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HealthInfo Canterbury

Low blood glucose (hypoglycaemia)

Huka ā-toto hakahaka

Hypoglycaemia, also called a hypo, means you have a low blood glucose (sugar) level. Any blood glucose level less than 4 is low.

It happens mainly if you inject insulin, but it can also happen with some tablets.


A hypo can happen quickly, and you need to treat it immediately. If you don't treat your hypo, you can become unconscious.

Test your blood glucose level then follow the self-care advice below.

Tell your whānau (family) and friends how to treat a hypo so they can help you if you can't help yourself. If you're unconscious, they should:

Symptoms of a hypo

You can get hypoglycaemia if you haven't eaten for a long time, have given yourself too much insulin or exercised hard without having any extra food.

If you're having a hypo, you're likely to have some or all of the following symptoms:

hypo signs

You may also feel:

You might have symptoms of a hypo when your blood glucose level isn't below 4 if:

Reducing your risk of a hypo

You can reduce your risk of having a hypo if you avoid the things that can cause hypos. These include:

You should always carry a hypo treatment with you. If you don't treat a hypo, you may lose consciousness or have a fit or seizure. This is rare and usually only if you have Type 1 diabetes, but it's important to treat all episodes of hypoglycaemia correctly.

Self-care for a hypo

If you think there's a danger you might be having a hypo, even without symptoms, test your blood glucose level.

jellybeansIf your blood glucose is less than 4, have one of the following options:

Wait 15 minutes then test your blood glucose again. If your blood glucose is still below 4, have a repeat helping from the above list.

Once your blood glucose is above 4, have:

Don't drive when you're having a hypo as you risk having an accident or losing your licence.

Tell your general practice team or diabetes nurse if you keep having hypos.

On the next page: Guidelines for giving glucagon

Written by Christchurch Diabetes Centre. Adapted by HealthInfo clinical advisers. Last reviewed November 2022.


Page reference: 178645

Review key: HIDIA-21832