Heart palpitations have a wide range of causes, from a second cup of coffee to an underlying heart rhythm disorder. In a study of 190 patients who reported palpitations, 43% had a cardiac cause, 31% were linked to anxiety or panic disorder, 6% were traced to medications or drugs, and 16% had no identifiable cause at all. The good news: most palpitations are temporary and harmless. But understanding what’s behind them helps you know when to pay attention.
What a Palpitation Actually Is
A palpitation is any awareness of your own heartbeat that feels abnormal. It might be a fluttering sensation, a pounding in your chest, a feeling that your heart skipped a beat, or a sudden racing. The sensation often comes from premature contractions, where one chamber of the heart fires slightly early, followed by a stronger-than-usual beat that you notice. These extra beats can originate in the upper chambers (premature atrial contractions) or the lower chambers (premature ventricular contractions, or PVCs). Both are extremely common and, in most cases, not dangerous.
Caffeine, Alcohol, and Nicotine
Caffeine is one of the most frequently reported triggers. It works by blocking a chemical messenger called adenosine, which normally helps keep your heart rate steady. When adenosine is blocked, stress hormones get more access to the heart, and calcium floods into heart muscle cells. That surge of calcium is what causes the extra beats. In a randomized trial, participants who drank coffee had a 54% increase in PVCs compared to those who avoided caffeine. Even a moderate amount, roughly two to three cups, can be enough to trigger them in sensitive individuals.
Alcohol is another common culprit. It’s one of the most frequently self-reported triggers among people with atrial fibrillation, and heavy drinking can provoke arrhythmias even in people without a diagnosed heart condition. The combination of alcohol with caffeine or nicotine raises the risk further. Nicotine stimulates the release of adrenaline, which speeds up the heart and can trigger premature beats on its own.
Stress, Anxiety, and Panic Disorder
Nearly a third of palpitation cases in one large study were caused by anxiety or panic disorder, making it the second most common cause after cardiac issues. When you’re anxious or under stress, your body releases adrenaline and cortisol, both of which increase heart rate and make the heart more excitable. During a panic attack, the heart can race to over 100 beats per minute, and the sensation itself often creates a feedback loop: you feel the palpitation, get more anxious, and the palpitations intensify.
Sleep deprivation plays into this cycle as well. Poor sleep raises baseline stress hormones and lowers the threshold for both anxiety and irregular heartbeats. Lack of sleep is consistently reported alongside alcohol and caffeine as a top trigger for symptomatic arrhythmias.
Thyroid Problems
Your thyroid gland controls your metabolic rate, and when it’s overactive (hyperthyroidism), it essentially puts the heart on fast-forward. Too much thyroid hormone increases heart rate, strengthens contractions, and makes the heart more prone to irregular rhythms. Palpitations are one of the hallmark symptoms. In hyperthyroidism, the hormone that regulates the thyroid (TSH) drops below 0.1, while thyroid hormones themselves climb above normal. An underactive thyroid can also cause palpitations, though less commonly. If palpitations come with unexplained weight changes, heat intolerance, or fatigue, a thyroid issue is worth investigating.
Electrolyte Imbalances
Your heart’s electrical system depends on a precise balance of minerals, especially potassium and magnesium. When these levels drop too low, from dehydration, heavy sweating, vomiting, or certain medications like diuretics, the electrical signals that coordinate each heartbeat become unstable. The result can be anything from occasional skipped beats to sustained irregular rhythms. This is one reason palpitations are more common during illness, after intense exercise, or when you haven’t been eating or drinking enough.
Medications That Trigger Palpitations
Several common medications list palpitations as a side effect. Asthma inhalers containing salbutamol (albuterol) are among the most likely to cause a fast heart rhythm. They work by relaxing the airways, but they also stimulate receptors in the heart that speed it up. Formoterol, another inhaler medication, caused a rapid heart rhythm in about 13% of patients in one analysis.
Certain antidepressants can also be triggers. Venlafaxine and similar drugs that affect both serotonin and noradrenaline can cause cardiovascular side effects, including palpitations and changes to the heart’s electrical timing. Theophylline, an older medication used for asthma and lung disease, belongs to the same chemical family as caffeine and can provoke arrhythmias even at normal doses in susceptible people. Decongestants containing pseudoephedrine are another well-known cause, as they mimic the effects of adrenaline on the heart.
Heart Rhythm Disorders
When palpitations stem from an actual arrhythmia, two of the most common types are supraventricular tachycardia (SVT) and atrial fibrillation (AFib).
Supraventricular Tachycardia
SVT causes a sudden, rapid heartbeat that starts and stops abruptly. You might feel a burst of pounding or fluttering that lasts seconds to minutes, sometimes accompanied by chest tightness, shortness of breath, or sweating. The heart rate during an episode can exceed 150 beats per minute. SVT originates from faulty electrical pathways above the ventricles and is more common in younger adults. It’s usually not life-threatening but can be alarming and disruptive.
Atrial Fibrillation
AFib involves chaotic electrical signals in the upper chambers of the heart. Instead of contracting in a coordinated rhythm, the atria quiver irregularly, and some of those disorganized signals make it through to the lower chambers, causing a fast and irregular heartbeat. During an episode, heart rates typically range from 100 to 175 beats per minute. Symptoms include palpitations, fatigue, dizziness, lightheadedness, shortness of breath, and reduced exercise tolerance. Some people with AFib notice no symptoms at all and only discover it during a routine exam. AFib increases the risk of blood clots and stroke, so it requires medical attention even when symptoms are mild.
Hormonal Changes
Fluctuations in estrogen and progesterone can make the heart more sensitive to palpitations. This is why many women first notice them during pregnancy, perimenopause, or around their menstrual period. Pregnancy increases blood volume by about 50%, which means the heart has to work harder with each beat. Perimenopause brings erratic hormone levels that can amplify the body’s stress response. These hormonally driven palpitations are generally benign but can be unsettling, especially if they appear suddenly in someone who has never experienced them before.
How Palpitations Are Diagnosed
Because palpitations are often intermittent, catching them on a standard electrocardiogram (ECG) in a doctor’s office can be hit or miss. If your resting ECG looks normal but you’re still having symptoms, the next step is usually a Holter monitor, a small wearable device that records your heart’s rhythm continuously for one to two days. If your palpitations happen less frequently than that, an event monitor can track your heart over several weeks, only saving data when you press a button during a symptom or when the device detects an abnormal rhythm. Blood tests for thyroid function, electrolyte levels, and anemia are typically part of the workup as well.
Symptoms That Need Immediate Attention
Most palpitations don’t require emergency care, but a few accompanying symptoms change the picture. Seek immediate help if palpitations come with chest pain lasting more than a few minutes, fainting or near-fainting, or significant shortness of breath. These combinations can signal a more serious arrhythmia or an underlying heart problem that needs urgent evaluation.