10 Signs and Symptoms of Low Blood Sugar

Managing your blood glucose (sugar) levels with type 1 diabetes or type 2 diabetes can feel like a balancing act. 

You don’t want your blood glucose to be too high, nor do you want it to be too low. 

Unlike high blood glucose levels, which often don’t have symptoms, low blood sugar is associated with several common symptoms.

Being aware of low blood sugar symptoms can help you quickly identify low blood sugar and treat it promptly.

The quicker you can treat low blood sugar, the less likely you are to experience complications from it.

What is a Low Blood Sugar Level?

Insulin levels primarily influence your blood sugar levels. Insulin is a hormone that helps blood sugar enter your cells from your bloodstream. Too much insulin can cause low blood sugar. 

A normal blood sugar range is between 70 and 140 mg/dL. It can become problematic if your blood glucose level consistently falls above or below this range.

A low blood sugar level is defined as being less than 70 mg/dL. Having low blood sugar (blood glucose) is called hypoglycemia. You might not feel symptoms of low blood sugar levels until it falls below that threshold, or you might feel symptoms at a slightly higher blood sugar level. So what are symptoms of low blood sugar? Here is a quick overview (we will go into more detail further down).

Symptoms of Low Blood Sugar

  • Fast heartbeat (changing from rapid heartbeat)
  • Shaking
  • Sweating
  • Nervousness or anxiety
  • Irritability or confusion
  • Dizziness
  • Hunger

When you feel low blood sugar symptoms will depend on several factors such as how long you’ve had diabetes, your normal blood glucose level, history of low blood glucose, and more.

Low blood sugar levels can arise from too much insulin or other diabetes medication, not eating enough, and too much exercise, among other factors.

 Causes of Low Blood Sugar Without Diabetes

 In some cases, people may experience low blood sugar symptoms without diabetes. Although this is rare, here are some causes of non diabetic hypoglycemia:

  • Reactive hypoglycemia or postprandial hypoglycaemia (this is when your body releases too much insulin after a meal)
  • Fasting hypoglycemia
  • Malnutrition
  • Gastric bypass surgery
  • Certain medications, such as quinine for malaria or antiviral hepatitis C medications
  • Other medical conditions (such as hormone problems, pancreas problems, liver problems, kidney disease, heart/blood flow and blood vessels problems, or adrenal dysfunction)

What Causes Low Blood Sugar in People With Diabetes?

  • Diabetes medications can lead to low blood sugar. This includes a group of medications called sulfonylureas, like glibenclamide and gliclazide. It also includes glinide medications, such as repaglinide and nateglinide. 
  • Delaying or skipping meals
  • Not eating enough carbs at your last meal (such as bread, cereal, fruit, pasta, and potatoes)
  • Exercise (especially intense exercise)
  • Drinking alcohol

low blood sugar symptoms

Types of Low Blood Sugar 

Nighttime low blood sugar

While low blood sugar can happen at any time during the day, some people may experience low blood sugar while they sleep. Reasons this may happen include:

  • Having a strenuous and tiring day
  • Taking too much insulin
  • Drinking alcohol late at night
  • Being physically active before bed

Eating regular meals and not skipping them can help you avoid nighttime low blood sugar. Eating when you drink alcohol can also help. If you think you’re at risk for low blood sugar overnight, have a snack before bed.

You may wake up when you have low blood sugar, but you shouldn’t rely on that. One method is using a Continuous Glucose Monitor (CGM). This will alert you if your blood sugar drops while you are sleeping.

Severe low blood sugar

As your low blood sugar gets worse, you may experience more serious symptoms, including:

  • Feeling weak and fatigue
  • Feeling confused
  • Having trouble walking or seeing clearly.
  • Having seizures

People with diabetes may experience low blood sugar as often as once or twice a week. Knowing how to identify and treat hypoglycemia is an important part of diabetes management.

What is a dangerous level of blood sugar? 

Hypoglycemia is broken down into different levels of severity. 

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.

Hypoglycemia can become dangerous at any range, but it’s especially dangerous when it drops below 60 mg/dL.

Most people will experience low blood sugar symptoms once their blood sugar level falls below 70 mg/dL. Some people have hypoglycemia unawareness which is when they don’t feel low blood sugar symptoms as soon as they should. 

Hypoglycemia unawareness can lead to severely low blood sugar. The main risk factor for developing hypoglycemia unawareness is having repeated low blood sugar incidents in the past. The more often you experience low blood sugar, the less likely your body will respond to hypoglycemia symptoms.

Some risk factors for developing hypoglycemia include:

  • Use of certain diabetes medications that lower blood sugar, especially insulin.

  • Heavy exercise

  • Erratic eating patterns/skipping meals

  • Advanced age

  • Weight loss (improves insulin sensitivity so can lower blood sugar)

  • Drinking alcohol

  • Having advanced kidney disease

So why is low blood sugar dangerous? Untreated hypoglycemia can lead to seizures, loss of consciousness, coma, and death.

Low blood sugar can also contribute to falls, injuries, and car accidents. Low blood sugar is linked with a greater risk of dementia in older people.

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10 Symptoms Of Low Blood Sugar

1) Sweating 

Some people experience nocturnal hypoglycemia, which is when low blood sugar occurs overnight while you’re sleeping. Nocturnal hypoglycemia is potentially even more dangerous because you aren’t awake and alert, so you likely won’t notice symptoms of low blood sugar. 

