Why does hypoglycaemia cause fainting?

Falling glucose can first cause sweating, tremor, hunger, unusual behaviour, blurred thinking, or weakness. If it continues untreated, a person may become confused, unable to cooperate with treatment, unconscious, or have a seizure. Fainting is a common presentation of Hypoglycaemia, but a blackout has other possible causes and should be taken seriously.

A brief loss of consciousness can result in a head injury or other harm, especially if it happens while standing, driving, swimming, or using equipment. Anyone who has fainted needs a careful account of what happened before and after the event.

Treat a person who is unconscious, having a seizure, or unable to swallow as an emergency. Call emergency services, place them on their side if possible, and follow their prescribed glucagon rescue plan if one is available and you know how to use it. Do not put food, drink, or tablets in their mouth.

If the person is awake and can swallow safely, they can follow their own fast-acting carbohydrate plan. They should not resume driving or hazardous activity until they have recovered and have advice appropriate to their situation.

Emergency care is needed after a fainting episode linked to suspected low glucose, particularly if recovery is delayed or an injury occurred. Seek prompt review after any severe episode, recurring lows, overnight symptoms, or difficulty recognising warning signs. A clinician can review food intake, activity, illness, alcohol, and glucose-lowering medicines.

Ask whether you should have glucagon available, who should be taught to use it, and which circumstances mean you need emergency help. Discuss practical prevention around meals, exercise, fasting, and sick days.