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What to do if…
your heart suddenly starts racing or pounding while you are at rest

Produced and maintained by PanicStation.org Published: Last reviewed: Editorial policy UK guide

Short answer

Sit or lie down, stop exertion, and check for emergency symptoms. If you currently have palpitations with chest pain or tightness, shortness of breath, feeling faint, fainting, dizziness, or lightheadedness, call 999 now.

Do not do these things

  • Do not drive yourself to A&E.
  • Do not try to exercise it away.
  • Do not take extra doses of heart or blood pressure medicines, aspirin, or someone else’s medication unless a clinician has told you to.
  • Do not add stimulants now, such as energy drinks, lots of caffeine, nicotine, alcohol, or recreational drugs.
  • Do not start a new cold, flu, decongestant, or stimulant medicine for this unless a pharmacist or clinician says it is suitable for you.
  • Do not ignore it if it is new, happens at rest, does not settle, or keeps coming back.

What to do now

  1. Sit with back support or lie down. If you feel faint, lie flat and raise your legs slightly if you can do that safely.
  2. Call 999 now, or have someone take you to A&E without you driving, if the palpitations are happening now and you have any of these:
    • chest pain, pressure, or tightness
    • pain spreading to your arm, jaw, back, neck, or stomach
    • shortness of breath
    • dizziness or lightheadedness
    • fainting, blacking out, or feeling like you might faint
  3. If there are no emergency symptoms, note what is happening without delaying help:
    • the time it started
    • whether it began while sitting, lying down, sleeping, eating, using caffeine, using nicotine, drinking alcohol, taking a medicine, or feeling unwell
    • whether the pulse feels regular, irregular, very fast, fluttery, or like skipped beats
    • any smartwatch heart-rate or ECG reading you already have
  4. Reduce strain for the next few minutes:
    • keep sitting or lying down
    • loosen tight clothing
    • avoid standing up quickly
    • sip water if you may be dehydrated and can swallow normally
    • pause caffeine, nicotine, alcohol, and recreational drugs
  5. If a clinician has previously taught you a manoeuvre for a fast regular rhythm, use only what you were taught, and only if you have no chest pain, breathlessness, dizziness, or faint feeling. If you have not been taught one, do not experiment.
  6. If the palpitations do not go away, are getting worse, or you feel unable to manage them, call 111 where available, use 111 online in England, or use your local NHS urgent advice route.
  7. If the episode has stopped but it was new, unusually strong, lasted more than a few minutes, or keeps recurring, ask your GP surgery for an urgent appointment, call 111 where available, or use your local NHS urgent advice route.
  8. Seek advice sooner if you have known heart disease, a known arrhythmia, pregnancy or recent birth, a recent heart procedure, fever or severe infection, significant dehydration, or a recent medicine change that may affect heart rhythm.

What can wait

  • You do not need to work out the exact cause right now.
  • You do not need to decide today about long-term tests or treatment.
  • You do not need to keep checking your pulse again and again once you have noted the key details.
  • You do not need to search for every possible cause while the episode is happening.

Important reassurance

A racing or pounding heartbeat can feel frightening, and many episodes are not dangerous. The safest first move is to stay still, check for emergency symptoms, and use NHS help if it does not settle or you feel unwell.

Scope note

These are first steps for the first minutes or hours. If episodes recur, a clinician may later suggest checks such as an ECG, heart monitoring, blood tests, or a medicine review.

Important note

This is general information and not legal, medical, financial, therapeutic, or professional advice. It is not a diagnosis or a substitute for urgent care. If you think this may be an emergency or you feel seriously unwell, call 999.

Additional Resources

Closely connected guides that may be useful during the same situation or its immediate aftermath.

About this guide

This guide was produced and is maintained by PanicStation.org using its published editorial process. Official and specialist sources are checked where relevant, and AI-assisted tools may be used for drafting, organisation, and consistency checks. The site operator remains responsible for publication, revision, and removal decisions.

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