What Causes Low Blood Sugar Without Diabetes?

While it’s less common, low blood sugar can impact people without diabetes. 

Low blood sugar usually isn’t life-threatening. However, in some cases, it can become serious and lead to injury.

Keep reading to find out what causes low blood sugar without diabetes, and how to treat and prevent it.

Preventing and treating low blood sugar is similar regardless of whether you have diabetes, and is the most important part of low blood sugar management.

What is low blood sugar?

A healthy person’s blood sugar levels are primarily regulated by their pancreas, liver, and several hormones. Your pancreas releases insulin to lower blood sugar when it’s high, and your liver releases stored sugar to help prevent low blood sugar.

A normal blood sugar range falls between 70-140 mg/dL (milligrams per deciliter). Low blood sugar, or hypoglycemia, occurs when your blood sugar (blood glucose) drops below 70 mg/dL. 

Low blood sugar can be mild, moderate, or severe. Severe hypoglycemia can become life-threatening if it isn’t treated quickly.

Low blood sugar usually affects people with diabetes taking medications to help lower their blood sugar. Insulin and sulfonylureas are the two main diabetes medications that can cause low blood sugar. However, you can get low blood sugar even if you don’t have diabetes.

There are different levels of hypoglycemia, which correlate with the severity of low blood sugar.

Level 1 (mild) hypoglycemia

Blood glucose is less than 70 mg/dL but is 54 mg/dL or higher.

Level 2 (moderate) hypoglycemia

Blood glucose is less than 54 mg/dL.

Level 3 (severe) hypoglycemia

A person cannot function because of mental or physical changes, and they need help from another person. In this case, blood glucose is often below 40 mg/dL.

What are the symptoms of low blood sugar?

If you don’t experience low blood sugar very often, you’ll likely notice distinct symptoms when you become hypoglycemic. These symptoms arise when your adrenal glands (located on top of your kidneys) release epinephrine and cortisol hormones in response to hypoglycemia. 

If you get low blood sugar often, you might develop hypoglycemia unawareness (1). Hypoglycemia unawareness is a complication where you don’t experience the typical warning signs of low blood sugar. 

People who have had diabetes for a long time or have a history of recurrent low blood sugar are more likely to develop hypoglycemia unawareness.

The most common symptoms of hypoglycemia include:

• Feeling shaky and/or dizzy
• Irregular heartbeat
• Pale skin
• Fatigue
• Tingling or numbness of the lips, tongue, or cheek
• Sweating
• Hunger
• Feeling irritable or moody
• Feeling anxious or nervous
• Headache

Some people experience nocturnal hypoglycemia, which is when low blood sugar occurs overnight. Nocturnal hypoglycemia can be even more dangerous because you aren’t awake and may not notice the symptoms. 

Signs of nocturnal hypoglycemia include:

• Damp sheets or nightclothes from sweating due to low blood sugar
• Nightmares
• Feeling tired, irritable, or confused after waking up

If hypoglycemia isn’t treated, it can become a low blood sugar emergency. Signs and symptoms of severe hypoglycemia include:

• Clumsiness or jerky movements
• Muscle weakness
• Slurred speech or difficulty speaking
• Blurred vision or double vision
• Drowsiness
• Confusion
• Convulsions or seizures
• Unconsciousness/fainting
• Coma

What causes low blood sugar without diabetes?

While diabetes is the most common cause of low blood sugar, there are other causes as well.

Physical activity and/or weight loss

Physical activity stimulates your body to take up more glucose for energy which can cause low blood sugar, especially if you don’t eat enough carbohydrates during long periods of exercise.

Your liver stores sugar in the form of glycogen (2). Glycogen stores provide sugar to your body during periods of fasting, stress, and exercise. 

Glycogen stores help prevent you from getting low blood sugar. However, prolonged periods of exercise or fasting can deplete glycogen stores and lead to hypoglycemia.

Weight loss can also use up glycogen stores, especially if you’re following a very low-carbohydrate diet. Without adequate glycogen stores, your body can’t correct low blood sugar on its own as efficiently.

