What should you know about fainting vasovagal?

The nervous system can overreact to a trigger such as emotional distress, pain, heat, prolonged standing, or seeing blood. Blood flow to the brain briefly falls. Warning symptoms may include warmth, nausea, sweating, pale skin, dizziness, tunnel vision, or muffled hearing. Recovery often begins soon after lying down, but tiredness or mild nausea can linger.

A single episode may be harmless, but fainting can also follow dehydration, low blood sugar, anaemia, or a heart-rhythm problem. The symptom itself does not identify the cause. A clinician may ask what happened before, during, and after the episode and review medicines, medical history, and family history.

At the first warning, lie flat and raise your legs if possible. If you cannot lie down, sit and lower your head between your knees. Loosen tight clothing, move away from heat, and do not stand quickly. Someone who has fainted should be placed on their back with clear breathing; turn them onto their side if they are vomiting. Do not give food or drink until they are fully alert.

Call emergency services if the person does not wake promptly, has trouble breathing, chest pain, a severe headache, a seizure, serious injury, or new weakness or speech difficulty. Arrange medical review after a first unexplained episode, repeated fainting, fainting during exercise, or an episode without warning. Seek assessment when dehydration, anaemia, hypoglycaemia, or an irregular heartbeat may be involved.

Ask what trigger is most plausible, whether an examination or heart tracing is appropriate, how to prevent recurrence, and whether any medicine or activity needs adjustment. Keep a note of your position, symptoms, food and fluids, medicines, and recovery time.