Treatment and Prevention

How you treat and prevent high blood sugar depends on the cause and your overall health. But in general, it will almost certainly involve working with your medical team on a plan involving a mix of lifestyle habits and medications to help you best manage your health.

If testing reveals that you have prediabetes, there are things you can do that may help mitigate or even reverse prediabetes and prevent type 2 diabetes, according to the U.S. National Library of Medicine, including exercising, potentially changing your diet (with the guidance of someone like your doctor, an R.D., or a certified diabetes educator), and taking prescribed medication.

If you are diagnosed with type 1 diabetes, your management plan will likely include strategies like testing your blood sugar often (with finger sticks and potentially a continuous glucose monitoring system); taking insulin on a regular basis (via injections or an insulin pump), particularly when you eat carbs or have high blood sugar; and exercising regularly, according to the NIDDK.

If you are diagnosed with type 2 diabetes, you will also have to monitor your blood sugar, make certain lifestyle changes (like working with an expert to come up with a realistic meal plan and exercising), and potentially take medication, Dr. Hatipoglu says.

In both type 1 and 2 diabetes, the best way to prevent high blood sugar is to follow your treatment plan and try to seek medical care if you have questions or if some part of your management plan isn’t working for you.

Additional reporting by Korin Miller.

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