Diabetic hypoglycemia - Symptoms and causes (2023)


Diabetic hypoglycemia occurs when someone with diabetes doesn't have enough sugar (glucose) in his or her blood. Glucose is the main source of fuel for the body and brain, so you can't function well if you don't have enough.

For many people, low blood sugar (hypoglycemia) is a blood sugar level below 70 milligrams per deciliter (mg/dL), or 3.9 millimoles per liter (mmol/L). But your numbers might be different. Ask your health care provider about the appropriate range to keep your blood sugar (target range).

Pay attention to the early warning signs of hypoglycemia and treat low blood sugar promptly. You can raise your blood sugar quickly by eating or drinking a simple sugar source, such as glucose tablets, hard candy or fruit juice. Tell family and friends what symptoms to look for and what to do if you're not able to treat the condition yourself.


Early warning signs and symptoms

Initial signs and symptoms of diabetic hypoglycemia include:

  • Looking pale (pallor)
  • Shakiness
  • Dizziness or lightheadedness
  • Sweating
  • Hunger or nausea
  • An irregular or fast heartbeat
  • Difficulty concentrating
  • Feeling weak and having no energy (fatigue)
  • Irritability or anxiety
  • Headache
  • Tingling or numbness of the lips, tongue or cheek

Nighttime signs and symptoms

If diabetic hypoglycemia occurs when you're sleeping, signs and symptoms that may disturb your sleep include:

(Video) Hypoglycemia: Definition, Identification, Prevention, and Treatment

  • Damp sheets or nightclothes due to perspiration
  • Nightmares
  • Tiredness, irritability or confusion upon waking

Severe signs and symptoms

If diabetic hypoglycemia isn't treated, signs and symptoms of hypoglycemia worsen and can include:

  • Confusion, unusual behavior or both, such as the inability to complete routine tasks
  • Loss of coordination
  • Difficulty speaking or slurred speech
  • Blurry or tunnel vision
  • Inability to eat or drink
  • Muscle weakness
  • Drowsiness

Severe hypoglycemia may cause:

  • Convulsions or seizures
  • Unconsciousness
  • Death, rarely

Symptoms can differ from person to person or from episode to episode. Some people don't have any noticeable symptoms. It's also possible you won't have any symptoms of hypoglycemia. It's important to monitor your blood sugar levels regularly and keep track of how you're feeling when your blood sugar is low.

When to see a doctor

Severe hypoglycemia can lead to serious problems, including seizures or unconsciousness, that require emergency care. Make sure your family, friends and co-workers know what to do in an emergency.

Inform people you trust about hypoglycemia. If others know what symptoms to look for, they might be able to alert you to early symptoms. It's important that family members and close friends know where you keep glucagon and how to give it so that a potentially serious situation can be easier to safely manage. Glucagon is a hormone that stimulates the release of sugar into the blood.

Here's some emergency information to give to others. If you're with someone who is not responding (loses consciousness) or can't swallow due to low blood sugar:

  • Don't inject insulin, as this will cause blood sugar levels to drop even further
  • Don't give fluids or food, because these could cause choking
  • Give glucagon by injection or a nasal spray
  • Call 911 or emergency services in your area for immediate treatment if glucagon isn't on hand, you don't know how to use it, or the person isn't responding

If you have symptoms of hypoglycemia several times a week or more, see your health care provider. You may need to change your medication dosage or timing, or otherwise adjust your diabetes treatment regimen.

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Low blood sugar is most common among people who take insulin, but it can also occur if you're taking certain oral diabetes medications.

Common causes of diabetic hypoglycemia include:

  • Taking too much insulin or diabetes medication
  • Not eating enough
  • Postponing or skipping a meal or snack
  • Increasing exercise or physical activity without eating more or adjusting your medications
  • Drinking alcohol

Blood sugar regulation

Most of the body's glucose comes from food. The hormone insulin lowers blood sugar (glucose) levels when blood sugar is too high. If you have type 1 or type 2 diabetes and need insulin to control your blood sugar, taking more insulin than you need can cause your blood sugar level to drop too low and result in hypoglycemia.

Your blood sugar can also drop too low if, after taking your diabetes medication, you eat less than usual, or if you exercise more than you typically do, which uses extra glucose. Maintaining the balance between insulin, food and activity isn't always easy. But your health care provider, certified diabetes care and education specialist, and registered dietitian can work with you to try to prevent low blood sugar levels.

