Palpitations
Palpitations — the sensation of a racing, pounding or irregular heartbeat — are common and have many causes. Thyroid overactivity is a recognised contributor, but anxiety, caffeine, and heart rhythm problems are equally or more common.
This page helps distinguish when thyroid evaluation is appropriate.
Last medically reviewed: 1 November 2025
Key points
- Palpitations are a common feature of an overactive thyroid.
- They can also occur with anxiety, arrhythmia and other conditions.
- A racing or irregular heartbeat with chest pain needs urgent assessment.
- Treating hyperthyroidism usually improves palpitations.
Thyroid connection
Hyperthyroidism increases heart rate and contractility — thyroid hormone directly stimulates the heart. Patients often notice resting tachycardia, palpitations on exertion, or an irregular pulse.
Atrial fibrillation — an irregular, often rapid heart rhythm — is a recognised complication of hyperthyroidism, particularly in older patients.
Other causes
Anxiety and panic attacks, caffeine and stimulants, nicotine, anaemia, low blood sugar, dehydration, electrolyte imbalance, and primary arrhythmias (SVT, atrial fibrillation, premature beats) all cause palpitations.
In many cases, palpitations are benign — but new or persistent palpitations deserve evaluation.
Evaluation
Thyroid testing (TSH, free T4) is appropriate when palpitations accompany hyperthyroid features — weight loss, heat intolerance, tremor — or occur with an irregular pulse on examination.
An ECG is often the first test; ambulatory monitoring (Holter) may be needed for intermittent symptoms. If thyroid tests are normal, cardiac evaluation continues.
Frequently asked questions
Can hypothyroidism cause palpitations?
Rarely — hypothyroidism typically slows the heart. However, palpitations can occur if hypothyroidism coexists with other causes or if medication dose is excessive.
Is atrial fibrillation from thyroid reversible?
Often yes — treating the underlying hyperthyroidism can restore normal rhythm, though some patients have persistent AF needing ongoing management.
When are palpitations an emergency?
Palpitations with chest pain, severe breathlessness, fainting, or a sustained very rapid irregular pulse need urgent assessment.
References & further reading
This page is based on established medical knowledge and guidelines from authoritative sources. Always consult a qualified clinician for personal medical advice.
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