Heart palpitations are moments when you suddenly become aware of your heartbeat, whether it feels like it’s racing, fluttering, pounding, or skipping a beat. Most of the time, they’re harmless and triggered by something identifiable like stress, caffeine, or a poor night’s sleep. But they can also signal an underlying heart rhythm problem, so understanding the common causes helps you figure out what’s going on and whether you need to act.
What Actually Happens During a Palpitation
Normally, you don’t feel your heart beating at all. Palpitations happen when something changes your heart’s rate or rhythm in a way your body notices. The exact mechanism behind the sensation isn’t fully understood, but it’s thought to involve abnormal movement of the heart within the chest.
One of the most common types is a premature beat, sometimes called an “extra beat” or “skipped beat.” What’s interesting is that you probably aren’t feeling the premature beat itself. The early contraction blocks the next normal beat, which creates a slightly longer pause. During that pause, your heart fills with more blood than usual and then contracts more forcefully. That stronger-than-normal thump is what you actually feel. This is why palpitations often come with a sensation of the heart “dropping” or “lurching” before resuming its normal pattern.
Some people also have heightened awareness of completely normal heart activity, especially when something like exercise, fever, or anxiety has pushed their heart rate up. In these cases, nothing is wrong with the heart itself. Your nervous system is simply paying closer attention.
Caffeine, Alcohol, and Other Lifestyle Triggers
Caffeine is one of the first suspects people think of, and for good reason. That said, research from the British Heart Foundation suggests that moderate intake (around four to five cups of coffee per day) doesn’t increase the risk of abnormal heart rhythms in most people. The key word is “most.” Some people are significantly more sensitive to caffeine, and even a single cup can trigger noticeable palpitations in those individuals. If you’ve recently increased your coffee, tea, or energy drink intake and started noticing your heartbeat, that’s a strong clue.
Alcohol is another common trigger. It can disrupt the electrical signals in your heart, and binge drinking in particular is linked to episodes of atrial fibrillation, sometimes called “holiday heart syndrome.” Nicotine, whether from cigarettes or vaping, stimulates the same fight-or-flight pathways that speed up your heart during stress. Recreational drugs, especially stimulants, can do the same thing more aggressively.
Dehydration and skipping meals also deserve mention. Both can cause drops in blood pressure or blood sugar that your body compensates for by speeding up your heart rate, and that acceleration can register as palpitations.
Stress, Anxiety, and the Fight-or-Flight Response
Anxiety is one of the most common causes of palpitations, and the connection is direct. When you feel stressed or anxious, your body’s autonomic nervous system activates the fight-or-flight response. This floods your system with adrenaline, which increases your heart rate and makes contractions stronger. The result is a pounding, racing, or fluttering sensation in your chest, sometimes even when you’re sitting still.
During a panic attack, this effect can be extreme. Your heart may jump to 100 beats per minute or higher within seconds, and the sensation itself can create more anxiety, which feeds the cycle. Many people experiencing their first panic attack go to the emergency room convinced they’re having a heart attack. The palpitations from anxiety are generally not dangerous, but they can be deeply uncomfortable and frightening.
Chronic stress works more subtly. It keeps your baseline adrenaline levels slightly elevated, which means your heart rate stays a little higher than it should throughout the day. You might notice palpitations more at night when you lie down and external distractions quiet down, leaving you alone with the sensation.
Medications That Can Cause Palpitations
Several over-the-counter and prescription medications can make your heart race or skip. Cold and allergy medicines containing decongestants are among the most common culprits. These work by constricting blood vessels in your nasal passages to reduce congestion, but they also stimulate the heart and blood vessels throughout your body. This can cause increased heart rate, elevated blood pressure, or skipped beats. Products with a “D” after the brand name (like Claritin-D or Zyrtec-D) typically contain a decongestant.
Asthma inhalers that open the airways can have a similar stimulant effect on the heart. Thyroid medications, if dosed too high, essentially create a state of overactive thyroid that speeds the heart. Some antidepressants, ADHD medications, and even certain herbal supplements can trigger palpitations as well. If your palpitations started around the same time as a new medication or dosage change, that timing is worth noting.
Medical Conditions Behind Palpitations
While most palpitations are benign, some reflect an underlying heart rhythm disorder. The two most common are atrial fibrillation and supraventricular tachycardia (SVT). Atrial fibrillation causes chaotic electrical signals in the upper chambers of the heart, leading to an irregular and often rapid heartbeat. It can come and go on its own or persist until treated, and it carries an increased risk of stroke. SVT causes a sudden, pounding heartbeat that starts and stops abruptly, sometimes lasting seconds, sometimes hours.
Outside the heart, thyroid problems are a major cause. An overactive thyroid floods your body with hormones that accelerate metabolism and heart rate. An underactive thyroid can also cause palpitations, though less commonly. Sleep apnea, where breathing repeatedly stops during sleep, stresses the heart and can trigger rhythm disturbances. Diabetes, high blood pressure, and COVID-19 infection have all been linked to arrhythmias as well.
Pregnancy and Hormonal Changes
Palpitations during pregnancy are remarkably common and usually harmless. Over the course of pregnancy, your blood volume increases by almost 50%. Your heart has to work significantly harder to pump all that extra blood through your body and to the growing fetus, so your resting heart rate naturally climbs. Many pregnant people notice their heart pounding or racing, particularly in the second and third trimesters.
Hormonal shifts during menstruation, perimenopause, and menopause can also trigger palpitations. Fluctuations in estrogen and progesterone affect the autonomic nervous system, which controls heart rate. These episodes tend to be temporary and tied to specific phases of the hormonal cycle.
How Palpitations Are Diagnosed
The challenge with diagnosing palpitations is that they often aren’t happening when you’re sitting in a doctor’s office. The first step is usually an electrocardiogram (EKG), a quick, painless test that measures your heart’s electrical activity in real time. It can reveal whether your heart is beating too fast, too slow, or irregularly, but only captures what’s happening during the few seconds you’re hooked up.
If the EKG looks normal but your symptoms continue, the next step is typically a Holter monitor, a portable device you wear for a day or more while going about your normal life. It continuously records your heart’s rhythm and can catch irregularities that a brief office EKG misses. For palpitations that happen less 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 marks that moment in the recording for your doctor to review.
Blood tests to check thyroid function, electrolyte levels, and blood counts are also standard. Sometimes an echocardiogram (an ultrasound of the heart) is ordered to look at the heart’s structure and valve function.
When Palpitations Are an Emergency
Most palpitations pass on their own and don’t require urgent care. But certain accompanying symptoms change the picture entirely. Call emergency services if your palpitations come with chest pain or tightness, difficulty breathing, or fainting or near-fainting. These combinations can indicate a serious arrhythmia, a heart attack, or another condition that needs immediate evaluation.
Palpitations that last several minutes without stopping, come with a heart rate well above 150 beats per minute, or happen alongside dizziness and lightheadedness also warrant prompt medical attention. A single skipped beat that resolves in seconds is almost always benign. A sustained episode that leaves you feeling faint is a different situation.