Teenager fainting: what should you know?

Fainting, also called syncope, happens when the brain briefly receives less blood flow. Standing still for a long time, heat, fear, pain, skipping food, dehydration or suddenly standing can trigger it. Some teenagers feel warm, nauseated, sweaty, dizzy or see spots first. Anaemia or low blood sugar can contribute; an irregular heartbeat is less common but matters, particularly when fainting happens during exercise or without warning.

Lay the teenager flat and raise their legs if there is no injury. Loosen tight clothing, provide fresh air and check that they are breathing normally. Do not give food or drink until they are fully alert. After recovery, let them rest, sip water and eat if they missed a meal. Record what happened, including posture, activity, warning symptoms, duration and recovery. Arrange a clinical review after a first episode or repeated episodes.

Call emergency services if the teenager does not wake promptly, has trouble breathing, chest pain, a severe headache, a seizure, serious injury, confusion or weakness on one side. Seek urgent assessment for fainting during exercise, while sitting or lying down, after a racing or irregular heartbeat, or when there is a known heart condition or family history of sudden unexplained death. A clinician may assess blood pressure, heart rhythm and blood tests for causes such as Anaemia or Hypoglycaemia.

Ask whether the episode fits a simple faint, whether an ECG or blood tests are appropriate, and which activities should be paused while the cause is clarified. Mention medicines, supplements, eating and drinking patterns, menstrual bleeding, exercise symptoms and any family heart history.