Heart palpitations in teenagers: possible causes

Rapid growth, heavy periods, poor food intake or illness can contribute to anaemia or iron deficiency, which may be accompanied by a racing heartbeat and tiredness. Dehydration after sport, vomiting, diarrhoea or heat exposure can also trigger palpitations. Caffeine, nicotine, energy drinks, some cold medicines and recreational drugs may stimulate the heart. Anxiety and adrenaline can create a strong, fast heartbeat. Less commonly, thyroid disease or an abnormal rhythm such as atrial fibrillation may be involved. A symptom does not identify its cause without an assessment.

Have the teenager stop activity, sit down and tell a trusted adult what they feel. Record the timing, duration, activity, fluids, sleep, medicines, caffeine and any dizziness or chest discomfort. Avoid energy drinks, nicotine and non-prescribed stimulants. Arrange a clinician appointment if episodes recur, happen at rest, interrupt sleep, or there is a family history of sudden unexplained death or inherited heart problems. Do not start iron or other supplements without advice.

Get emergency help for palpitations with fainting, chest pain, severe breathlessness, collapse, confusion or a heartbeat that remains very fast or irregular after stopping activity. Urgent review is also appropriate when symptoms begin during exercise, especially if the teenager has nearly fainted.

Ask whether an ECG, blood count, iron studies or thyroid test is needed, whether sports should pause temporarily, and which family-history details matter.