Hypoglycaemia means low glucose in the blood. It occurs when the blood glucose level (BGL) falls below 4mmol/L. In people with diabetes, hypoglycaemia is a side effect of insulin and some oral medications known as sulphonylureas.

Hypoglycaemia can make it hard to concentrate and carry out everyday activities. Some activities, such as driving and operating machinery, are not safe if BGLs are less than 5.0mmol/L.
Planning is important in preventing hypos. Understanding what causes a hypo can help you avoid having low BGLs.

What are the main causes of hypoglycaemia?

For those on insulin or sulphonylureas, a hypo can be caused by one or a number of events including:

  • Delaying or missing a meal
  • Mismatch of carbohydrate with medication
  • Unplanned physical activity*
  • More strenuous exercise than usual*
  • Too much insulin or oral medication
  • Drinking alcohol
  • Stress and anxiety

Note: *Hypoglycaemia may be delayed for up to 12 hours after exercise

If you are doing more activity or likely to eat on the run, plan well ahead and always carry a “Hypo Kit” (see below). Discuss exercise management with your health care team.

Please note that other diabetes medications (please refer to medication for type 2 diabetes ) on their own do not generally cause hypoglycaemia, however hypoglycaemia may occur when they are used in conjunction with sulphonylureas.

These include:

Chemical nameBrand name
GliclazideDiamicron, Glyade,Diamicron MR,Nidem
GlbenclamidieDaonil, Semi Daonil,Glimel
GlipizideMelizide, Minidiab
GlimepirideAmaryl, Dimirel

Please note that other diabetes medications (please refer to medication for type 2 diabetes) on their own do not generally cause hypoglycaemia, however hypoglycaemia may occur when they are used in conjunction with sulphonylureas.

What are the symptoms of hypoglycaemia?

The signs and symptoms of hypoglycaemia can vary from person to person, and may progress to more serious signs and symptoms if the BGL continues to drop. Early signs and symptoms of hypoglycaemia can include:

  • weakness
  • trembling
  • sweating
  • paleness
  • hunger
  • nausea
  • light headedness
  • headache
  • mood change

Later signs and symptoms of hypoglycaemia can include:

  • lack of coordination
  • not able to help oneself
  • disorientated, unaware or seeming drunk
  • not able  to drink or swallow
  • not able to stand
  • not able to follow directions
  • loss of consciousness
  • seizures

Hypoglycaemia can be classified as:

  • mild where the person is able to treat their own hypo; or
  • severe where the person needs assistance from another person.

It is important that a mild hypo is treated as quickly as possible and appropriately to stop the BGL from dropping lower, which could lead to a severe hypo.

What should be done if you feel symptoms of hypoglycaemia?

Check your BGL, if you are able to. If you are unable to, treat as a hypo just to be sure.

How is hypoglycaemia treated?

If your BGL is below 4.0mmol/L OR you cannot check your BGL and you suspect you are having a hypo:

  1. Take 15-20g of fast acting carbohydrate such as: 6-7 jelly beans OR 150ml soft drink (not diet/ sugar free) OR 3 teaspoons sugar or honey OR 150ml fruit juice 3 glucose tablets (5g each) OR
  2. After 15 minutes, re-check your BGL to confirm the BGL has increased above 4.0mmo/L. If unable to re-check BGL, assess if symptoms have subsided.
  3. If you are no longer having (BGL >4.0mmol/L), or suspect you are having, a hypo, and your next meal is more than 20 minutes away, it is recommended you eat a “follow up” food of longer acting carbohydrate such as:
  • One slice of bread or
  • One glass of milk or
  • One piece of fruit or
  • Two to three pieces of dried apricots, figs or other dried fruit or
  • One tub natural low fat yoghurt or
  • Six small dry biscuits and cheese.

This will help to keep BGLs above 4.0mmol/L and prevent another hypo.

4. If your BGL remains below 4.0mmol/l, or still feel symptoms of a hypo, repeat procedure from Step 1.

What should I include in my hypo kit?

If you are at risk of a hypo it is advisable to be prepared and always carry a “hypo kit.” A hypo kit only needs to contain a few essentials:

  • Monitoring equipment (blood glucose meter, glucose strips and finger pricker)
  • 2 or 3 quick acting hypo treatments (e.g. 6-7 jelly beans; a can of soft drink)
  • Some follow up, longer acting carbohydrates such as a sandwich or a tub of yoghurt

What happens if hypoglycaemia is not treated?

If not treated straight away, your BGL can continue to drop which may lead to:

  • Loss of coordination
  • Confusion
  • Slurred speech
  • Loss of consciousness/ fitting

What should be done if the person with diabetes is unconscious, drowsy or unable to swallow?

