11 minute read
Medically reviewed by Dr Ravi Assomull, Consultant Cardiologist – July 2026
Key takeaways
- Palpitations - the sensation of your heart racing, pounding, fluttering or skipping - are extremely common and usually harmless.
- Red flags are palpitations with chest pain, blackouts or severe breathlessness (call 999), and palpitations that are prolonged, fast and erratic, triggered by exercise, or paired with a family history of sudden death - see a cardiologist promptly.
- The commonest significant cause is atrial fibrillation, which raises stroke risk roughly five-fold and is very treatable once found.
- Diagnosis usually needs the heart to be "caught in the act" - which is what home ECG monitors worn for days or weeks are for.
Everyone's heart occasionally does something odd: a thud, a flutter, a skipped beat, a brief gallop after a stressful email. The medical term is palpitations - simply an awareness of your own heartbeat - and it is one of the most common reasons people search for a cardiologist in London. It is also one of the most common reasons they don't book: because the sensation passes, and "it's probably nothing" wins the argument.
Usually it is nothing. But palpitations sit on a spectrum from completely benign to genuinely important, and the two ends can feel remarkably similar from the inside. This guide - written from the perspective of a consultant cardiologist who investigates palpitations every working week - explains what causes them, which patterns matter, exactly when to seek help, and how we find the answer.
What do palpitations feel like?
Patients describe palpitations in wonderfully varied language, and the description genuinely helps diagnosis:
- A skipped beat, or a thud/flip in the chest - often an ectopic beat: an early beat followed by a compensatory pause, then a stronger beat you feel as the "thump".
- A fast, regular racing - as if the heart has changed gear. May be a normal response to adrenaline, or a rhythm such as supraventricular tachycardia (SVT) - see our page on fast heartbeats.
- A fast, chaotic, irregular fluttering - "like a bag of worms" or "a drum solo" - the classic description of atrial fibrillation (AF).
- A slow, heavy pounding - each beat felt forcefully, sometimes with a slow heart rate.
- A fluttering in the neck - a small but useful clue that often points to specific electrical rhythms.
Noticing how yours feel - and ideally tapping the rhythm out on a table when you see a doctor - is more useful than you might think.
The common, usually harmless causes
Most palpitations come from everyday physiology rather than heart disease:
- Stimulants: caffeine (coffee, energy drinks, pre-workout supplements), nicotine, alcohol - both during drinking and the morning after - and some decongestant cold remedies.
- Stress and anxiety: adrenaline is the body's own stimulant. The relationship runs both ways - palpitations cause anxiety, anxiety causes palpitations - which is precisely why objective testing is so valuable. Our article on chronic stress and the heart explores the longer-term picture.
- Poor sleep: short or fragmented nights measurably increase ectopic beats - one more reason sleep matters to your heart.
- Hormonal shifts: pregnancy, the perimenopause and thyroid changes all commonly cause palpitations; an overactive thyroid is a classic - and very treatable - culprit found on blood tests.
- Exercise and recovery: awareness of a strong heartbeat after training is normal; palpitations during peak effort are a different matter (see red flags below).
- Fever, dehydration and low blood sugar.
Isolated ectopic beats deserve a special mention because they are near-universal: virtually everyone has some, most people never feel them, and in a structurally normal heart they are benign even when frequent enough to feel. The reassurance, though, should come after the heart has been checked - not instead of checking.
The causes that matter
Atrial fibrillation - the one we most want to find
Atrial fibrillation is the most common significant arrhythmia, affecting well over a million people in the UK - many of them undiagnosed. The upper chambers of the heart quiver instead of beating in an organised way, producing an irregular, often fast pulse. Untreated, AF raises the risk of stroke roughly five-fold, because blood pooling in the quivering atrium can clot. Found and treated - with anticoagulation where indicated, rate or rhythm control, cardioversion or catheter ablation - that risk falls dramatically. AF can be intermittent (paroxysmal), which is exactly why it evades one-off ECGs and why we so often ask patients to learn its warning signs.
