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Guide to Diabetes

What is Hypoglycaemia or "a Hypo"?

If you have diabetes, your blood glucose levels can be erratic, sometimes becoming very low – this is called hypoglycaemia (or a “hypo”), and can happen when your blood glucose levels drop below 
4 mmol/l.


A number of situations can cause a hypo:

  • Too much insulin or too many diabetes tablets

  • Delayed or missed meals or fasting

  • Eating less starchy foods than usual

  • Unplanned or strenuous activity

  • Drinking too much alcohol or drinking alcohol without food

Sometimes there is no obvious cause, but treatment should always be carried out immediately, as advised.

Early signs and symptoms of a hypo include:

  • Sweating heavily

  • Feeling anxious

  • Trembling and shaking

  • Tingling of the lips

  • Hunger

  • Going pale

  • Palpitations

Symptoms may vary from person to person, but you will feel “different” very quickly. 

If you miss these early signs, the symptoms may get worse and include:

  • Slurring your words

  • Behaving oddly

  • Being unusually aggressive or tearful

  • Having difficulty in concentrating

If you do not treat your hypo at this stage, you may become unconsciousness.

How to treat a hypo

If you recognise that you are having a hypo, you should treat it immediately with something that will raise your blood glucose quickly. Suitable treatments are:

  • 100ml- 120ml of Lucozade™, OR
  • 150ml -200ml (a small can) of non-diet fizzy drink, although amounts may vary, OR
  • 150ml- 200 ml (a small carton) of smooth orange juice, OR
  • 4–5 GlucoTabs®, 5–6 dextrose tablets,
  • or 4 Jelly Babies.

If you do not feel better or your blood glucose level is still less than 4 mmol/L after 5–10 minutes, repeat ONE of these treatments.
If you are no better after 3 treatments SEEK ADVICE.

When you start to feel better, and if you are not due to eat a meal, eat some starchy food, like a sandwich or banana. 

If you are not able to treat your hypo yourself, but are still conscious and able to swallow, someone can give you glucose gel if you have this available.

If you become unconscious, you will need immediate emergency treatment. Someone should dial 999 for an ambulance. You should be put on your side with your head tilted back. (recovery position) Glucose treatments should NOT be put in your mouth

How to avoid hypos

  • Eat regularly
  • You may need to eat more carbohydrate before and after physical activity
  • Keep to sensible alcohol limits and do not drink on an empty stomach
  • Take your medication at the recommended dose and times
  • If you are testing your blood glucose levels, and notice your readings are regularly dropping, discuss this with your diabetes team as you may need a change in medication or your insulin regimen adjusted
  • Always carry glucose with you to treat hypos quickly

Driving and Hypos

  • Keep glucose treatments in the car at all times
  • Check your blood glucose before driving
  • Do not drive if your blood glucose level is less than 5 mmol/L
  • If you have a hypo while driving, stop the car as soon as possible. Remove the keys to demonstrate you are not in charge of the car and move into the passenger seat if safe to do so. Treat the hypo as advised. You should not drive for at least 45 minutes after recovery because your response rates will be slower

What you should if you think you are having a hypo

  • Having a hypo means that your blood glucose level is too low
  • Act IMMEDIATELY by eating or drinking something that will raise your blood glucose quickly
  • Never ignore the warning signs
  • Make sure other people know what to do when you are having a hypo
  • Always carry glucose and diabetes identification

Consequences of frequent hypos

  • You may not recognise future hypos
  • Fear and anxiety of getting further hypos
  • Effects on employment and driving


ICDS - All you need to know about Hypos (PDF 195KB)

Patient information leaflet produced by the diabetes team UHL for patients and Healthcare Professionals. Download Document