Bad heart palpitations: what to know

Palpitations are an awareness of your heartbeat. Stress, poor sleep, caffeine, nicotine, fever, dehydration or low blood sugar can make the heart feel faster or harder. Anaemia and an overactive thyroid can also contribute. Sometimes an irregular rhythm, such as atrial fibrillation, is responsible; the sensation alone cannot identify which explanation applies.

Note whether the rhythm feels fast, irregular, forceful or like missed beats. Record when it starts, what you were doing, how long it lasts and symptoms such as breathlessness, chest discomfort or light-headedness.

Stop exertion and sit somewhere safe. Breathe slowly and avoid caffeine, nicotine, alcohol and stimulant products until you have advice. Sip fluids if dehydration is possible, and follow your usual plan for diabetes if low blood sugar is a concern. Arrange a medical review for recurrent, worsening or unexplained episodes; an examination and heart tracing may help identify the rhythm.

Call emergency services for palpitations with chest pain, severe breathlessness, fainting, new confusion, blue lips or marked weakness. Seek urgent care if the heartbeat remains very fast or irregular, or if dizziness makes standing unsafe. Do not drive yourself during a severe episode.

Ask whether you need an electrocardiogram, blood tests for anaemia or thyroid problems, and a monitor for intermittent symptoms. Discuss your caffeine, medicines, supplements, menstrual bleeding, hydration and family history of rhythm problems.