Other rhythm disturbances
Supraventricular tachycardia (sudden-onset, sudden-offset racing, often in younger people), atrial flutter, and - rarely but importantly - ventricular arrhythmias, which are the reason palpitations during exertion or with blackouts are treated seriously. Slow rhythms and pauses (abnormal heart rates) can also be felt as palpitations, sometimes needing a pacemaker when they cause symptoms.
Structural and other medical causes
Palpitations can be the presenting symptom of an overactive thyroid, anaemia, valve disease, cardiomyopathy or previous silent heart damage - which is why assessment includes more than a rhythm strip.
When to worry: the red flags
Call 999 now if palpitations come with:
- Chest pain or pressure
- Fainting, or feeling about to faint
- Severe breathlessness
- They follow a collapse, or occur in someone with a known serious heart condition and feel different from usual
See a cardiologist promptly (days, not months) if your palpitations:
- Feel fast and irregular ("chaotic"), or last more than a few minutes at a time
- Occur during exercise rather than after it
- Come with dizziness, near-blackouts or unusual breathlessness
- Are happening more often, or waking you at night
- Occur alongside a family history of sudden unexplained death, cardiomyopathy or inherited heart disease
- Simply worry you enough that you're reading this - health anxiety resolves with answers, not reassurance from strangers on the internet
Our broader guide to when to see a cardiologist puts palpitations alongside the other eleven signs worth acting on.
How a cardiologist finds the answer
The central challenge with palpitations is that they rarely perform on cue: by the time you're in a clinic, your rhythm is usually behaving perfectly. Investigation is therefore built around catching the heart in the act:
- History first. The pattern - onset, offset, regularity, triggers, duration - narrows the field dramatically before any test. Tap the rhythm on the desk; it helps.
- Resting ECG: a baseline snapshot. It may catch the rhythm directly; even when it doesn't, it can reveal electrical signatures that predispose to arrhythmias.
- Ambulatory ECG monitoring: the workhorse. A small wearable recorder - 24 hours, 48 hours, 7 or 14 days depending on how often your symptoms occur - worn at home while you live normally. You log symptoms; we match the log against the recording. This correlation between what you felt and what the heart did is the diagnostic gold standard.
- Echocardiogram: an ultrasound to confirm the heart is structurally normal - which transforms the meaning of ectopic beats from "worrying" to "benign".
- Blood tests: thyroid, electrolytes, anaemia, and cardiac markers where relevant.
- Exercise ECG or stress echo: when symptoms are exertional, we reproduce the conditions safely and watch.
- Implantable loop recorder: for rare-but-important episodes - a device smaller than a USB stick, inserted under the skin in minutes, that monitors continuously for up to three years.
At our Harley Street clinic the consultation, ECG, echocardiogram and monitor fitting typically all happen at the first visit - the whole pathway that takes months of separate appointments elsewhere compressed into a single afternoon. Our guide to what happens at a private cardiologist appointment walks through it step by step.
What about smartwatches?
Genuinely useful - with caveats. Modern watches can record a single-lead ECG and flag irregular rhythms, and patients increasingly arrive with recordings that meaningfully speed up diagnosis; bring yours. But watches both miss arrhythmias and raise false alarms, and a single-lead trace cannot exclude structural disease. Treat a watch alert as a prompt for proper assessment, not a diagnosis - and treat a reassuring watch the same way if symptoms continue.
The most powerful combination we see in clinic is a watch trace plus a written diary: the recording shows what the rhythm did, the diary shows what you felt, what you were doing and what you'd consumed. Matched against a medical-grade monitor's output, that pairing routinely turns a vague six-month story into a one-visit diagnosis. If you do only one thing before your appointment, start the diary today - date, time, trigger, sensation, duration - and keep it running through the monitoring period.
Treatment: what happens if something is found
Almost always, something can be done - and usually a great deal:
- Benign ectopics: reassurance backed by a normal echo, trigger management (caffeine, alcohol, sleep, stress), and occasionally medication if they remain intrusive.
