The symptoms of hypoglycaemia usually begin when a person's blood glucose level drops below 4 millimoles per litre (mmol).
Most people will experience some early warning symptoms, although some people with diabetes can experience sudden or severe hypoglycaemia.
The symptoms may vary from person to person and it is important to be aware of the early warning signs so that you can treat them. Read more about how hypoglycaemia is treated.
Early signs
The early warning signs of mild hypoglycaemia may include:
- feeling hungry
- sweating
- dizziness
- tiredness (fatigue)
- blurred vision
- trembling or shakiness
- anxiety or irritability
- going pale
- fast pulse or palpitations
- tingling of the lips
Signs of more severe hypoglycaemia include:
- difficulty concentrating
- confusion
- disorderly or irrational behaviour, which may be mistaken for drunkenness
Nocturnal hypoglycaemia
Having a hypo while you’re asleep is known as nocturnal hypoglycaemia and is more common in people who treat diabetes with insulin. You will often only notice the symptoms when you wake up in the morning. The symptoms can include:
- headache
- disturbed sleep
- feeling unusually tired in the morning
- damp sheets or clothing from sweating
