What should you know about a syncope episode?

People may feel warm, nauseated, light-headed, sweaty, or develop blurred or narrowed vision before they lose consciousness. The person usually becomes responsive again after lying down, although tiredness or confusion can follow briefly. Triggers include standing still for a long time, heat, emotional distress, pain, dehydration, or missing food. Anaemia, low blood sugar, and heart-rhythm problems such as atrial fibrillation are among the health issues a clinician may consider. A faint does not by itself identify the cause, and many causes are treatable.

Help the person lie flat and raise the legs if there is no obvious injury or breathing problem. Loosen tight clothing, keep the area safe, and check that they are breathing normally. Do not give food or drink until they are fully alert. Once recovered, they should get up slowly and avoid driving, heights, hot environments, and swimming until the cause has been assessed. Arrange a clinical review, especially after a first episode or if fainting happens again. Note what the person was doing, any warning symptoms, medicines, injuries, and how quickly they recovered.

Call emergency services if the person is not breathing normally, does not wake promptly, has a severe injury, chest pain, marked breathlessness, a sudden severe headache, new weakness, trouble speaking, or a seizure-like episode. Urgent assessment is also needed when fainting occurs during exercise, while sitting or lying down, after a racing or irregular heartbeat, or repeatedly without warning. A clinician should assess any unexplained episode in a child, pregnant person, or someone with known heart disease.

Could my medicines, hydration, blood count, blood sugar, or heart rhythm have contributed? Do I need blood pressure checks lying and standing, an ECG, or other tests? What activities should I pause while the cause is being investigated?