Heart palpitations: causes, when they are harmless, and red flags
Last updated September 3, 2026.
Palpitations are the sensation of noticing your own heartbeat: racing, pounding, fluttering, flip-flopping, or skipped beats. The sensation feels alarming, but most palpitations are benign, driven by stimulants, stress, or normal extra beats that almost everyone has. The sorting question is always the same: what comes with the palpitations, and what triggers them.
What usually causes palpitations?
- Stimulants: caffeine, nicotine, energy drinks, decongestants like pseudoephedrine, some ADHD medications
- Stress, anxiety, and panic: adrenaline surges produce a racing, pounding heart, sometimes with breathlessness
- Ectopic beats: extra heartbeats almost everyone gets; they feel like a skip or thud, and a burst of them feels like fluttering
- Body states: fever, dehydration, low blood sugar, poor sleep, alcohol, pregnancy
- Medical causes: anemia, overactive thyroid, low potassium or magnesium, and actual rhythm problems like atrial fibrillation or SVT
When are palpitations likely harmless?
Reassuring patterns: brief flutters or skips that last seconds, a clear trigger (third coffee, bad night of sleep, stressful week), symptoms that fade when the trigger is removed, and palpitations with no other symptoms in an otherwise healthy person. Exercise-induced awareness of a pounding heart that settles within a minute or two of stopping is normal. A pulse that is fast but regular and under about 120 at rest with a clear cause is usually not dangerous.
When do palpitations need medical attention?
Get checked promptly (days, not months) for palpitations that keep recurring without an obvious trigger, last minutes to hours, or come with a known heart condition, a family history of sudden death at a young age, or pregnancy. Useful tests are an ECG, blood work for anemia, thyroid, and electrolytes, and sometimes a wearable monitor that records the rhythm during an episode, since catching the rhythm during symptoms is the single most useful piece of information.
When are palpitations an emergency?
Call emergency services now if palpitations come with chest pain, shortness of breath, fainting or near-fainting, severe dizziness, or a racing heart that does not settle. A sustained very fast pulse (over 150 at rest) that is not coming down, especially in someone with heart disease, is also an emergency-room situation rather than a wait-and-see one. Pymander's escalation routing is built and tested specifically for this class of decision; see the safety architecture working paper.
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Common questions
Why does my heart keep skipping beats?
Skipped beats are usually ectopic beats, extra heartbeats that nearly everyone gets. The skip you feel is actually the pause after the extra beat, and the thud is the next stronger beat. They become noticeable with caffeine, stress, poor sleep, alcohol, or lying on your left side at night, and they are benign in a structurally normal heart. They merit a check when they come in long runs, are increasing steadily, or come with dizziness, chest pain, or breathlessness, or when you have known heart disease. A simple ECG and sometimes a wearable monitor settle what they are.
Can anxiety cause heart palpitations?
Yes, and it is one of the most common causes. Adrenaline released during stress or panic makes the heart race and pound, and the sensation of the racing heart then feeds more anxiety, creating a loop. Anxiety-driven palpitations typically come with other signs like breathlessness, tingling hands, or a sense of dread, and they fade as the surge passes. That said, the safe move on a first episode is treating it as possibly physical: anemia, thyroid overactivity, and rhythm problems are checked with simple tests, and getting that reassurance is reasonable rather than excessive.
When should I worry about heart palpitations?
Worry less about the sensation itself and more about company it keeps. Same-day or emergency care is right for palpitations with chest pain, shortness of breath, fainting or near-fainting, or severe dizziness. A prompt appointment is right for palpitations that are new and recurring without a trigger, last minutes to hours, feel chaotic and irregular, or happen in someone with heart disease, a family history of sudden young death, or pregnancy. Brief flutters with a clear trigger and no other symptoms in a healthy person are almost always benign.
What tests check palpitations?
The standard workup is an ECG (a snapshot of the rhythm), blood tests for anemia, thyroid function, and electrolytes like potassium and magnesium, and often a wearable monitor. The monitor matters most: a 24-hour to two-week Holter or patch monitor, or a smartwatch ECG during an episode, catches the rhythm while you actually feel the symptoms, which is the one piece of information that separates a benign extra beat from a true arrhythmia. If episodes are infrequent, keeping a note of date, time, duration, and trigger sharpens the picture.
Can a doctor evaluate palpitations over text or video?
Mostly yes for the first pass. Palpitation assessment leans heavily on history: how episodes start and stop, how long they last, whether the rhythm feels regular or chaotic, triggers, stimulant use, and associated symptoms. That history, plus any smartwatch ECG you can share, is often enough to sort benign from needs-testing and to order the right blood work and a monitor. The hands-on parts (an in-person ECG, listening to the heart) come after. Texting an AI doctor is a quick way to find out which category your pattern fits.