What is Hypoglycaemia?

Hypoglycaemia (low blood glucose) occurs when blood glucose drops below target, usually below 4 mmol/L. It is important to talk to your diabetes care team about your individual target for what is too low for you. Hypoglycaemia is often referred to as a hypo. It can occur to someone if they take too much insulin.

Low blood glucose needs to be treated right away, so it is important to learn the symptoms of low blood glucose.

What Causes Hypoglycaemia?

Here are some causes of low blood glucose:

  • If you have Type 1 diabetes, you may have taken too much insulin, or you need to decrease your insulin dose
  • If you have Type 2 diabetes, you may be taking an oral medicine that can cause low blood glucose and the dose needs to be adjusted
  • You eat less than planned
  • You exercise more than planned or you did not have a snack before the activity
  • Stress can cause low blood glucose for some people
  • Alcohol

What are the Symptoms of Low Blood Glucose?

  • Shaky
  • Sweaty
  • Feeling nervous or anxious
  • Being irritable or impatient
  • Rapid heartbeat
  • Dizzy
  • Hunger or nausea
  • Sleepy
  • Blurred vision
  • Headache
  • Anger, sadness
  • Nightmares or crying during sleep
  • Seizure
  • Unconsciousness

How is Low Blood Glucose Treated?

It is always best to check blood glucose to confirm that you are having a hypo. Immediately have 15-20 grams of a simple carbohydrate or sugar. Recheck your blood glucose in 15 minutes. If low blood glucose continues, repeat. If your next planned meal or snack is more than an hour away, have a small snack to keep your blood glucose in target until your next time to eat.

Here are some examples of 15-20 grams of carbohydrate that are good to treat low blood glucose:

  • 3-4 glucose tablets
  • 1 small tube glucose gel
  • 2 tablespoons of raisins
  • 4 ounces of juice or a fizzy sugary drink
  • 1 tablespoon of sugar or honey
  • 8 ounces of milk
  • 5 hard sweets, jellybeans, gumdrops


If low blood glucose is not treated it can lead to seizure or unconsciousness. Someone will have to help you if you cannot treat the low blood glucose yourself.

Glucagon is a hormone that is also made in the pancreas. It helps stored sugar get into your blood stream when your blood glucose is too low. Glucagon can also be injected. Glucagon injection kits are available by prescription.

The patient and the people who are most often with the patient should learn the symptoms and treatment of low blood glucose and learn how to use a glucagon kit, in the event of a severe low blood glucose.

What is Hypoglycaemia Unawareness?

Some people with diabetes may not feel or recognise the symptoms of hypoglycaemia. Hypoglycaemia unawareness occurs more frequently in people who have had a lot of low blood glucose episodes. In these people, the symptoms of low blood glucose are not recognised until very low blood glucose levels are reached. If you have hypoglycaemic unawareness, you may become severely low, which can lead to confusion, loss of consciousness, seizures and even death. People with hypoglycaemic unawareness often need to rely on others to recognise and treat their low blood glucose.

Hypoglycaemia unawareness happens more often in those who:

  • Have a lot of low blood glucose
  • Have had diabetes a long time
  • Tightly control their blood glucose

If you have, or think you have, hypoglycaemia unawareness talk to your diabetes care team to help you avoid low blood glucose.


The information on this site is intended to provide you with information about Ascensia Diabetes Care’s products and is not a substitute for professional medical advice or treatment for specific medical conditions.  Any questions or concerns you have regarding diabetes or a medical condition should always be discussed with a qualified medical professional.

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