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Risk factors

Some people have a greater risk of diabetic hypoglycemia, including:

  • People using insulin
  • People taking diabetes drugs called sulfonylureas, such as glipizide (Glucotrol), glimepiride (Amaryl) or glyburide (Diabeta, Glynase)
  • Young children and older adults
  • Those with impaired liver or kidney function
  • People who've had diabetes for a long time
  • People who don't feel low blood sugar symptoms (hypoglycemia unawareness)
  • Those taking multiple medications
  • Anyone with a disability that prevents a quick response to falling blood sugar levels
  • People who drink alcohol


If you ignore the symptoms of hypoglycemia too long, you may lose consciousness. That's because your brain needs glucose to function. Recognize the signs and symptoms of hypoglycemia early, because if untreated, hypoglycemia can lead to:

  • Seizures
  • Loss of consciousness
  • Death

Take your early symptoms seriously. Diabetic hypoglycemia can increase the risk of serious — even deadly — accidents.


To help prevent diabetic hypoglycemia:

  • Monitor your blood sugar. Depending on your treatment plan, you may check and record your blood sugar level several times a week or multiple times a day. Careful monitoring is the only way to make sure that your blood sugar level remains within your target range.
  • Don't skip or delay meals or snacks. If you take insulin or oral diabetes medication, be consistent about the amount you eat and the timing of your meals and snacks.
  • Measure medication carefully and take it on time. Take your medication as recommended by your health care provider.
  • Adjust your medication or eat additional snacks if you increase your physical activity. The adjustment depends on the blood sugar test results, the type and length of the activity, and what medications you take. Follow your diabetes treatment plan when making adjustments.
  • Eat a meal or snack with alcohol, if you choose to drink. Drinking alcohol on an empty stomach can cause hypoglycemia. Alcohol may also cause delayed hypoglycemia hours later, making blood sugar monitoring even more important.
  • Record your low glucose reactions. This can help you and your health care team identify patterns contributing to hypoglycemia and find ways to prevent them.
  • Carry some form of diabetes identification so that in an emergency others will know that you have diabetes. Use a medical identification necklace or bracelet and wallet card.

By Mayo Clinic Staff

(Video) Hypoglycemia Symptoms (WITHOUT DIABETES) + What to Do About It!


What is the primary cause of hypoglycemia? ›

Causes of hypoglycaemia

The most common reasons are the person has: taken too much insulin or medication. done more exercise or more intense exercise than usual. missed a meal or not had enough carbohydrate.

What is the most common cause of hypoglycemia in diabetics? ›

Common causes of diabetic hypoglycemia include: Taking too much insulin or diabetes medication. Not eating enough. Postponing or skipping a meal or snack.

What are the 3 P's of hypoglycemia? ›

The main symptoms of diabetes are described as the three polys - polyuria, polydipsia, and polyphagia.

What are the three classic signs of hypoglycemia? ›

Symptoms of hypoglycemia can also include:
  • Being pale.
  • Feeling weak.
  • Feeling hungry.
  • A higher heart rate than usual.
  • Blurred vision.
  • Confusion.
  • Convulsions.
  • Loss of consciousness.

What can be mistaken for hypoglycemia? ›

  • Amenorrhea.
  • Atherosclerosis.
  • Bone Cancer.
  • Brain Cancer.
  • Cataracts.
  • Diabetes Mellitus.
  • Food Poisoning.
  • Glaucoma.

Which disease is caused by hypoglycemia? ›

Hypoglycemia is common in people with diabetes, especially people who take insulin to manage the condition. One study found that 4 in 5 people with Type 1 diabetes and nearly half of all people with Type 2 diabetes who take insulin reported a low blood sugar episode at least once over a four-week period.

Can hypoglycemia be caused by stress? ›

You may not realize it, but becoming severely stressed can trigger adrenal fatigue, which can lead to hypoglycemia. This is because several adrenal hormones including cortisol, epinephrine, and norepinephrine play critical roles in the regulation of your body's blood sugar levels.

What is one of the warning signs of hypoglycemia? ›

Common symptoms may include:
  • Fast heartbeat.
  • Shaking.
  • Sweating.
  • Nervousness or anxiety.
  • Irritability or confusion.
  • Dizziness.
  • Hunger.

What is one of the first symptoms of hypoglycemia syndrome? ›

Symptoms usually occur when blood sugar levels fall below four millimoles (mmol) per litre. Typical early warning signs are feeling hungry, trembling or shakiness, and sweating. In more severe cases, you may also feel confused and have difficulty concentrating.

What symptoms would confirm a suspicion of hypoglycemia? ›

Symptoms may include:
  • Sweating (almost always present). Check for sweating on the back of your neck at your hairline.
  • Nervousness, shakiness, and weakness.
  • Extreme hunger and slight nausea.
  • Dizziness and headache.
  • Blurred vision.
  • A fast heartbeat and feeling anxious.

Why do Type 2 diabetics get low blood sugar? ›

In type 2 diabetes, the pancreas doesn't make enough insulin, or your body can't use it properly. Too much insulin or oral diabetic medication can lower the blood sugar level, leading to hypoglycemia.

