Heart palpitations when sitting: what to know

Sitting is a resting position, but your heart may still respond to recent activity, heat, pain, worry, caffeine, nicotine or a medicine. Dehydration reduces available fluid and can make the pulse faster. Anaemia and hyperthyroidism can increase the heart’s workload. Atrial fibrillation and other rhythm changes may cause an uneven or intermittently rapid beat. The fact that palpitations happen while sitting does not identify one diagnosis.

Stay seated, relax your shoulders and breathe gently. Check whether the sensation is a steady fast beat, a skipped beat or an irregular rhythm if you can do so comfortably. Avoid caffeine, nicotine and strenuous activity until it passes. Write down the time, duration, recent food or drink, medicines and symptoms such as dizziness. Book a clinician review when episodes repeat, last longer or interfere with daily activities.

Call emergency services if palpitations come with chest pain, severe breathlessness, fainting, collapse or profound weakness. Get urgent advice for a sustained fast or irregular heartbeat with dizziness, or for episodes in someone with known heart disease. Do not drive if you might faint.

Ask whether an ECG, blood count, thyroid test or rhythm monitor could clarify the cause. Tell the clinician about stimulants, supplements, prescribed medicines and any recent illness or fluid loss.