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.
Important
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:
- immediately phone 111 for an ambulance, then
- give you an injection of glucagon.
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:
- pins and needles in your mouth and tongue
- sweating
- pale skin
- shaking hands or legs
- a headache
- blurred vision
- a fluttering heart (palpitations).
You may also feel:
- dizzy
- nervous
- sleepy
- hungry
- confused
- unable to concentrate.
You might have symptoms of a hypo when your blood glucose level isn't below 4 if:
- your blood glucose level is regularly high, and it quickly drops to normal
- you're anxious.
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:
- missing or delaying a meal
- not having enough starchy food (carbohydrates) with your meal or snack
- being more physically active than usual and not having extra food to fuel it
- having too much insulin or taking too many diabetes tablets
- drinking too much alcohol or drinking alcohol on an empty stomach
- allowing too much time between your injection and your meal
- changing the time when you have your insulin or tablets.
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.
If your blood glucose is less than 4, have one of the following options:
- three or four glucose tablets
- one tablespoon of glucose powder dissolved in water
- four to six large jelly beans
- one small glass (150 ml) of fruit juice
- one small glass (150 ml) of "ordinary" (non‑diet) soft drink
- one tablespoon of jam or sugar
- two sachets of Hypo-Fit gel (available from Diabetes Christchurch and some pharmacies).
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:
- a meal if it's due, or
- insulin just before or straight after your meal if it's due, or
- a snack such as:
- a sandwich made with one piece of bread, or
- a piece of fruit such as half a banana, or
- a glass of milk.
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.
SourcesReview key: HIDIA-21832
