Vagal fainting

Vagal fainting, also called reflex syncope, can follow prolonged standing, heat, pain, emotional shock, seeing blood, or straining. A reflex briefly slows the heart and widens blood vessels, so the brain receives less blood for a short period. Warning signs may include warmth, nausea, sweating, pale skin, blurred or narrowing vision, dizziness, and ringing in the ears. Recovery often begins after lying down, but the event still deserves review if it is new, repeated, unexplained, or associated with injury. Other conditions, including anaemia, dehydration, low blood sugar, or an abnormal heart rhythm, can also cause collapse and need consideration.

Lie flat promptly and raise your legs if possible. If lying down is unsafe, sit and lower your head between your knees. Loosen tight clothing, move away from heat, and ask someone to stay with you. Do not stand suddenly after the symptoms improve. Once fully alert, drink water if you can swallow safely and consider whether heat, missed food, illness, or prolonged standing was involved. Arrange a medical review after a first faint or any repeated episode so the history, medicines, pulse, blood pressure, and heart rhythm can be checked.

Call emergency services if the person does not wake promptly, has trouble breathing, chest pain, a severe headache, new weakness, an irregular pounding heartbeat, or a seizure-like episode. Urgent assessment is also needed after a serious injury, during exertion, while lying down, or when fainting occurs without warning. Do not give food or drink to someone who is unconscious. A faint with a slow recovery or repeated unexplained collapses should not be assumed to be vagal.

Tell the clinician what you were doing, the warning symptoms, how long recovery took, any injury, and whether relatives have had sudden heart problems. Ask whether you need an ECG, blood tests, medication review, or advice about driving and avoiding triggers.