Hypoglycaemia, commonly known as low blood sugar, is when the level of glucose in your blood drops too low. It’s sometimes known as a ‘hypo’.

By Wallace Health I Medically reviewed by Adrian Roberts.
Page last reviewed: October 2018 I Next review due: October 2021

What is hypoglycaemia?

Low blood sugar can affect anyone. However, it’s more likely if you have diabetes and are taking medicines such as insulin which lowers your blood sugar levels.

It can also affect you if you have another condition that lowers your blood sugar.

It’s important to recognise the signs of low blood sugar, so you can act quickly. It’s also a good idea to let your friends, family and colleagues know, so they can help you if it happens.

If it’s mild and you treat it quickly, it shouldn’t affect your long-term health. If it’s severe, and isn’t treated, it can sometimes be life-threatening.

How to tell if you have hypoglycaemia

Low blood sugar symptoms include:

  • Feeling very tired, shaky and anxious
  • Your skin may be paler than usual
  • Lips may feel tingly
  • Sweating
  • Irritability
  • Feeling hungry
  • Fast heartbeat (palpitations)

If your blood sugar levels fall very low, you may also experience:

Talk to your doctor if you’re concerned about symptoms

You can book an appointment with a Spire private GP today.

Diagnosis and tests for hypoglycaemia

Your GP will talk to you about your symptoms.

If you’ve already been diagnosed with diabetes, they’ll tell you if your medication needs to change or be adjusted.

If you don’t know why your blood sugar levels have been affected, they may carry out some blood tests for diabetes or other medical problems.

Causes of hypoglycaemia

Low blood sugar can be a sign of diabetes or another medical condition that lowers glucose in your blood.

If you’ve already been diagnosed with diabetes, it can be caused by:

  • Too much insulin or other medicine lowering your blood sugar levels
  • Skipping meals
  • Exercise – so it’s important to carry some fast-acting carbohydrates (eg glucose tablets)
  • Alcohol can affect your blood sugar levels, especially if you’re taking insulin

If you don’t have diabetes, common causes of low blood sugar are:

  • Drinking too much alcohol without food
  • Not eating enough or dieting
  • Eating too much carbohydrate

Less common causes are:

  • Certain medications including quinine (for malaria)
  • Weight loss surgery
  • It can be an early sign of type 1 diabetes

Low blood sugar can also be a symptom of other medical conditions, including hormone disorders and liver and kidney problems.

Common treatments for hypoglycaemia

Treatments for low blood sugar will depend on your symptoms.

You can often treat low blood sugar by immediately having a high-sugar snack or drink, or by taking medication prescribed by your GP. You may not need any more treatment.

If it’s severe, you may need emergency treatment in hospital.