Hypoglycaemia means an abnormally low level of sugar (glucose) in the blood. When your glucose level is too low, your body does not have enough energy to carry out its activities. This is described as a 'hypo'.
Hypoglycaemia is most commonly associated with diabetes, and mainly occurs if someone with diabetes takes too much insulin, misses a meal, or exercises too hard. Some diabetes treatments, such as certain tablets, can also cause hypoglycaemia.
People who do not have diabetes can also experience hypoglycaemia, although this is much rarer. It can be triggered by malnutrition, binge drinking or certain conditions, such as Addison’s disease.
Read more about the causes of hypoglycaemia.
What are the symptoms of hypoglycaemia?
Most people will have some warning that their blood glucose levels are too low, which will give them time to correct them. Symptoms usually occur when blood sugar levels drop under 4 millimoles per litre (mmol).
Typical early warning signs are feeling hungry, trembling or shakiness and sweating. In more severe cases there can also be confusion and difficulty concentrating.
It is also possible for hypoglycaemia to occur during sleep, which can cause excess sweating, disturbed sleep and feeling tired and confused upon waking.
Read more about the symptoms of hypoglycaemia.
Correcting hypoglycaemia
The immediate treatment for a hypo is to have some food or drink that contains sugar (such as chocolate, sugar cubes or fruit juice) to end the attack. After having something sugary, you may need to have a longer-acting carbohydrate food, such as a few biscuits or a sandwich, depending on which insulin you are using.
A hypo is often confused with having too much sugar in the blood, which is called hyperglycaemia. If you are not sure whether someone has hypoglycaemia or hyperglycaemia, always give them food containing sugar, such as a chocolate bar or a glass of fruit juice. As long as they are fully conscious, it will do them no harm.
If hypoglycaemia is not treated, it may lead to unconsciousness because there is not enough glucose for normal brain function. At this stage, an injection of the hormone glucagon can be given to quickly raise blood glucose levels and restore consciousness.
Read more about how hypoglycaemia is treated.
Preventing a hypo
If you have diabetes, the safest way of avoiding a hypo is to keep a regular check on your blood sugar and know how to recognise the early symptoms. Make sure you eat regularly and limit your alcohol intake. It is also important to eat some form of carbohydrate before exercising.
Always carry with you dextrose tablets, a carton of fruit juice (one that contains sugar), or a chocolate bar in case you feel symptoms coming on or you detect a low level on your glucose-testing meter.
Make sure your friends and family know about your diabetes and the risk of hypoglycaemia. It may also help to carry some form of identification that lets people know about your condition in an emergency.
When hypoglycaemia occurs due to an underlying condition other than diabetes, the condition will also need to be treated to prevent a further hypo.
Read more about how to prevent hypoglycaemia.
