What do palpitations feel like with hyperthyroidism?

An overactive thyroid releases more thyroid hormone than the body needs. This can make the heart respond more strongly to normal signals and can disturb its rhythm. The pattern may be steady and rapid or feel irregular. Palpitations have many possible causes, so symptoms cannot establish hyperthyroidism by themselves; an examination and thyroid blood tests may be needed.

Arrange a medical appointment if palpitations keep returning or appear with heat intolerance, tremor, sleep difficulty or unexplained weight change. Write down the episode pattern and list medicines, supplements, energy drinks and decongestants. Take prescribed thyroid treatment exactly as directed, and do not start iodine or another thyroid product without professional guidance.

Call emergency services if palpitations come with chest pain, fainting, severe breathlessness, confusion, collapse or extreme weakness. Prompt assessment is also needed for a persistent very rapid heartbeat, especially with fever, marked agitation or worsening illness. Rest while waiting and avoid driving if dizzy.

Ask whether thyroid tests, an electrocardiogram or rhythm monitoring are appropriate. Tell the clinician about eye changes, neck swelling, bowel changes, menstrual changes, sleep problems and family thyroid history. Ask how to recognise a treatment-related change in heartbeat and when your results should be reviewed.