Hypoglycemia (Low Blood Glucose)

A condition in which a person’s blood sugar (glucose) level is lower than the standard range is known as Hypoglycemia. Hypoglycemia is mostly related in terms with diabetes but sometimes low blood glucose level may also occur due to other reasons.

Hypoglycemia requires immediate treatment. When the glucose level drop below 70 mg/dL, it is low blood sugar. Low blood sugar is especially common in people with type 1 diabetes.

What are the symptoms of Hypoglycemia?

The signs and symptoms of low blood sugar level (hypoglycemia) may include:

  • Paleness in looks
  • Shakiness
  • Hunger or nausea
  • Sweating
  • Headache
  • An irregular or fast heartbeat
  • Extreme tiredness
  • Irritability or anxiety
  • Dizziness or
  • lightheadedness

In some cases, the signs and symptoms of a worsening hypoglycemia may be as:

  • Confusion, inability to complete daily tasks
  • Slurred speech
  • Blurry vision or tunnel vision

Severe hypoglycemia below 54 mg/dL may cause the following symptoms:

  • Loss of consciousness/passing out or seizures

What Causes Hypoglycemia

Possible causes in people with diabetes:

The most common reason for low blood sugar is owing to diabetes medication.

In case of diabetes, either a person does not make insulin (type 1 diabetes) or they might be less responsive to it (type 2 diabetes). As a result, glucose builds up in the bloodstream and may increase substantially. Insulin or other medications are prescribed to prevent this from happening thereby lowering blood sugar levels. Sometimes, though, too much insulin or other diabetes medications could also result in the blood sugar level dropping too much, causing hypoglycemia.

This may also occur in cases such as:

  • Eating less than usual after taking your regular dose of diabetes medication,
  • Exercising more than what is generally done in routine practice
  • Drinking alcohol with diabetes medication

Possible causes in people without diabetes:

Hypoglycemia in people without diabetes is much less common, but it could happen on account of the following causes:

  • Medications: Accidentally taking someone else’s oral diabetes medication or other medications such as quinine (Qualaquin), used to treat malaria may cause hypoglycemia, especially in children or in people with kidney failure.
  • Excessive alcohol drinking: Drinking heavily without eating
  • Some critical illnesses: Such as severe hepatitis or cirrhosis, severe infection, kidney disease, and advanced heart disease can cause hypoglycemia.
  • Long-term starvation: Malnutrition and starvation in the absence of enough food intake may deplete the glycogen stores the body needs to create glucose.
  • Insulin overproduction: A rare tumor of the pancreas (insulinoma) may cause excessive production of insulin, resulting in hypoglycemia.
  • Hormone deficiencies: Tumours of certain glands (adrenal and pituitary) that regulate glucose production or metabolism

Mealtime hypoglycemia:

Also known as reactive hypoglycemia, mealtime hypoglycemia results due to too much insulin in your blood and usually happens a few hours after the meal. Other causes may be:

  • Having prediabetes or being more likely to have diabetes
  • Stomach surgery
  • Rare enzyme defects

How is Hypoglycemia diagnosed?

A general physical exam and medical history is noted by the doctor. Any history of diseases or stomach surgery will be also asked by the doctor. Blood glucose level is noted especially in case of symptom presentation.

In case the doctor suspects hypoglycemia, they may ask you to fast until symptoms are seen all the while measuring sugar levels at at different times throughout the fast.

To check for reactive hypoglycemia, a test called a mixed-meal tolerance test (MMTT) is conducted where the patient is asked to consume a special drink designed to raise the blood glucose while checking for the levels over the next few hours.

Sometimes, repeated episodes of hypoglycemia over time can lead to hypoglycemia unawareness. The body and brain no longer produce signs and symptoms for low blood sugar, such as shakiness or irregular heartbeats (palpitations). This may increase the risk of severe, life-threatening hypoglycemia and in such cases, the doctor might modify the treatment to raise blood sugar level goals and recommend blood glucose awareness training. A device called continuous glucose monitor (CGM) may also be suggested for some people to alert them when the blood sugar is too low.

How is Hypoglycemia treated?

In case of diabetes: Regularly check the blood sugar level in case of diabetes and if found below target level or below 70 mg/dL, eat or drink 15 to 20 grams of carbohydrates. This could be in the form of juice, or hard candy. The blood sugar should be checked again in 15 minutes and treated every 15 minutes until the levels are ok. Call an ambulance or visit the emergency ward if the levels are not back up.

In the case of non-diabetes: Long-term solution of treating hypoglycemia depends on its cause; surgery in case of tumour, or medication adjustment if that is the cause.

For a quick fix, eat or drink 15 grams of carbohydrates, in the form of juice, glucose tablets, or hard candy. Patients with severe hypoglycemia may require a glucagon injection or intravenous glucose, or FDA – approved medications.

How can hypoglycemia be prevented?

  • – Eat at least three evenly spaced meals each day with between-meal snacks as prescribed in the meal care plans.
  • – Exercise 30 minutes to 1 hour after meals in case of a new regimen, check sugar levels before and after exercise
  • – Drink alcohol in moderation and monitor the blood sugar levels.
  • – Test the blood sugar as directed by your doctor.
  • – Carry an identification bracelet that says a person is diabetic. This is important in case a person faints from hypoglycemia.

What things should you be careful about when you have low blood sugar?

  • – Hypoglycemia may make a person pass out (faint) and in that case, he/she may require a glucagon shot to be given. Glucagon is a prescription medicine that raises blood sugar and is prescribed in severe hypoglycemia. Let the family members and friends know about how to give the shot.
  • – Don’t drive in case of hypoglycemia as it could be dangerous to you and others. If hypoglycemia hits while driving, pull off the road, check your blood sugar, and eat sugary food. Wait at least 15 minutes, check your blood sugar, and repeat these steps if needed before driving.


  1. Mary Jo DiLonardo. Hypoglycemia (Low Blood Sugar). WebMD. February 2024.
  2. Hypoglycemia. Mayo Clinic. February 2024.
  3. Hypoglycemia (Low Blood Sugar). Centers for Disease Control and Prevention. February 2024.

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