Can stress cause hypoglycemia in diabetics? ›

It is important to be aware that repeated episodes of stress can cause serious changes in blood sugar levels, making it harder for diabetics to manage their condition and increasing the risk of hypoglycemia (low blood sugar).

What 6 things may identify hypoglycemia? ›

Low blood sugar (hypoglycaemia)
  • sweating.
  • feeling tired.
  • dizziness.
  • feeling hungry.
  • tingling lips.
  • feeling shaky or trembling.
  • a fast or pounding heartbeat (palpitations)
  • becoming easily irritated, tearful, anxious or moody.

Which organ is most affected by hypoglycemia? ›

The brain is one of the first organs to be affected by hypoglycemia. Shortage of glucose in the brain, or neuroglycopenia, results in a gradual loss of cognitive functions causing slower reaction time, blurred speech, loss of consciousness, seizures, and ultimately death, as the hypoglycemia progresses.

What is the rule of 15 for hypoglycemia? ›

For low blood sugar between 55-69 mg/dL, raise it by following the 15-15 rule: have 15 grams of carbs and check your blood sugar after 15 minutes. If it's still below your target range, have another serving. Repeat these steps until it's in your target range.

When should I worry about hypoglycemia? ›

Low blood sugar is called hypoglycemia. A blood sugar level below 70 mg/dL (3.9 mmol/L) is low and can harm you. A blood sugar level below 54 mg/dL (3.0 mmol/L) is a cause for immediate action.

Can you reverse hypoglycemia? ›

In the short term, if you are hypoglycemic you can take steps to bring your blood glucose back to normal with a small serving of a quick sugar food such as fruit juice, honey, soda, milk, or hard candy. In the long-term, you have to cure the condition causing it.

What is the best bedtime snack for hypoglycemia? ›

Eating a light snack close to bedtime will help keep your blood sugar stable throughout the nighttime hours. Try these: a high-protein, low-sugar brand of Greek yogurt coupled with berries and walnuts. a no-sugar vegetable smoothie.

Does hypoglycemia show up in blood work? ›

Fasting or reactive hypoglycemia is diagnosed by a blood test to measure blood glucose. The test may be performed after fasting overnight, physical activity, or between meals.

What damage does hypoglycemia cause? ›

Hypoglycemia commonly causes brain fuel deprivation, resulting in functional brain failure, which can be corrected by raising plasma glucose concentrations. Rarely, profound hypoglycemia causes brain death that is not the result of fuel deprivation per se.

What toxins cause hypoglycemia? ›

Toxic induced hypoglycemia is usually caused by the anti-diabetic treatment and excessive alcohol consume. Hypoglycemia in diabetics treated with insulin or anti-diabetic oral agents is far the most studied form of hypoglycemia.

What are the long term effects of hypoglycemia? ›

Long-term effects

Hypoglycemia can also increase the risk of other conditions, including: eye disease. kidney disease. nerve damage.

What are the 6 signs of hypoglycemia? ›

Low blood sugar (hypoglycaemia)
  • sweating.
  • feeling tired.
  • dizziness.
  • feeling hungry.
  • tingling lips.
  • feeling shaky or trembling.
  • a fast or pounding heartbeat (palpitations)
  • becoming easily irritated, tearful, anxious or moody.

What helps hypoglycemia immediately? ›

If you have hypoglycemia symptoms, do the following: Eat or drink 15 to 20 grams of fast-acting carbohydrates. These are sugary foods or drinks without protein or fat that are easily converted to sugar in the body. Try glucose tablets or gel, fruit juice, regular (not diet) soda, honey, or sugary candy.

What causes hypoglycemia in non diabetics? ›

Hypoglycemia, or low blood sugar levels, can also occur in people without diabetes. Possible causes include alcohol use, certain medications, severe infections, and serious issues affecting your organs.

What are severe symptoms of hypoglycemia? ›

If hypoglycemia becomes severe, you may not be able to safely swallow food or drink. By this point, your blood glucose level is less than 54 mg/dL—often below 40 mg/dL. You may feel very confused, pass out, or have a seizure. Without prompt treatment, severe hypoglycemia may lead to a coma or even death.

What is the best drink for hypoglycemia? ›

  • 1/2 cup apple juice.
  • 1/2 cup orange or grapefruit juice.
  • 1/2 cup pineapple juice.
  • 1/2 cup regular soda (not diet)
  • 1/3 cup grape juice.
  • 1/3 cup cranberry juice.
  • 1/3 cup prune juice.
  • 1 cup fat free milk.

When should you go to the ER for hypoglycemia? ›

If a person experiencing hypoglycemia becomes unconscious, a person should call 911.

How long does a hypoglycemic episode last? ›

Hypoglycemia caused by sulfonylurea or long-acting insulin may take longer to resolve but usually goes away in one to two days.


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