Symptoms of hypoglycaemia 

The symptoms of hypoglycaemia usually begin when your blood glucose level drops below four millimoles (mmol) per litre.

If you have diabetes, particularly if it's treated with insulin, you may be advised to use a small device called a blood glucose meter to regularly check your blood glucose levels.

Symptoms can vary from person to person, and it's important to be aware of the early warning signs so you can treat them.

Signs and symptoms of hypoglycaemia can include:

  • feeling hungry
  • sweating
  • dizziness
  • tiredness (fatigue)
  • blurred vision
  • trembling or shakiness
  • going pale
  • fast pulse or palpitations
  • tingling lips
  • irritability
  • difficulty concentrating
  • confusion
  • disorderly or irrational behaviour, which may be mistaken for drunkenness

If hypoglycaemia isn't treated promptly and your blood glucose levels drop low enough, you may become drowsy or even lose consciousness.

Most people with insulin-treated diabetes notice that the symptoms of hypoglycaemia change and become less obvious the longer they live with the condition.

For some people, the warning symptoms become greatly reduced, putting them at significant risk of having severe episodes where they're dependent on others for help.

Let your diabetes care team know if you develop this problem as your treatment may need to be changed to reduce the risk.

Read more about how hypoglycaemia is treated.

Hypoglycaemia while sleeping

Having a hypo while you're asleep is known as nocturnal hypoglycaemia. It's more common in people who treat diabetes with insulin.

Although some people find their sleep is disturbed when they experience nocturnal hypoglycaemia, you may only notice the symptoms when you wake up in the morning.

The symptoms of nocturnal hypoglycaemia can include:

  • headache – often likened to having a hangover
  • feeling unusually tired in the morning
  • damp sheets or clothing from sweating

Page last reviewed: 21/05/2015

Next review due: 21/05/2017