Fatigue and palpitations: what to know

Palpitations are sensations such as fluttering, pounding or a heartbeat that feels unusually fast. They may occur after exertion, poor sleep, emotional strain, caffeine or some medicines. Dehydration can reduce circulating fluid and make the heart beat faster. Anaemia, including iron deficiency anaemia, can leave the body carrying less oxygen, prompting a faster heartbeat and tiredness. An overactive thyroid may cause heat intolerance, tremor and weight change alongside palpitations. Anxiety can produce a real surge in heartbeat without proving that anxiety is the cause.

Atrial fibrillation is a heart rhythm condition that can present with palpitations and fatigue; heart failure can present with tiredness and breathlessness, sometimes with swelling. These conditions cannot be diagnosed from symptoms alone.

Record when episodes start, how long they last, what the heartbeat feels like, and whether activity, caffeine, illness, stress or missed meals preceded them. Rest somewhere cool, drink fluids if you can, and avoid energy drinks, nicotine and excess caffeine until you have advice. Arrange a primary-care appointment if symptoms recur, interfere with daily activity or are accompanied by unusual tiredness. A clinician may review medicines and check blood count, iron, thyroid function, glucose and heart rhythm.

Seek emergency help for palpitations with chest pressure or pain, severe breathlessness, fainting, new confusion, blue or grey lips, or marked weakness. Get prompt medical advice for a sustained very fast or irregular heartbeat, repeated episodes, or symptoms after a new medicine. Do not drive yourself if you feel faint or seriously unwell.

Ask whether your symptoms need an electrocardiogram, blood tests for anaemia or thyroid disease, or monitoring over time. Tell the clinician about pregnancy, heavy bleeding, recent illness, supplements, medicines and family history of rhythm problems.