Heart racing for no reason: what to know

Palpitations can feel like pounding, fluttering, skipping, or a sudden fast beat. They may start during rest even when you have not noticed an obvious trigger. A fast heartbeat can accompany Generalised Anxiety Disorder, while Dehydration, Hypoglycaemia, Anaemia, Iron Deficiency Anaemia, and Hyperthyroidism can also place extra demand on the heart. Atrial Fibrillation is a rhythm condition that can present with an irregular or racing heartbeat; Heart Failure may cause breathlessness and other symptoms alongside palpitations.

The feeling alone cannot identify the cause. A clinician may ask about medicines, caffeine, illness, sleep, menstrual bleeding, and the timing of each episode, then decide whether an examination or heart tracing is needed.

Stop strenuous activity, sit somewhere safe, and breathe slowly. Note when the sensation began, whether the beat feels regular or uneven, what you were doing, and any accompanying symptoms. Avoid extra caffeine, nicotine, and stimulant products until you have advice. Drink fluids if you may have lost them through heat, sweating, vomiting, or diarrhoea, unless a clinician has told you to restrict fluids. Arrange a routine appointment if episodes recur, last longer, or disturb sleep.

Seek emergency help if a racing or irregular heartbeat comes with chest pain or pressure, severe breathlessness, fainting, new confusion, or marked weakness. Get prompt medical advice if episodes keep returning, your heartbeat remains fast while resting, or you have known heart disease. Do not drive yourself if you feel faint or seriously unwell.

Ask whether your symptoms need an electrocardiogram, blood tests for anaemia or thyroid activity, or a monitor to capture an episode. Mention every prescription, supplement, inhaler, and non-prescription product you use.