Heart palpitations feel like your heart is skipping, fluttering, pounding, or racing, and they’re one of the most common reasons people worry about their heart. In the vast majority of cases, the sensation comes from premature heartbeats, which are almost always harmless. But several factors, from your morning coffee to low potassium levels, can trigger them or make them worse.
What Actually Happens During a Palpitation
Most palpitations are caused by premature heartbeats. These are extra beats that fire slightly earlier than your heart’s normal rhythm. They can start in the upper chambers of your heart (premature atrial contractions, or PACs) or the lower chambers (premature ventricular contractions, or PVCs). Nearly everyone has them. Most people just don’t notice.
What you feel isn’t the extra beat itself. After the premature beat fires, there’s a brief pause before your heart resets to its normal rhythm. That next normal beat is more forceful than usual because the heart had a split second longer to fill with blood. The “thump” or “flip” sensation you notice is that stronger-than-usual beat. Some people feel a fluttering sensation instead, especially when premature beats happen in clusters.
Common Triggers
Stimulants are the most frequent culprit. Caffeine, nicotine, and certain decongestants can all increase the electrical irritability of your heart tissue, making premature beats more likely. Caffeine sensitivity varies widely from person to person. Some people tolerate several cups of coffee without issue, while others notice palpitations after a single cup. If you’re trying to identify your trigger, cutting caffeine for a week or two is a reasonable starting point.
Alcohol is another well-known trigger. Even moderate drinking can provoke irregular rhythms in some people, and binge drinking is strongly associated with episodes of rapid, chaotic heart rhythms. Dehydration and poor sleep both lower the threshold for palpitations as well. Intense exercise, especially if you’re not well hydrated, can also set them off.
Stress and anxiety deserve special attention because they create a feedback loop. Stress hormones make your heart more reactive, which produces palpitations, which makes you more anxious, which releases more stress hormones. Many people who present to emergency rooms with palpitations have anxiety as either the primary cause or a major amplifier.
Anxiety-Related Palpitations vs. Heart Problems
Panic attacks can produce intense palpitations along with chest tightness, shortness of breath, and a feeling of doom. These episodes start suddenly and typically peak within minutes. The key difference between a panic attack and a cardiac event is how symptoms behave over time. Panic attack symptoms usually fade within 20 to 30 minutes on their own. Symptoms from a genuine heart problem tend to start more gradually, intensify, and persist until treated.
If you notice that your palpitations come on during moments of stress, are accompanied by rapid shallow breathing, and resolve once you calm down, anxiety is likely involved. That doesn’t mean the sensation isn’t real or that you should ignore it. It means the solution may involve managing the anxiety rather than treating your heart directly.
Low Potassium and Other Nutritional Causes
Your heart’s electrical system depends on a precise balance of minerals, especially potassium and magnesium. Normal potassium levels range from 3.5 to 5.2 mEq/L. When levels drop below 3.5, your heart becomes electrically irritable, and abnormal rhythms become more likely. Below 3.0 is considered severe and can cause dangerous arrhythmias.
Low magnesium often accompanies low potassium and can make it harder for your body to restore potassium to normal levels. Common causes of depletion include heavy sweating, chronic diarrhea, excessive alcohol use, and certain medications like diuretics. If your palpitations are frequent and you have any of these risk factors, a simple blood test can check your levels.
Medical Conditions That Cause Palpitations
While most palpitations are benign, some are caused by arrhythmias that need treatment. Supraventricular tachycardia (SVT) is one of the more common ones. It causes sudden episodes where your heart races at 150 beats per minute or more, then stops just as abruptly. Atrial fibrillation, which becomes more common with age, causes an irregular and often rapid heartbeat that can last hours or days. Thyroid disorders, particularly an overactive thyroid, are another medical cause. Anemia, where your blood carries less oxygen than normal, forces your heart to beat faster and harder to compensate, which you may feel as pounding or racing.
What You Can Try at Home
If you feel a sudden racing heartbeat, vagal maneuvers can sometimes reset your rhythm. These techniques stimulate the vagus nerve, which slows your heart rate. They work best for SVT and have a 20% to 40% success rate for converting a fast rhythm back to normal.
- Valsalva maneuver: Lie on your back, take a deep breath, then bear down as if you’re trying to exhale through a blocked straw. Keep your nose and mouth closed and hold for 10 to 30 seconds.
- Diving reflex: Take several deep breaths, hold one, and submerge your face in a bowl of ice water for as long as you can tolerate. Alternatively, press a bag of ice or a cold wet towel against your face.
- Applied abdominal pressure: Lie on your back, curl your lower body toward your face so your feet pass over your head, take a breath, and strain for 20 to 30 seconds.
For occasional benign palpitations that don’t involve sustained rapid rates, simpler strategies help. Slow, deep breathing for a few minutes can interrupt the stress-hormone cycle. Reducing caffeine and alcohol, staying hydrated, and getting consistent sleep address the most common everyday triggers.
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. A standard electrocardiogram (ECG) captures only about 10 seconds of your heart’s activity. If your rhythm is normal during those seconds, it won’t catch the problem.
For that reason, doctors frequently use Holter monitors, which are portable devices that record your heart rhythm continuously for 24 to 48 hours. A recent study of emergency department patients found that Holter monitoring produced diagnostically useful results in about 68% of cases, with significant arrhythmias detected in 37% of patients monitored. There was no meaningful difference in detection rates between 24-hour and 48-hour monitoring periods.
If your palpitations happen less frequently than every day or two, an event monitor or a patch monitor worn for one to four weeks may be more useful. These devices let you press a button when you feel symptoms, so the recording captures the exact moment you’re experiencing the palpitation.
When Palpitations Need Urgent Attention
Most palpitations are not emergencies. But certain combinations of symptoms suggest something more serious is happening. Seek emergency care if your palpitations are accompanied by any of the following: sudden collapse or loss of consciousness, significant dizziness or lightheadedness, chest pain or pressure that doesn’t resolve within a few minutes, or shortness of breath that feels out of proportion to your activity level. A racing heart that starts suddenly and doesn’t slow down after several minutes, especially if you feel faint, also warrants immediate evaluation.