Signs of nocturnal hypoglycemia include:

  • Damp sheets or nightclothes from sweating due to low blood glucose 

  • Having nightmares

  • Feeling tired, irritable, or confused after you wake up.

Sweating is a general low blood sugar symptom that can occur while you’re awake as well. You might feel clammy and sweaty even if it’s not hot out if your blood glucose level is falling.

2) Fatigue

When glucose can’t get into your cells, they don’t have the energy they need, which can cause fatigue. 

You might also feel tired when your blood glucose level is high, so you’ll want to check your blood sugar when you’re feeling tired to know what’s going on.

Similar to hypoglycemia, you might feel tired when your blood sugar is high because sugar cannot enter your cells to provide energy

3) Hunger

Cells are starved without enough glucose to feed them. If you’re experiencing low blood sugar, you might notice you feel hungry as a response.

4) Shakiness

Along with sweating and hunger, shakiness is a common low blood sugar symptom. When your blood glucose level falls, your body releases stress hormones such as epinephrine (adrenaline) and norepinephrine to raise your blood sugar. These hormones can cause tremors and feelings of shakiness.

5) Rapid heartbeat

Low blood sugar causes your body to release stress hormones. These stress hormones (including adrenaline) cause anxiety symptoms, such as increased heartbeat.

6) Feeling irritable

Extreme blood sugar changes can trigger anger, moodiness, or sadness in some people. Mood changes might not be as accurate as other physical symptoms, so you should always check your blood sugar to be sure.

7) Tingling lips

It’s not exactly clear why tingling lips are a symptom of low blood sugar in adults, but you might notice tingling in your face or lips if you’re experiencing hypoglycemia.

8) Brain fog

Your brain needs glucose for fuel. If your blood glucose level is low, your brain doesn’t have enough energy to function correctly. This can result in “brain fog” or feeling like you can’t think straight or focus well.

9) Clumsy movements and confusion

Severe hypoglycemia can make you appear drunk even if you haven’t had any alcohol. 

Slurring your speech, stumbling, and not making sense when you talk are all low blood sugar symptoms that you shouldn’t ignore.

10) Vision changes

Low blood sugar can cause blurry vision or double vision. You can also experience vision changes when your blood sugar is high, which is why checking your blood sugar at the onset of low blood sugar symptoms is so important.

How to manage your blood sugar levels

Check your blood sugar level regularly.

The best way to become familiar with your blood sugar trends is to check your blood glucose. Checking your blood glucose regularly will help you identify how you respond when your blood sugar is high or low.

People who check their blood sugar regularly tend to have better blood glucose control compared to those who don’t.

Take medications as prescribed.

Certain diabetes medications can cause low blood sugar. The most common diabetes medications with a risk of hypoglycemia are insulin and sulfonylureas. Avoid changing your medication doses on your own, which might cause low blood sugar. 

If you have type 1 diabetes or type 2 diabetes and you take insulin, your risk of low blood sugar is greater than people taking only oral medications.  Type 2 diabetes low blood sugar symptoms are the same as Type 1 diabetes.

Insulin is the most effective medication at lowering blood sugar, which is why it comes with a risk of hypoglycemia.

Be ready to treat low blood sugar.

Mild low blood sugar can be treated with fruit juice, glucose tablets, and hard candies. If you’re prone to low blood sugar or take insulin, keep these things on hand at home, in your car, at work, and while out exercising. 

More severe low blood sugar is treated with a glucagon injection. Glucagon is a hormone that helps raise your blood sugar. You need a prescription for glucagon, which is an injectable medication. 

Eat carbohydrates consistently.

Carbohydrates are a type of nutrient that raises blood glucose levels. Try to eat carbohydrate meals and snacks consistently throughout the day to promote stable blood sugar

Eating a carbohydrate-heavy meal and then a very small carbohydrate amount at the next can cause blood sugar spikes and crashes.

Be mindful of how exercise impacts your blood sugar.

Exercise can help lower blood glucose, so it’s so beneficial to help manage your diabetes. If you exercise on an empty stomach, you might experience low blood sugar. Aim to have a meal or snack around one hour before exercising to avoid low blood sugar.

Hypoglycemia Prevention 

If you have diabetes, you can make some more easy changes to maintain healthy blood sugar levels.

  • Eat three meals a day, with healthy snack in between.
  • Double-check your insulin and diabetes medicine dosage before hand.
  • Enjoy regular exercise, 30 minutes to 1 hour after meals. Before exercising, make sure you check your blood sugars before and after exercise.
  • Drink alcohol moderately and be sure to monitor your blood sugar levels before and after you drink.
  • Wear a diabetes identification bracelet.

If you don’t have diabetes, ask your doctor if you need to adjust what you eat or how much you exercise. Eat small meals and snacks every few hours.

  • Include protein, fatty, and high-fiber foods in your diet.
  • Limit foods high in sugar and processed foods.
  • Consult with your doctor to determine if anything else could be causing your low blood sugar levels.


If you were wondering ‘what are the symptoms of low blood sugar’, there you have it! We have covered it in some depth. If you have type 1 diabetes or type 2 diabetes and are taking insulin, you’ll likely experience hypoglycemia at one point or another. 

Mild hypoglycemia usually doesn’t result in serious complications, but it can turn into severe hypoglycemia if left untreated. 

Being aware of low blood sugar symptoms is the best way to prevent health issues that can arise from more serious low blood sugar.

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  1. Morales J, Schneider D. Hypoglycemia. Am J Med. 2014 Oct;127(10 Suppl):S17-24. https://pubmed.ncbi.nlm.nih.gov/25282009/

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