Fever and heart palpitations: what to know

When body temperature rises, the heart may beat faster to help circulate blood and release heat. Sweating, vomiting, diarrhoea or poor intake can reduce circulating fluid and make the pulse feel forceful or irregular. Anxiety, low blood sugar and anaemia can also produce awareness of the heartbeat. Hyperthyroidism may cause ongoing racing or pounding, while atrial fibrillation can cause an irregular rhythm. Heart failure may cause breathlessness, swelling or reduced exercise tolerance. These conditions cannot be distinguished reliably by sensation alone.

Sit or lie down, cool your surroundings, and take small sips of fluid if you can drink safely. Avoid strenuous activity, nicotine, caffeine and alcohol until the episode settles. Note when the palpitations start, whether the rhythm feels regular or irregular, how long they last, and whether fever, medication, stress or missed meals preceded them. Do not stop prescribed heart or thyroid medicine without advice.

Seek emergency help for chest pain, severe breathlessness, fainting, confusion, blue or grey lips, or palpitations with marked weakness. Arrange prompt medical assessment if the heartbeat remains fast or irregular at rest, episodes recur, or fever is accompanied by poor fluid intake and very little urine. People with known heart disease, thyroid disease, anaemia or pregnancy should seek advice earlier when symptoms are new or stronger than usual.

Ask whether you need an ECG, blood tests or a medication review. Describe your pulse sensation, temperature, fluid intake, medical history and any supplements, decongestants or stimulants you use.