- Atrial fibrillation: stroke-risk assessment and anticoagulation where indicated, rate or rhythm control, electrical cardioversion to restore normal rhythm, or catheter ablation - a keyhole procedure treating the electrical source itself.
- SVT: teachable manoeuvres to stop episodes, medication, or ablation, which is frequently curative.
- Slow rhythms and pauses: a pacemaker, when symptoms and recordings justify it.
- Underlying causes: treating the thyroid, the anaemia, the blood pressure - palpitations are sometimes the messenger, not the disease.
What to do during an episode
Practical steps while palpitations are actually happening - all assuming none of the 999 red flags above are present:
- Sit down and breathe slowly. Long, slow exhalations (in for four counts, out for six) activate the vagus nerve, which naturally slows the heart. Many episodes settle within minutes.
- Check your pulse - or better, record it. Note whether it feels fast or slow, regular or chaotic, and roughly how many beats in 15 seconds. If you have a smartwatch with ECG capability, record a trace during the episode; that thirty-second strip can be worth more than a dozen normal clinic ECGs.
- Note the clock. When it started, when it stopped, and whether it ended abruptly (a useful electrical clue) or faded gradually.
- Avoid the reflex remedies. More coffee to "push through", a cigarette to calm down, or intense exercise to "reset" the rhythm are all counterproductive mid-episode.
- Afterwards, log it - trigger, duration, sensation - in a notes app or on paper. Two weeks of such a diary transforms a first consultation.
Reducing palpitations day to day
Whatever the eventual diagnosis, the same levers reliably reduce palpitation frequency - because they lower the heart's background irritability:
- Audit your stimulants honestly. Total caffeine (coffee, tea, energy drinks, pre-workout powders), alcohol - a notorious trigger both during drinking and the next morning - and nicotine. Trial two stimulant-light weeks and count episodes; the result is often persuasive.
- Protect sleep. Short, fragmented nights measurably increase ectopic activity. Our guide to sleep and heart health covers the practical steps.
- Manage the stress loop. Adrenaline triggers palpitations; palpitations trigger anxiety; anxiety produces more adrenaline. Breaking the loop - exercise, breathing practice, mind-body techniques - reduces both the symptom and the suffering attached to it.
- Stay hydrated and fed. Dehydration and low blood sugar are underrated triggers - see our piece on hydration and the heart.
- Keep moving. Regular moderate exercise lowers resting adrenaline and, over months, palpitation frequency - the caveat being that new exertional palpitations need assessment before you train through them.
Frequently asked questions
Are palpitations ever normal?
Yes - awareness of your heartbeat after exercise, during stress, with fever or after caffeine is a normal response. Occasional isolated ectopic beats in a structurally normal heart are also considered a variant of normal. The qualifier "structurally normal" is doing important work in that sentence, which is what an echocardiogram is for.
Can anxiety alone really cause palpitations?
Absolutely - adrenaline is a genuine cardiac stimulant, and anxiety is among the commonest causes we see. But "it's just anxiety" should be a conclusion reached after normal tests, not a label applied instead of them. Objective monitoring is often the single most effective treatment for health anxiety about the heart.
Should I stop exercising until I've been checked?
If your palpitations occur during exertion, or with chest pain or near-blackouts, pause vigorous training until you've been assessed - promptly, and mention it when booking. Post-exercise heart awareness without other symptoms rarely requires stopping, but assessment is still sensible. Athletes should read our piece on exercise-induced heart problems.
How quickly can I get palpitations investigated privately?
Consultation typically the next working day at 68 Harley Street; ECG and echocardiogram usually at the same visit, with a home monitor fitted where needed. Initial consultation £325, follow-up £275 - full details on our fees page, and no GP referral is needed.
The bottom line
Most palpitations are innocent. The important ones announce themselves through pattern - fast and chaotic, exertional, prolonged, or paired with warning symptoms - and every one of them is easier to treat found early. If your heart keeps interrupting your day, get it recorded, get it explained, and get on with your life.
Book an appointment with Dr Ravi Assomull - typically next working day - or call 020 3576 2885.
