What should you know about constant fainting?

Fainting is a brief loss of consciousness caused by reduced blood flow to the brain. It may follow prolonged standing, heat, pain, fear, dehydration, or a sudden drop in blood pressure. Anaemia can reduce oxygen delivery and cause tiredness, breathlessness, or paleness. Hypoglycaemia may cause sweating, shaking, hunger, confusion, or weakness before a blackout. Atrial fibrillation and other heart rhythm problems can cause palpitations, breathlessness, or fainting, sometimes without much warning.

The circumstances are crucial: what you were doing, your position, warning symptoms, injuries, recovery time, medication, and family history should all be recorded.

If you feel faint, lie flat and raise your legs if possible, or sit with your head lowered. Move away from heat and do not drive, climb, swim alone, or operate machinery until assessed. Once fully alert, take fluids if you can swallow safely. Arrange medical review after recurrent fainting, even if recovery was quick, and bring a witness account if available.

Call emergency services for fainting during exercise, chest pain, severe breathlessness, a racing or irregular heartbeat, seizure-like movements, serious injury, prolonged confusion, pregnancy, or no recovery. Urgent assessment is also needed when there was no warning, the episode happened while lying down, or several episodes occur close together.

Could my medicines, blood pressure, blood count, glucose, or heart rhythm explain this? Should I have an electrocardiogram or other checks? What activities should I avoid until the cause is clear?