This is a diabetic emergency, and assistance and treatment must be provided:

  1. Never give food or drink by mouth
  2. Place person on their side and make sure airway is clear
  3. Give an injection of glucagon if available and you are trained to give it (see below)
  4. Phone for an ambulance (Dial 000) and state that the person is unconscious and unwell AND the person has diabetes and is having a hypo.
  5. Wait with the person until help arrives


Glucagon is a hormone which raises the blood glucose level. It is injected into the muscle such as the backside or thigh, and is used to reverse severe hypoglycaemia in the person with diabetes (If the person cannot swallow, is unconscious or fitting).

Glucagon stimulates the release of glucose from the liver and usually raises the blood glucose level 10 minutes after injecting, and lasts for approximately half an hour.
Glucagon needs to be injected by someone other than the person with diabetes, which means family members and or friends should be trained in how to use it.
People with diabetes using insulin or blood glucose lowering medications should discuss glucagon use with their doctor.
Glucagon is only available on prescription from your doctor.

Alcohol and hypoglycaemia

Alcohol can cause glucose levels to LOWER if you are taking insulin or sulphonylureas so alcohol can increase your risk of hypos. Other risks include:

  • When you are drinking alcohol, you may not recognise the signs and symptoms of a hypo;
  • You may not react as quickly to treat a hypo
  • People may assume you are drunk and not help
  • The hypo may be more difficult to treat

If you decide to drink alcohol it is important to make sure you are eating enough carbohydrate foods. You can also discuss any questions you have with your doctor and diabetes educator. You can learn more about alcohol and diabetes here.

What is Impaired Awareness of Hypoglycaemia (IAH)?

Impaired Awareness of Hypoglycaemia (IAH) occurs when people do not feel the early warning symptoms of hypoglycaemia or only experience symptoms when their blood glucose levels drop very low.  If you have hypos often or have had diabetes for many years your risk of not sensing your hypos is higher.
IAH can be dangerous. When BGLs fall below 2.8mmol/L, brain function slows down, causing reduced concentration and response time, confusion, poor coordination, blurred vision, and can lead to unconsciousness.

If unable to detect hypos until this late stage, accidents, falls and injury can occur. You may be unable to treat the hypo yourself, and may need help from others.

IAH is common in people with type 1 diabetes – as many as a quarter of all people with type 1 diabetes are unaware of their hypos.

You may have IAH if:

  • Your BGL is less than 4.0mmol/L before meals or on waking
  • Your BGL is less than 3.5 mmol/L and you still feel OK
  • You have recently experienced severe hypoglycaemia (seizure or loss of concentration) without warning signs.
  • You notice that you don’t sense your hypos until blood glucose levels are less than 3.0mmol/L .
  • Your HbA1c is 6% (42mmol/mol) or less.

You are more likely to have IAH when

  • You have had a hypo overnight, or in the previous 24-48 hours
  • You have repeated hypos
  • You have drunk alcohol in the last 12 hours
  • You take beta blockers (a blood pressure medication), steroid medication or sleeping tablets
  • You have had insulin treated diabetes for many years

If you have impaired awareness of hypoglycaemia you need to:

  • Check your BGL more often.
  • Check with your doctor if you are medically fit to drive
  • Carry glucose with you at all times.
  • Let others know what to look for, how to treat your hypos, and where you keep your glucose.
  • Have a glucagon kit with you and make sure a family member is trained in how to use it.

If you think you could have IAH it is important you discuss this with your doctor or diabetes educator as soon as possible. Blood glucose targets need to be raised for several weeks for symptoms of hypo to be regained. IAH is more common in people with type 1 diabetes but people with type 2 diabetes can also have IAH. However, it is less common and generally occurs in people who are on insulin and/ or who have had diabetes for a long time.

To learn more about self managing type 1 diabetes, read about the DAFNE program (Dose Adjustment for Normal Eating)

What else should I know about?

  • Always carry hypo treatment with you if you are taking insulin or medications that lower your blood glucose level
  • Wear identification that says you have diabetes
  • If you are participating in physical activity/sport, monitor your blood glucose level before commencing, and during, activity.You may also need to eat extra carbohydrate to maintain a safe blood glucose level.
  • If you are driving and develop signs of hypo, pull over to the side of road and treat the hypo
  • Wait at least 30 minutes after your blood glucose reads above 5.0 mmol/L before you start driving again.
  • You should always check your blood glucose level before driving and REMEMBER your blood glucose level must be above 5.0mmol/L to drive.
  • If you have an episode of severe hypoglycaemia involving loss of consciousness, you should not start driving again until you have checked with your doctor.
  • Make sure that your family, friends, school staff, co-workers and carers know how to treat and recognise hypoglycaemia.
  • If taking Acarbose (Glucobay), carry pure glucose with you such as glucose tablets, glucose gel or Lucozade.
  • Acarbose will delay the absorption of all other types of carbohydrate foods.
  • Make sure you eat carbohydrates if drinking alcohol.

This article was originally published by Diabetes Victoria at www.diabetesvic.org.au