How common is fainting in anaemia?

Anaemia means there are fewer healthy red blood cells available to carry oxygen around the body. Some people notice tiredness, breathlessness on exertion, palpitations, headache or dizziness before a faint. Fainting has many possible causes, including heart rhythm changes, dehydration and low blood pressure. A blackout therefore needs assessment rather than being attributed to anaemia without checking.

If you feel faint, sit or lie down safely and raise your legs if possible. Do not drive, climb, swim alone or use machinery until you have been assessed. Arrange prompt medical advice after a first faint or a new episode. A clinician may ask about bleeding, diet, medicines, heavy periods, recent illness and what happened immediately before the event.

Call emergency services if fainting occurs with chest pain, shortness of breath, a fast or irregular heartbeat, severe headache, seizure-like movements, serious injury, pregnancy, or difficulty waking. Urgent assessment is also needed if black stools, vomiting blood or heavy bleeding is present. These features can signal a cause requiring immediate treatment.

Ask what may be causing the anaemia, whether blood tests or other checks are needed, and whether your symptoms could have another explanation. Ask when it is safe to return to driving, work or exercise after a faint.