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Signs You Have Low Blood Sugar and Don't Even Know It

What to know about low blood sugar and signs you have it. 
FACT CHECKED BY Emilia Paluszek

Our body depends on blood sugar for energy and when it's low, chances are you'll notice something off and possibly feel a variety of symptoms. "Glucose, also known as blood sugar, is important because it is the body's main source of fuel, or energy. All cells of the body use glucose in some form for energy and adequate function. It is required for several neurological and chemical functions as well. Glucose is vital to life and balance in the body," Lisa Richards, a nutritionist and author of the Candida Diet tells us. Low blood sugar, or hypoglycemia, is a common condition often linked with diabetes and although our body will usually give off warning signals, sometimes they can be missed. When left untreated, serious health complications can arise, so knowing the signs to watch out for is crucial to your overall well-being. Eat This, Not That! Health spoke with several experts who share what to know about blood sugar and symptoms to be aware of. As always, please consult with your physician for medical advice. Read on—and to ensure your health and the health of others, don't miss these Sure Signs You've Already Had COVID.


What to Know About Blood Sugar

Doctor with glucometer and insulin pen device talking to male patient at medical office in hospital.

Arti Thangudu, MD Triple Board Certified: Endocrinology, Diabetes & Metabolism; Lifestyle Medicine; Internal Medicine, Certified in Plant-Based Nutrition with Complete Medicine tells us, "Normal blood sugar is important to normal functioning of the body's organs. When blood sugar is too low, essential organs like the brain, may shut down, causing a person to pass out or even die. It is important to note that we cannot diagnose hypoglycemia with symptoms or blood sugar alone. To diagnose hypoglycemia a patient must meet Whipple's triad: low serum blood sugar <70 mg/dl, symptoms of low blood sugar, resolution with ingestion of carbs."

Kimberley Rose-Francis, RDN, CDCES, CNSC, LD a diabetes care and education specialist says, "For someone to be healthy, their blood sugar must be within a specific range. According to the American Diabetes Association, a normal range for fasting blood sugar level is 70-100 mg/dL. Any number consistently more or less than this amount may indicate something array is occurring and medical attention is warranted."


Causes of Low Blood Sugar

Young woman measures blood sugar level.

Dr Thangudum says, "By far the most common cause of low blood sugar is use of medications for diabetes like insulin or sulfonylureas. Other medical conditions like cancers and insulin-producing tumors can also cause it. Some people experience hypoglycemia after bariatric surgery. Sometimes people experience hypoglycemia after high carb meals when their pancreas secretes too much insulin for the carbs ingested."

Richards says, "Low blood sugar, also known as hypoglycemia, can occur due to a wide variety of internal or external factors. It is diagnosed as blood sugar under 70 mg/dl and can come on quickly. Some of the more common causes of low blood sugar include skipping meals or not eating at all, a rush of insulin after a meal, pregnancy, and diabetic hypoglycemia."


The Dangers of Untreated Low Blood Sugar

woman in a couch with headache and a hand on forehead

According to Dr Thangudum, "If left untreated, blood sugar can drop very low and affect the brain and heart."

Richards adds, "Low blood sugar can lead to a wide variety of negative side effects ranging from mild to coma or death." 


Low Blood Sugar Signs Can Be Missed


Dr Thangudum shares, "Someone not knowing they have low blood sugar typically occurs in people who have had frequent hypoglycemia due to medications. When a person has experienced frequent hypoglycemia, they develop hypoglycemia unawareness. This means the body doesn't give them the normal signals – clamminess, shaking, sweating, anxiety, hunger – of mild hypoglycemia. Thus they can develop a profound hypoglycemic event that presents only with loss of consciousness or death."



Sad woman in anticipation of an order.

Rose-Francis says, "The gnawing and growling in your stomach is your body's way of telling you it is time to refuel. Your body craves nutrients (carbohydrates, fat, and protein) to function correctly. If these hunger cues go ignored, your body may use up its immediate glucose or sugar stores which may lead to low blood sugar."



Thoughtful girl sitting on sill embracing knees looking at window, sad depressed teenager spending time alone at home, young upset pensive woman feeling lonely or frustrated thinking about problems

According to Rose-Francis, "Low blood sugar can impact your mood and may result in anxiety. Low blood sugar can have a neurologic effect and impact mentation."


Blurry Vision

Rose-Francis says, "Blurred vision may indicate low blood sugar. This may be because low blood sugar impacts the ocular region of the brain."  



Depressed woman awake in the night, she is touching her forehead and suffering from insomnia

Richards says, "Drowsiness can be a sign of low blood sugar as the body struggles to get enough glucose to keep the body adequately energized. When cells do not get the glucose they need to function the body becomes drained." 


Low Blood Sugar in People Who Aren't Diabetic Isn't Common, But Can Happen

Doctor checking blood sugar level with glucometer. Treatment of diabetes concept.

​​Alyssa Wilson, RD with Signos tells us, "Low blood sugar in a non-diabetic is not common and typically not very dangerous. Our liver stores glucose and can also make glucose so it is always at the ready to keep our resting blood glucose levels sufficiently stable. When your blood sugar does drop due to one of the reasons listed above, typically the liver comes to the rescue quickly so that it is not a dangerous situation.  There are some exceptions, such as with certain medications, or liver or kidney dysfunction. If you know you may be predisposed to low blood sugar, you may need to eat a snack such as a piece of fruit and a handful of nuts or a banana with nut butter.

It's important to remember that in the non-diabetic community, it is not typically an emergency to raise the glucose level quickly so drinking juice or eating a hard candy is not always necessary and may even lead to the glucose roller coaster effect and more frequent low blood sugars.

One example of low blood sugar in a non-diabetic is reactive hypoglycemia. This occurs when your body notices a high or fast-rising blood sugar level, and releases more insulin than necessary to counteract it. This results in a dip below your baseline. This type of low blood sugar is typically accompanied by symptoms such as sweating, nausea, shakiness, dizziness, or rapid heart rate. A doctor can diagnose this condition using a Mixed Meal Tolerance Test (MMTT).

Another cause of hypoglycemia (low blood sugar) in non-diabetics is seen with the overconsumption of alcohol. Your body prioritizes what it metabolizes first, based on what's most easily stored. Since your body has no capacity to store alcohol, it gets metabolized first followed by carbs, protein, then fat. This prioritization delays the breakdown of carbs into glucose. This type of low blood sugar can be felt as hunger, sweating, or tiredness.

Because dangerously low blood sugar is not common in the non-diabetic community, these folks are most likely to notice the symptoms, and therefore unlikely to not know that they have low blood sugar. As such, the most common reason that someone without diabetes wouldn't know they have low blood sugar is because they are unaware of the symptoms to look for.

It is important to remember that, in the non-diabetic community, the term "low blood sugar" is relative. For example, if person A has a resting glucose of 95 mg/dL then they could feel some low blood sugar symptoms at 85 mg/dL or even 90 mg/dL, whereas person B may have a resting glucose that is much lower, say 75 mg/dL, so their symptoms wouldn't kick in until 70 mg/dL."

Heather Newgen
Heather Newgen has two decades of experience reporting and writing about health, fitness, entertainment and travel. Heather currently freelances for several publications. Read more about Heather
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