Hypoglycaemia is a blood glucose level below normal – that is, less than 3.5mmol/L. If there is too much insulin for the amount of glucose in your blood stream, hypoglycaemia will occur.
Hypoglycaemia (hypo) can occur in someone who is treated with insulin and/or sulphonylurea tablets. It does not occur when treatment is by diet alone or with other diabetes tablets.
What happens with low blood glucose?
Hypoglycaemia can be serious because the brain needs constant glucose; so a person with low blood glucose can pass out, if their hypoglycaemia is not detected and treated early.
Situations that can lead to hypoglycaemia include:
- missed or late meals or snacks
- extra physical activity without extra food or reduced insulin dose or tablets
- too much alcohol or drinking alcohol on an empty stomach
- too high a dose of insulin or tablets for diabetes.
How do you know when your blood glucose level is low?
You may experience some of the early warning signs:
- sweating
- shaking
- feeling dizzy
- hunger
- palpitations (rapid heart beat)
- tingling or numbness around the mouth
Signs of very low blood glucose are:
- headache
- double vision
- unusual behaviour
- confusion
- poor co-ordination
- Drowsiness (feeling very sleepy) which may lead to unconsciousness
Don’t wait, treat your hypo quickly because it can get worse and you could pass out.
Hypoglycaemia makes it hard to concentrate and do normal activities, so driving and operating machinery are not safe if blood glucose levels are less than 3.5mmol/L.
Hypoglycaemia Unawareness
Some people do not feel any different when their blood glucose levels are low, or only become aware when they have become dangerously low. This is called hypoglycaemia unawareness. It is more likely in people who have frequent hypoglycaemia or who have had diabetes for a long time, but is more often seen in type 1 diabetes. It can be dangerous, as you could pass out without warning. If you have hypoglycaemia unawareness, you will need to rely on your blood glucose monitor more often, eg before
activities such as driving.
You should treat blood glucose levels under 3.5mmol/L, even if you have no symptoms!
Try not to over treat your hypo, as this may cause high blood glucose levels. Treating it quickly with fast acting glucose is better than slow acting sugars such as chocolate or juice. This may help stop the strong hunger that some people feel when having a hypo, which leads to eating too much.
What you should do if your blood glucose is too low.
- Eat or drink something containing quick acting glucose immediately, such as:
- 100ml of Lucozade or
- 5 jelly beans or 3 glucose tablets or
- 150ml of ordinary lemonade
- Check your blood glucose level in 5–10 minutes and if still low, repeat glucose
- When your blood glucose level has returned to normal, eat your regular meal or snack keep your level up
- Try to work out what caused your hypo so you can stop it from happening again.
Prevent hypoglycemia
- Do not skip meals and snacks
- Talk to your doctor if you don’t know why you had a hypo as you may need less insulin or diabetes tablets
- Do not drink alcohol without eating some carbohydrate food. Avoid drinking too much alcohol.
If you take insulin:
- Take less insulin before playing sport, exercising hard or for longer than 30 minutes.
- Take less of your long acting bedtime insulin if you exercise for long periods or in the late afternoon or evening
- Eat extra carbohydrate to balance extra physical activity
- Always carry glucose lollies or drink with you, just in case
- Check your blood glucose levels regularly
- Speak to your doctor about reducing your insulin dose if BG levels are <4mmol/L.
Contact your doctor if
- Your blood glucose levels fall below 3.5 mmol/L
- You may need to take less insulin or diabetes tablets.
If you pass out, people should:
- not give you food or drink, as you may choke
- call 000 for an ambulance immediately
- roll you onto your left side
- not give you insulin
- inject glucagon, if they know how to do so.