Heart palpitations are moments when you become unusually aware of your heartbeat. They can feel like your heart is fluttering, pounding, racing, or skipping beats. Most of the time, palpitations are harmless and triggered by something temporary like stress, caffeine, or exercise. They’re common enough that roughly 684,000 emergency department visits per year in the United States list palpitations as the primary reason for the visit.
What Palpitations Actually Feel Like
People describe palpitations in several different ways, and the sensation varies depending on what’s happening electrically in the heart. Some feel a rapid fluttering in the chest, as if a butterfly were trapped behind the ribcage. Others notice a heavy pounding that seems louder and stronger than normal. Some experience a sudden “thud” followed by a brief pause, which feels like the heart skipped a beat entirely.
That skipped-beat sensation is usually caused by a premature beat, an extra heartbeat that fires slightly early. When the heart contracts before it has fully filled with blood, the beat feels weak or absent. The next beat, which comes after a slightly longer pause, hits harder because the heart has had extra time to fill. The result is that unsettling “flip-flop” feeling. These premature beats can originate in the upper chambers of the heart (called premature atrial contractions, or PACs) or in the lower chambers (premature ventricular contractions, or PVCs). Both are extremely common in healthy people.
You might notice palpitations in your chest, throat, or neck. They can last a few seconds or continue for minutes. Some people experience them only when lying down at night, when the quiet makes it easier to notice their heartbeat.
Common Triggers
The most frequent cause of palpitations is anxiety. Stress, fear, panic attacks, and even depression can all make the heart beat harder or faster in ways you can feel. Strong emotions trigger your body’s fight-or-flight response, which releases adrenaline and speeds up the heart.
Stimulants are another major trigger. Caffeine, nicotine, cocaine, and amphetamines can all provoke palpitations. Cold and cough medications containing pseudoephedrine, as well as some asthma inhalers, act as stimulants and have the same effect. Alcohol is a well-documented trigger too, particularly for atrial fibrillation, a type of irregular rhythm.
Physical factors that can set off palpitations include:
- Strenuous exercise, especially if you’re not conditioned for it
- Dehydration or low blood sugar
- Fever, which raises the heart rate
- Lack of sleep, which research identifies as one of the most common self-reported triggers among people with irregular heart rhythms
- Hormonal changes during menstruation, pregnancy, or menopause
- Spicy food
In many cases, palpitations come and go without a clear trigger at all. That’s normal. The heart produces electrical impulses continuously, and occasional misfires are part of how the system works.
Medical Conditions That Cause Palpitations
While most palpitations are benign, they can sometimes signal an underlying condition. An overactive thyroid gland (hyperthyroidism) speeds up the metabolism and heart rate, often causing a persistent fluttering sensation. An underactive thyroid can also contribute. Anemia, where the blood carries less oxygen than normal, forces the heart to pump faster to compensate, producing noticeable pounding.
Low potassium, low oxygen levels, and other electrolyte imbalances affect the heart’s electrical signals directly. Blood loss and significant dehydration can do the same by reducing blood volume, which makes the heart work harder with each beat.
Heart-related causes include irregular rhythms (arrhythmias), structural changes in the heart, valve problems, and congenital heart disease. Atrial fibrillation is the most well-known arrhythmia associated with palpitations. In atrial fibrillation, chaotic electrical signals cause the upper chambers to quiver instead of contracting in an organized way, producing an irregular and often rapid heartbeat. People with a history of heart disease, heart surgery, or heart attack are more likely to experience palpitations tied to a cardiac cause.
When Palpitations Are Concerning
Isolated palpitations that last a few seconds, happen occasionally, and resolve on their own are rarely dangerous. The picture changes when palpitations come with other symptoms: chest pain, dizziness, fainting, or significant shortness of breath. These combinations suggest the heart may not be pumping blood effectively during the episode.
Your palpitations are more likely to reflect an abnormal heart rhythm if you have existing heart disease, significant risk factors for heart disease (like high blood pressure, diabetes, or smoking), or an abnormal heart valve. Palpitations that start suddenly, feel very fast, and last for minutes rather than seconds deserve prompt attention, especially if they happen during rest rather than during exercise or stress.
How Palpitations Are Evaluated
The challenge with diagnosing palpitations is that they’re often gone by the time you see a doctor. The first step is usually an electrocardiogram (ECG), a quick, painless test where sticky patches on your chest record the heart’s electrical activity. If the ECG is normal, which it often is because the palpitations aren’t happening at that moment, the next step is typically some form of portable monitoring.
A Holter monitor is a small device you wear for one to two days while going about your normal routine. It records every heartbeat continuously, capturing any irregularities that occur during that window. If your palpitations are less frequent than once a week, an event recorder may be more useful. You wear it for up to 30 days and press a button when you feel symptoms, which saves the heart rhythm data from that moment for your doctor to review later.
An echocardiogram, which uses ultrasound to create images of the heart’s structure and blood flow, may be ordered if there’s any suspicion of a structural problem like a valve issue. Blood tests to check thyroid function, potassium levels, and red blood cell count help rule out the non-cardiac causes. Some smartwatches now offer ECG monitoring that can capture rhythm data during an episode, which can be genuinely useful to bring to an appointment.
Stopping Palpitations in the Moment
For benign palpitations, a few techniques can help slow the heart by activating the vagus nerve, which acts as a brake on heart rate. The simplest is the Valsalva maneuver: take a deep breath and bear down as if you’re straining, holding for 10 to 15 seconds. A modified version where you do this while sitting upright, then immediately lie flat with your legs raised to a 45-degree angle for about a minute, has shown conversion rates of around 40% for certain fast rhythms, more than double the standard technique.
Splashing ice-cold water on your face or submerging your face in a basin of cold water triggers the diving reflex, another vagal response that slows the heart. Taking slow, deep breaths and exhaling longer than you inhale accomplishes something similar, though more gently.
For longer-term prevention, the most effective strategies target triggers directly. Cutting back on caffeine and alcohol, getting consistent sleep, managing stress, staying hydrated, and avoiding decongestant medications when possible all reduce the frequency of episodes. Regular moderate exercise, somewhat paradoxically, tends to decrease palpitations over time even though intense exertion can trigger them in the short term.