Heavy alcohol use

Drinking alcohol is one of the causes of low blood sugar in people without diabetes. Alcohol is metabolized in your liver, the same organ that releases stored sugar. Alcohol metabolism takes priority, which reduces the rate at which your liver releases and makes new sugar stores (3).

Light to moderate alcohol use isn’t typically associated with low blood sugar. However, binge drinking or other alcohol abuse can result in low blood sugar.

Reactive hypoglycemia

Some people develop low blood sugar after eating, which is reactive hypoglycemia. In those cases, the pancreas releases too much insulin in response to blood sugar levels rising after eating. 

Reactive hypoglycemia without diabetes is a relatively rare condition and is usually associated with other health conditions (4).

Certain medications

Some medications used in people without diabetes sometimes causes low blood sugar. Some of these medications include:

• Beta-blockers (such as atenolol or propranolol overdose)
• Cibenzoline and quinidine (heart arrhythmia drugs)
• Indomethacin (a pain reliever)
• Drugs that fight infections (such as gatifloxacin, levofloxacin, pentamidine, quinine, trimethoprim-sulfamethoxazole)

Gastric bypass surgery

Gastric bypass surgery and other bariatric weight loss surgeries have increased by an estimated 37% from 2011 to 2018. Certain types of bariatric surgery can lead to a condition called dumping syndrome.

Dumping syndrome causes food to be rapidly released from your stomach into your small intestines, triggering an exaggerated insulin response and low blood sugar (5).

Kidney disease

Severe kidney disease can cause low blood sugar without diabetes. If you undergo dialysis to treat your kidney disease, you may be especially prone to low blood sugar due to malnutrition. 

Some types of dialysis increase your blood sugar and then cause a rebound drop in blood sugar from too much insulin being released.

Because of the risk of low blood sugar, patients with advanced kidney disease and diabetes often have less strict blood sugar targets than those without kidney disease (6).

Pancreatic tumor

Your pancreas secretes insulin, the hormone that helps lower your blood sugar. Too much insulin can cause low blood sugar.

Tumors on your pancreas can cause low blood sugar without diabetes. An insulinoma is a tumor that makes more insulin than you need, resulting in low blood sugar. 

The causes of insulinomas are unknown but may be associated with other abnormalities involving your endocrine system (the system involving hormone secretion).

Is it normal for non-diabetics to have low blood sugar?

Low blood sugar is never considered normal, even for people with diabetes. While it’s not alarming to have a rare single bout of low blood sugar, frequent low blood sugar signals that something isn’t right and should be evaluated by a healthcare professional.

What can cause false low blood sugar readings?

You might sometimes develop low blood sugar symptoms when your blood sugar levels are normal. False low blood sugar is more common among people newly diagnosed with diabetes and beginning treatment. 

If your blood sugar was usually around 300 mg/dL and it lowers to 150 mg/dL, you might feel symptoms of low blood sugar even though 150 mg/dL is actually still slightly high.

Treating low blood sugar

If you think you’re experiencing low blood sugar, you should consult your healthcare provider and obtain a glucometer or glucose meter, a machine that measures your blood sugar levels with a small drop of blood.

Testing your blood sugar when you’re experiencing symptoms is the most accurate way to determine if you’re experiencing low blood sugar and, if so, how severe it is.

If your blood sugar is less than 70 mg/dL and you have symptoms of low blood sugar, you should treat it as soon as possible.

Eating/drinking carbohydrates

If your blood sugar is below 70 mg/dL, it should be treated by eating or drinking something containing 15 grams of carbohydrates. 

Fruit juice and candies are ideal since they are quickly absorbed into your bloodstream. It doesn’t take much juice to treat low blood sugar – about one-half cup of juice contains around 15 grams of carbohydrates.

Glucose tablets

Glucose tablets or glucose gels are a popular treatment for low blood sugar because they’re easy to have on hand in different situations. They dissolve quickly and provide pure glucose, so they are rapidly absorbed into your bloodstream to raise blood sugar quickly. 

They are available over the counter without a prescription. Keep glucose tablets in your car, purse, or with you when you’re exercising if you’re prone to low blood sugar.

