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uk Health & medical scares fever and fast heart rate • fever with racing pulse • high pulse with mild fever • unusually fast heart rate fever • fever tachycardia feels wrong • shivering and rapid heartbeat • infection feels severe • possible sepsis symptoms • dehydration fast pulse fever • flu with fast heart rate • covid fever racing heart • palpitations with fever • lightheaded with fever • chest discomfort with fever • short of breath with fever • feeling very unwell fever • fever and confusion • fast pulse at rest • worried fever heart rate

What to do if…
you have a fever and your heart rate feels unusually fast for the temperature

Short answer

If your heart rate feels unusually fast at rest with fever—especially if you feel seriously unwell—get urgent triage now: call 999 or go to A&E for severe symptoms or if you suspect sepsis; otherwise call NHS 111 for same-day advice.

Do not do these things

  • Don’t “push through” with exercise, hot baths/saunas, or alcohol—these can raise your heart rate and worsen dehydration.
  • Don’t take extra doses of paracetamol/ibuprofen to chase your temperature down. Use only the packet directions.
  • Don’t accidentally double-dose by combining cold/flu products with paracetamol or ibuprofen (many “all-in-one” remedies already contain them).
  • Don’t ignore worsening symptoms because your fever “isn’t that high.” A fast pulse with feeling very unwell matters.
  • Don’t drive yourself to A&E if you’re faint, confused, very weak, or having chest pain—call 999.

What to do now

  1. Do a 60-second check and write it down (helps rapid triage).
    • Measure your temperature.
    • Count your pulse for a full 60 seconds while seated and resting.
    • Note any of these: severe breathlessness; chest pain/pressure; new confusion; fainting/near-fainting; blue/grey lips/skin; extreme shivering; skin that looks mottled/very pale; a new rash that does not fade when pressed; passing very little urine; severe or rapidly worsening pain; feeling you might collapse.
  2. Choose the urgent route based on red flags.
    • Call 999 or go to A&E now if you have any severe symptoms above, or you think you might have sepsis (for example: fever/shivering plus you feel dangerously unwell, with a very fast pulse at rest, severe breathlessness, confusion, collapse, mottled/blue skin, or very little urine).
    • Call NHS 111 now if you are stable but concerned (for example: your pulse is faster than usual at rest with fever, you’re getting worse, you’re struggling to keep fluids down, or you’re worried an infection is not behaving normally).
  3. While you’re arranging help, reduce strain on your body.
    • Sit upright or lie down if dizzy. Keep the room comfortably cool (not cold).
    • Sip fluids steadily (small sips every few minutes). If you’re vomiting, keep to frequent tiny sips.
    • If safe for you, take paracetamol or ibuprofen exactly as directed on the packet.
  4. Check if you’re in a higher-risk group (pushes toward urgent assessment).
    Seek urgent triage (111 or 999/A&E depending on severity) if you are pregnant or recently postpartum, immunocompromised (e.g., chemotherapy, transplant medicines, high-dose steroids), have significant heart/lung/kidney disease, have diabetes with concerning symptoms, or you’ve recently had surgery or an invasive procedure.
  5. Prepare one clear sentence for the call/triage.
    Example: “I have a fever and my heart rate feels unusually fast at rest. My readings are temp __ and pulse __. I also have [breathlessness/dizziness/reduced urination/confusion/chest discomfort].”

What can wait

  • You do not need to work out the exact cause right now (viral illness, dehydration, infection, etc.).
  • You do not need to keep rechecking your pulse every few minutes—focus on getting triage and following instructions.
  • You can postpone decisions about work/school and plans until you’ve been assessed and are stable.

Important reassurance

A faster heart rate can happen with fever, pain, dehydration, and anxiety. Noticing that it feels “out of proportion” is still worth acting on—getting prompt triage is a safe, sensible step.

Scope note

This is first-steps-only guidance to stabilise you and get you to the right level of care. Further decisions and treatment depend on assessment.

Important note

This is general information, not a diagnosis. If you think you’re deteriorating, trust that instinct and seek urgent help.

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