Heart palpitations when sitting down: what to know

A transition from standing or walking to sitting can make you pay closer attention to your heartbeat. A recent burst of activity, a warm environment, anxiety, caffeine, nicotine, alcohol, fever or dehydration may explain a temporary change. Anaemia and an overactive thyroid can produce a faster pulse across different situations. An irregular rhythm, including atrial fibrillation, can also be noticed during quiet rest. Seated palpitations alone cannot show which explanation applies.

Sit securely, loosen restrictive clothing and slow your breathing without forcing deep breaths. Drink water if you can, and pause caffeine, nicotine and alcohol. Keep a simple record of posture changes, activity, meal timing, medicines, duration and whether the beat felt regular. Arrange an appointment if symptoms keep returning or affect sleep, work or exercise. A clinician may check your pulse, blood pressure, blood count, thyroid function and heart rhythm.

Seek emergency help for chest pain, severe shortness of breath, fainting, collapse, new confusion or a heartbeat with marked weakness. Obtain urgent medical advice when a fast or uneven rhythm continues with dizziness, or when you have known heart disease. Remain seated and avoid driving while unwell.

Ask what your symptom record suggests, whether an ECG or ambulatory monitor is useful, and whether medicines or supplements could contribute. Mention breathlessness, swelling, faintness and recent infections.