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The #1 Signal Your Blood Sugar is "Dangerously High"

This is what hyperglycemia feels like.
FACT CHECKED BY Emilia Paluszek

High blood sugar–known as hyperglycemia–is a dangerous health condition where blood sugar levels are out of control due to a lack of insulin in the body. Commonly associated with diabetes, high blood sugar can lead to serious complications if left untreated. "Without proper insulin function, your body can't store glucose in your muscles or liver, but neither can it make any fat. Instead, the fat breaks down and produces, among other things, keto acids," says endocrinologist Irl Hirsh, MD. Here are five symptoms of high blood sugar you should never ignore. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


Increased Thirst

Close-up of pretty young woman drinking water from glass

Are you constantly thirsty no matter how much water you drink? This could be a sign of high blood sugar. "No matter how much you drink, it feels like you're still dehydrated," say Amy Hess-Fischl, MS, RD, LDN, BC-ADM, CDCES, and Lisa M. Leontis RN, ANP-C. "Your tissues (such as your muscles) are, in fact, dehydrated when there's too much glucose (sugar) in your blood. 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."


Fatigue and Hunger


If cells cannot process the glucose from your blood, fatigue and excessive hunger will set in, experts say. "If your body isn't making enough insulin – or any at all – or your cells resist your insulin, glucose can't get into the cells," says Mary Johnson, director of Diabetes Quality and Education at Geisinger. "That means you won't have energy and you can feel more tired and more hungry than usual."


Sexual Dysfunction For Both Men and Women

Sad man sitting on a bed, girlfriend in the background.

Unexplained sexual dysfunction could be a sign of high blood sugar. "With both genders, the longer you have diabetes, the more likely you are to experience sexual dysfunction in some way," says endocrinologist Shirisha Avadhanula, MD. "Changes in testosterone or estrogen (because of diabetes, menopause or co-occurring conditions) can impact libido, lubrication and the ability to become sexually aroused. There are treatment options for both men and women. You may not see instant success but keep talking with your care team to move to the next option. There is hope that you can resume an active, enjoyable sex life."


High Blood Pressure

high blood pressure

High blood sugar can impact blood pressure, doctors warn. "Insulin, which plays a role in managing blood glucose, has an unfortunate relationship with nitric oxide production in blood vessels," says Elena Christofides, MD, FACE. "It blocks the ability of the body to make nitric oxide. Nitric oxide is important to blood vessels because it is one of the very few ways to expand the size of the blood vessels and lower blood pressure. If a person with diabetes is using insulin, this severely impairs the ability of the body to lower blood pressure via nitric oxide production, in turn increasing the risk of high blood pressure."


#1 Signal of Hyperglycemia Is Excess Urination


Increased urination during both daytime and at night is a common sign of high blood sugar, doctors warn. "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," says James Norman, MD, FACS, FACE. "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)." And to protect your life and the lives of others, don't visit any of these 35 Places You're Most Likely to Catch COVID.

Ferozan Mast
Ferozan Mast is a science, health and wellness writer with a passion for making science and research-backed information accessible to a general audience. Read more about Ferozan