Diabetes and Hypoglycemia

Hypoglycemia is defined as blood glucose levels dropping under 4 mmol/L
Hypoglycemia is defined as blood glucose levels dropping under 4 mmol/L

Hypoglycemia occurs when blood glucose levels fall below 4 mmol/L. Knowing the symptoms and causes of hypoglycemia can help you avoid a hypo.

What is hypoglycemia?

Hypoglycemia occurs when the level of glucose present in the blood falls below a set point:

  • Below 4 mmol/L (millimoles per litre)

Being aware of the early signs of hypoglycemia will allow you to treat your low blood glucose levels quickly - in order to bring them back into the normal range.

It is also recommended to make close friends and family aware of the signs of hypoglycemia in case you fail to recognise the symptoms.

What are the symptoms of hypoglycemia?

The main symptoms associated with hypoglycemia are:

Symptoms of hypoglycemia can also include:

What are the causes of hypoglycemia?

Hypoglycemia is caused by a variety of different factors, all of which diabetics need to be aware of.


Hypoglycemia is when blood glucose levels fall below 4 mmol/L. Hypoglycemia in relation to diabetes is often abbreviated and referred to as a hypo. Hypos are more likely to occur for people taking insulin or a type of tablets called sulfonylureas.

If you’re on medication that can cause hypos, it’s important to be aware of the signs of hypoglycemia, which include:

  • feeling tired or weak
  • being hungry
  • becoming pale
  • sweating
  • becoming anxious or irritable
  • a tingling sensation in tongue or lips
  • trembling or shakiness

In more severe cases of hypoglycemia, someone with diabetes may experience:

  • confusion
  • convulsions
  • loss of consciousness

The NHS lists the following as reasons why hypos may occur:

  • If you have too much diabetes medication for the amount of carbohydrate you’ve had
  • If you miss a meal
  • If you take more exercise than normal
  • If you drink alcohol on an empty stomach

It is advisable to treat a hypo as soon as you recognise the symptoms.

Diabetes UK recommend that you treat a hypo by taking 15-20g of a short-acting carbohydrate.
Having 3 or more glucose tablets will raise your blood sugar the quickest. If glucose tablets are not available, other options can include:

  • 250ml of a non-diet soft drink
  • 250ml of fruit juice
  • Five sweets such as jelly babies

If your next meal is not due, follow the short acting carbohydrate with some longer acting carbs such as a slice or bread or a portion of fruit. It is recommended to re-test your blood sugar after 15 to 20 minutes and re-treat if your sugar levels are still less than 4 mmol/L.

If someone experiencing hypoglycemia is unconscious, the NHS advises that they are put into the recovery position and either given glucagon or an ambulance called. If no-one has been trained to give glucagon, an ambulance should be called.

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How serious is hypoglycemia?

Hypoglycemic episodes can range from mild to severe. Mild hypoglycemia is generally able to be treated by the individual.

However, severe hypoglycemia will need aid from a family member or doctor.

What are the health impacts of hypoglycemia?

Hypoglycemia, as well as being frightening for yourself and those around, can lead to the following:

Do symptoms always occur before hypoglycemia?

Most people experience some warnings before the onset of hypoglycemia. However, some diabetics may experience little or no warning before the onset of sudden or severe hypoglycemia.

What is the best way to avoid hypoglycemia?

To avoid hypoglycemia, diabetes experts advise diabetics to keep a constant level of glucose in the blood. Testing blood sugar levels regularly to make sure they are not rising or falling below the optimum level.

How is hypoglycemia diagnosed?

A diagnosis of hypoglycemia is made by measuring blood sugar levels with a glucose meter. Any blood glucose level below 4.0 mmol/L indicates that the individual has hypoglycemia.

NB: Urine tests do not detect hypoglycemia.

How do I treat hypoglycemia?

A mild case of hypoglycemia can be treated through eating or drinking approximately 10-20g of sugar (i.e. carbohydrates). Some diabetics carry glucose tablets for this express purpose.

Serious hypoglycemia will require medical attention. In this instance, paramedics will use glucagon or provide glucose intravenously. Some diabetics have glucagons injections at home, in the form of glucagons kits.

This allows immediate treatment and the possibility of avoiding hospital. For those diabetics that experience regular hypoglycemia, blood sugar levels should be tested regularly.

How can I avoid and be prepared for hypoglycemia?

Knowing and being aware of the symptoms of hypoglycemia allow diabetics to get treatment quickly. Experts advise diabetics to always carry sugar (glucose tablets are effective). Measuring blood glucose levels regularly, and in accordance with one’s lifestyle, is also recommended.

Eating regularly and being aware of how food affects your blood sugar levels allows, as does taking care when doing exercise.

Are hypos catching you without warning? Join the Hypo Awareness Program for a comprehensive guide towards recovering your hypo awareness »