After treating your low blood sugar, you should re-check your blood sugar again in 15 minutes, if possible. 

If your blood sugar levels aren’t increasing enough, you should repeat the treatment and retest your blood sugar in another 15 minutes. Repeat this process until blood sugar is at your target level (usually at least 70 mg/dL). 

If your blood sugar isn’t increasing enough or your symptoms persist or worsen, you should notify your healthcare provider.

What to avoid if you have low blood sugar

Not eating enough before & during exercise

Over-exercising, especially without eating enough carbohydrates before or during exercise, can cause low blood sugar in some people.

If you’re prone to low blood sugar, you’ll need to plan ahead when it comes to exercise. If you’re exercising for more than an hour, bring a source of carbohydrates with you to replenish depleted glycogen stores. 

Sports drinks, energy chews, or even dried fruit are all convenient ways to provide carbohydrates and prevent low blood sugar.

Drinking sugary drinks

If you have rebound or reactive hypoglycemia, your body makes too much insulin in response to a rise in your blood sugar. Drinking sugary drinks like soda, sweetened teas, coffee, and fruit-flavored drinks cause your blood sugar level to rise very quickly. 

Sharp increases in blood sugar trigger rebound hypoglycemia from the large amount of insulin released by your pancreas.

Very low-carbohydrate diets & fasting

If you’re prone to low blood sugar, you might want to avoid periods of prolonged fasting, as well as very low-carb diets. Your body makes blood sugar the most efficiently from carbohydrates, which are its preferred energy source.

If you follow a very low-carb diet such as a ketogenic diet, you might experience more frequent bouts of hypoglycemia if you were already prone to it.

Drinking a lot of alcohol

As mentioned earlier, drinking alcohol can result in low blood sugar. If you’re prone to low blood sugar and want to have a drink, be sure to eat a carbohydrate-containing meal or snack before having your drink. Avoid binge drinking, which is especially problematic for causing low blood sugar.

How to prevent low blood sugar

The best way to manage low blood sugar is through prevention. 

Eat carbohydrates consistently

Carbohydrates are one of three primary macronutrients, along with protein and fat. Unlike protein and fat, carbohydrates (carbs) turn into sugar when digested. 

Sources of carbohydrates include grains, fruit, legumes, vegetables (some have more carbs than others, like potatoes), and dairy products like milk and yogurt. 

Sugar is a type of carbohydrate, so any sugar-sweetened food or drink also falls under this category, whether it’s sugar, honey, agave nectar, or any other type of sweetener.

Eat protein with carbohydrates

Eating protein with carbohydrates helps slow the rise in your blood sugar levels. Examples of protein (which don’t raise blood sugar levels like carbohydrates) include meat, eggs, cheese, soy products like tofu, nuts and nut butters, and seeds.

If you have reactive hypoglycemia, eating protein with carbohydrates is essential. Even if you don’t have reactive hypoglycemia, eating protein with carbs can help make you feel fuller and more satisfied, and may help reduce sugar cravings. 

Eating crackers (carb) with cheese (protein) or peanut butter (protein) with toast (carb) are some examples.

Check your blood sugar

You can check your blood sugar with a glucometer even if you don’t have diabetes. Glucometer kits can be purchased over the counter and can be useful for identifying blood sugar trends. 

Checking your blood sugar when you start to feel symptoms can help you identify and treat the low early.

Combining blood sugar readings along with a food and symptom log/journal can help you identify the causes of your low blood sugar. 

Conclusion

Low blood sugar is most common in people with diabetes who are taking diabetes medications like insulin injections and sulfonylureas. However, you can still develop low blood sugar even if you don’t have diabetes.

Treating the potential underlying causes of low blood sugar without diabetes should be the first step. After that, the best way to manage low blood sugar is through prevention. 

Eat carbohydrates consistently, avoid binge drinking alcohol, eat a snack before and even during exercise, and monitor your blood sugar with a glucometer to identify trends in your blood sugar levels.

Explore More

Hypoglycemia Diet: How to Prevent Low Blood Sugar.