Sudden blackout and fall: what should you know?

Fainting can happen after standing quickly, prolonged standing, heat, pain, fear, or not eating or drinking enough. Dehydration can reduce circulating fluid, while hypoglycaemia can affect brain function. Anaemia can reduce oxygen delivery and may cause tiredness or breathlessness. Atrial Fibrillation and other rhythm disturbances can reduce efficient heart pumping; palpitations before a blackout are useful information.

The fall itself matters. A head injury, broken bone, or wound may be present even when consciousness returns quickly. Someone who saw the event can help describe movement, skin colour, breathing, and recovery.

If the person is breathing, keep them lying flat and raise the legs if there is no serious injury. Loosen tight clothing, protect them from heat, and do not give food or drink until they are fully alert. Check for bleeding and avoid moving the neck after a hard fall. Record what happened before the blackout and how long recovery took, then arrange medical assessment.

Call emergency services for ongoing unconsciousness, difficulty breathing, chest pain, a severe headache, confusion, weakness on one side, repeated vomiting, seizure-like activity, a major head injury, or a blackout during exercise. Urgent assessment is also needed when the event occurs without warning, with palpitations, or while sitting or lying down.

Ask what may have triggered the event and whether you need an examination, blood tests, glucose testing, or heart monitoring. Mention recent illness, fluid loss, missed meals, new medicines, bleeding, palpitations, and any family history of sudden heart problems.