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Low blood sugar (hypoglycaemia)

Hypoglycaemia or a "hypo" happens if the level of sugar in your blood is too low and makes you ill. Find out how a hypo can make you feel and how to stop them.

Low blood sugar (glucose) mainly affects people with diabetes, especially if they’re on insulin or a sulphonylurea. You can usually treat a hypo yourself – but do it quickly because it can be dangerous to ignore it.

Signs of low blood sugar: don’t ignore

Not everyone feels the same if they have a low blood sugar: different people have different symptoms, which can also change over time. But some common early signs of a low blood sugar include:

  • feeling hungry
  • sweating
  • tingling lips
  • feeling shaky or trembling
  • dizziness or a fast heartbeat (palpitations)
  • feeling tired
  • becoming annoyed or upset easily
  • turning pale

Treat low blood sugar to avoid a hypo

If you have a device to check your blood sugar level, a reading of less than 4mmol/L is too low, so treat it.

If you don’t treat your low blood sugar, you may start to:

  • feel weak or sleepy
  • have blurred vision or find it hard to focus
  • have slurred speech or feel really clumsy (like being drunk)
  • have seizures (fits) or even collapse or pass out

A hypo can also occur when you’re sleeping, and it may wake you up during the night, or cause damp sheets (from sweating), headaches and tiredness when you do wake up.

Treating low blood sugar or a hypo

You can treat low blood sugar or a hypo yourself (if less than 4mmol/L) by having a sugary drink (fruit juice) or a snack (a few sweets or dextrose tablets). Examples of portions containing 15-20gs of quick-acting carbohydrate needed to treat a hypo are:

165mls of apple juice or 250mls of orange juice or 8 jelly bean sweets or 6 fizzy cola bottle sweets

Test your blood sugar

Test your blood sugar after 10-15 minutes and if it's still below 4mmol, have another sugary drink or snack and wait another 10-15 minutes before taking a second reading.

If your test shows your sugars are 4mmol or above, eat your main meal and include some  carbohydrate (pasta, bread) or eat a carb-based snack like a couple of biscuits or a glass of milk.

A hypo doesn’t mean a trip to the GP

If you have more than two hypos in a week, contact your healthcare team.

Struggling to recognise your hypo's?

After taking this course 88% of people were able to spot a hypo, 89% knew how to treat a hypo and 63% had fewer severe hypos at 6 months!