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A hypo is when your blood glucose level falls too low i.e. is less than 4 mmol/l. Early signs and symptoms of a hypo include:
  • shaking
  • sweating
  • intense hunger
  • poor concentration
  • paleness
  • headache
  • tingling lips or mouth
  • rapid heart beat
  • slurred speech
  • feeling irritable
  • mood changes
Later signs and symptoms include:
  • confusion
  • drowsiness
  • double vision
  • odd behaviour
  • speech difficulty
  • lack of co-ordination
  • coma

Hypo Unawareness

Sometimes people with diabetes lose their hypo warning signs, they become unable to notice when blood glucose is <4mmol/l. If this happens speak to your diabetic specialist nurse – s/he maybe able to help you regain these warning signs.

A hypo is most likely to occur if you:

  • eat less carbohydrate based food than usual for example bread, potatoes, pasta, rice, cereal
  • miss or delay a meal or snack
  • are more active than normal
  • take too much insulin or too large a dose of some diabetes tablets
  • take your insulin or diabetes tablets at the wrong time
  • take too much alcohol or take alcohol on an empty stomach-alcohol can cause hypos for up to 16 hours
  • are in a hot environment e.g on holiday or while in a hot bath

How to treat a hypo 

If you are conscious treat the hypo immediately and rest until symptoms resolve.

Step 1: Take 15 to 20g of fast acting carbohydrate i.e.:

  • 170 to 225ml Lucozade®
  • 225 to 300ml Lucozade® Sport
  • 150 to 200ml pure fruit juice
  •  150 to 200ml ordinary cola
  • 4 to 5 soft sweets e.g. wine gums, jelly babies
  • 5 to 6 glucose tablets e.g. Dextro energy®, Lucozade®
  • 4 to 5 Glucotabs®
  • 60ml bottle of Glucojuice®
  •  1½ to 2 tubes of glucose 40% gel (brands include Glucogel® and Rapilose®)

Foods containing fat, like milk or chocolate, are not recommended as they take longer to raise your blood glucose level.

Retest your blood sugar level.  If your blood glucose is still below 4mmol/L after 15 minutes take a further 15 to 20g of fast acting carbohydrate. If your blood sugar level is 4mmol/l or above go to step 2.

Step 2: Take 15 to 20g of slower acting carbohydrate, or your next meal or snack if due within 30 minutes.

Examples of 15-20g of slow acting carbohydrate include a slice of bread, 2 plain biscuits, a glass of milk and 1 biscuit or a yoghurt and a piece of fruit.

If you have a severe hypo and become unconscious you will need help from someone to treat the hypo.

An injection of the hormone glucagon can be given to raise blood glucose levels and restore consciousness. This is only if an injection is available and the person giving the injection knows how to use it. They should dial 999 to request an ambulance if:

  • a glucagon injection kit isn’t available
  • there’s nobody trained to give the injection
  • the injection is ineffective after 10 minutes

Make sure your family and friends are aware that they mustn’t give you anything by mouth if you are unconscious or unable to swallow. 


Blood Glucose and Driving:

  • If you inject insulin, check your blood glucose no longer than 2 hours before driving and then every 2 hours on long journeys. You may need to check your blood glucose if you take tablets that may cause hypos (sulfonylureas or glinides). Your doctor or nurse can give advice on how frequently to monitor. Group 2 drivers (bus/lorry) on a sulfonylurea or glinide are required by law to monitor their blood glucose level at least twice daily and at times relevant to driving.
  • If you have a hypo wait 45 minutes after your blood glucose level returns to normal (above 5mmol/L) before driving. DO NOT DRIVE IF BLOOD GLUCOSE IS LESS THAN 5MMOL/L
  • If you have a hypo when driving you must stop the vehicle as soon as it is safe to do so, remove keys from the ignition, move to the passenger seat (if possible) and treat the hypo.


  • Always carry fast acting carbohydrate. Keep hypo treatment beside the bed, in your car, handbag or jacket pocket for emergencies.
  • Take fast acting carbohydrate as soon as you feel a hypo beginning, or if your blood glucose level is less than 4mmol/L.
  • Tell relatives, friends and work-mates about hypos and how to treat them. Always carry identification that says you have diabetes.
  • If your food or activity level is going to be different from normal plan ahead.
  • Contact your nurse or doctor if you have regular or unexplained hypos or are losing your hypo symptoms.