What should you know about post exercise syncope?

Stopping vigorous activity removes the muscle pumping that helps return blood to the heart. Blood pressure may fall, particularly with heat, prolonged standing, dehydration or inadequate food. Other possibilities include anaemia, low blood sugar or an abnormal heart rhythm such as atrial fibrillation. Fainting during exertion, rather than after stopping, is more concerning and needs prompt medical review.

If warning symptoms begin, stop exercising, lie flat and raise your legs if safe; turn on your side if vomiting. Do not stand quickly or resume exercise that day. Once fully alert, take fluids and food if appropriate, and arrange medical assessment before returning to strenuous activity. Record the exercise, heat, meals, fluids, symptoms, duration of unconsciousness and injuries.

Call emergency services if fainting occurs during exercise, causes injury, lasts unusually long, or comes with chest pain, severe breathlessness, pounding heartbeat, seizure-like movements or confusion. Urgent assessment is also needed for repeated episodes, fainting without warning or a family history of sudden cardiac death. Never exercise alone until the cause has been assessed.

Ask whether your heart rhythm, blood pressure, blood count and glucose need checking, when exercise can restart, and which warning symptoms require emergency help. Bring a list of medicines and details from anyone who saw the episode.