Heart palpitations when exercising

Exercise makes the heart beat faster and more forcefully to supply working muscles, so you may notice pounding during a hard effort. Deconditioning, heat, dehydration, caffeine, illness and low blood sugar can make the sensation stronger. Palpitations that start abruptly, feel uneven, or seem out of proportion to the activity can reflect an arrhythmia. Anaemia and an overactive thyroid may also present with palpitations and reduced exercise tolerance.

Stop or reduce the intensity when an unusual episode starts; sit or walk slowly until you feel settled. Do not restart the session to test yourself. Make a note of the activity, intensity, temperature, hydration, stimulants and symptoms. Arrange medical review before strenuous exercise if episodes recur, begin with modest effort, or occur with dizziness or unusual breathlessness. A clinician may examine you and arrange an electrocardiogram, blood tests or rhythm monitoring.

Call emergency services for palpitations with chest pain, fainting, collapse, severe breathlessness or confusion. Stop exercising and seek urgent advice for persistent rapid or irregular beats, marked dizziness or sudden weakness. These symptoms matter even if they improve after rest.

Ask whether your symptoms require rhythm testing, whether any medicine or supplement affects exercise, and what level of activity is appropriate while you wait. Tell the clinician about family heart history, recent infections and any episodes at rest.