Blood sugar levels Dr Rob Hicks If blood sugar levels fall or rise abnormally in someone with diabetes, they'll experience a variety of symptoms.

In this article

Hypoglycaemia

Hyperglycaemia

A 'hypo' is when the blood sugar levels fall below normal. It's short for hypoglycaemia, which means low blood sugar.

A hypo may occur:

• after an insulin injection
• after taking oral diabetes medication
• if a meal is missed or delayed
• after strenuous exercise
• if alcohol is drunk on an empty stomach

The symptoms of a hypo vary from person to person. Mild hypo may cause:

• weakness
• dizziness
• sweating
• hunger
• shaking
• irritability
• mood swings

A mild hypo can usually be treated with some form of sugar. Types of sugar to use during mild 'hypo':

• dextrose tablets (carry these if you have diabetes)
• three sugar lumps
• two teaspoons of sugar
• chocolate or sweet biscuits
• a sweet drink

When the blood glucose level falls even lower, then the person may behave strangely and become confused (often mistakenly interpreted as drunkenness). Under these circumstances it may be easier and quicker to give sugar in liquid form, such as a sweet drink.

In severe hypoglycaemia, the person loses consciousness. Under these circumstances an injection of glucagon is given, which temporarily raises the level of blood glucose. Once the person is conscious they can be given some sugar and a snack to prevent the hypo from recurring.

Always have sugar tablets or another form of sugar available

People with diabetes and those close to them are taught to look out for signs that their sugar level may be low, and are advised to always have sugar tablets or another form of sugar available to raise the level quickly. This solves the problem quickly and prevents serious consequences.

People with diabetes are advised to carry some form of identification saying that they have diabetes, so that people will realise their condition should they get into difficulty and need help.

Hyperglycaemia is when the blood glucose level is too high. When it's mildly raised then symptoms of uncontrolled diabetes occur, namely excessive thirst, passing urine frequently, tiredness, weakness and lethargy.

If the blood glucose level becomes dangerously high then the person becomes dehydrated and may become comatose. This is a medical emergency that requires hospital treatment.

This article was last medically reviewed by Dr Roger Henderson in January 2009.
First published in April 2001.