Heart palpitations happen when you become aware of your heartbeat in a way that feels unusual, whether it’s racing, fluttering, pounding, or skipping a beat. They’re extremely common. Palpitations account for 16% of all visits to primary care doctors and are the second most common reason people see a cardiologist. In most cases, the cause is not dangerous, but understanding the triggers helps you figure out what’s going on in your body.
What’s Actually Happening in Your Heart
Your heart has a built-in electrical system that coordinates each beat. Normally, an electrical signal starts in a specific area at the top of the heart and travels down through a predictable pathway, telling each chamber when to contract. Palpitations often occur when a stray electrical signal fires from somewhere outside that normal pathway, producing what’s called an ectopic beat, essentially an extra or premature heartbeat.
These premature beats are usually followed by a brief pause as the heart resets its rhythm. That pause, and the stronger-than-usual beat that follows, is what most people feel as a “skip” or a “thud.” In a healthy heart, these extra beats are almost always harmless. They can happen dozens or even hundreds of times a day without you noticing most of them.
Stress and Anxiety
Psychological causes are the single most common reason for palpitations, accounting for roughly 31% of all cases evaluated in primary care. When you feel anxious or stressed, your body activates its fight-or-flight response through the autonomic nervous system. This floods your bloodstream with adrenaline, which directly speeds up your heart rate and makes each beat feel more forceful. The result is a pounding or racing sensation that can feel alarming, which in turn creates more anxiety and more adrenaline.
During a panic attack, this cycle intensifies rapidly. Your heart rate can spike to well over 100 beats per minute within seconds, and you may also feel short of breath, dizzy, or lightheaded. These symptoms can mimic a heart problem so convincingly that many people end up in the emergency room. If you’ve been evaluated and told your heart is structurally normal, the palpitations you feel during stressful moments are almost certainly this adrenaline-driven response.
Caffeine, Alcohol, and Nicotine
Caffeine is a stimulant that raises your heart rate regardless of whether it comes from coffee, tea, energy drinks, soda, or chocolate. That said, one study found that caffeine from coffee, tea, and chocolate is unlikely to cause palpitations in people with healthy hearts. The effect is more pronounced if you’re sensitive to stimulants or consume significantly more than your usual amount.
Alcohol is a different story. Drinking more than usual, or binge drinking in particular, can trigger a fluttering or racing heartbeat. Some people notice it even after small amounts. Nicotine, whether from cigarettes or nicotine replacement products like patches and gum, raises blood pressure and speeds up heart rate directly. If you’ve recently started or increased any of these substances and notice new palpitations, the connection is likely not a coincidence.
Recreational drugs carry far more serious risks. Cocaine raises blood pressure, accelerates heart rate, and can damage heart muscle directly. Amphetamines stimulate the nervous system aggressively, ramping up your heartbeat. Ecstasy triggers a surge of norepinephrine, a chemical that forces the heart to beat faster.
Medications That Affect Heart Rhythm
Several common medication categories can cause palpitations as a side effect. Asthma inhalers that contain airway-opening drugs are among the most frequent culprits, because the same mechanism that relaxes airways also stimulates the heart. Decongestants found in cold and sinus medications (the kind you sometimes have to ask a pharmacist for) have a similar stimulant effect.
Some antidepressants and antipsychotic medications can alter heart rhythm. So can certain anti-inflammatory painkillers. If palpitations started around the time you began a new medication, that timing is worth mentioning to whoever prescribed it. Don’t stop a medication on your own, but do flag the symptom.
Hormonal Shifts
Fluctuating hormone levels are one of the most common causes of palpitations that catch women off guard. Big surges in hormones during pregnancy, in the days before a period, or during menopause can all make palpitations more likely. During pregnancy, blood volume increases significantly and the heart works harder to pump it, which can produce a racing or pounding sensation even at rest. During perimenopause and menopause, unpredictable hormonal swings can trigger episodes that feel identical to anxiety-related palpitations but occur without any obvious emotional trigger.
Low Electrolytes
Your heart’s electrical system depends on minerals like potassium and magnesium to function properly. When levels of either drop too low, the electrical signals that coordinate your heartbeat become unstable, leading to skipped beats, fluttering, or an irregular rhythm. Potassium deficiency is particularly common in people who take certain blood pressure medications (water pills), who have been vomiting or experiencing diarrhea, or who simply don’t eat enough potassium-rich foods like bananas, potatoes, and leafy greens. Low magnesium makes potassium deficiency worse, because your body has trouble holding onto potassium when magnesium is depleted.
Dehydration from exercise, heat, or illness can temporarily shift electrolyte levels enough to cause palpitations. If you notice episodes after heavy sweating or during a stomach illness, low electrolytes are a likely explanation.
Thyroid Problems and Other Medical Conditions
An overactive thyroid gland produces excess hormones that affect every cell in your body, including heart cells. The result is a metabolism running too fast: weight loss, hand tremors, heat intolerance, and a rapid or irregular heartbeat. If palpitations come alongside unexplained weight loss, feeling unusually warm, or nervousness that doesn’t match your circumstances, a thyroid blood test can confirm or rule out hyperthyroidism quickly.
Anemia, where your blood carries fewer red blood cells than normal, forces the heart to beat faster to deliver enough oxygen to your tissues. This can feel like a racing or pounding heart, especially during physical activity. Heavy periods, iron-poor diets, and chronic conditions can all lead to anemia.
When Palpitations Signal Something Serious
Most palpitations are benign. Of all cases evaluated in primary care, only about 3% involve structural heart disease and 2% involve a dangerous rhythm called ventricular tachycardia. But certain accompanying symptoms change the picture. Palpitations combined with sudden collapse or loss of consciousness require immediate emergency care. A racing heart paired with dizziness or lightheadedness is another reason to go to the emergency department right away. Chest pain alongside palpitations also warrants urgent evaluation.
Atrial fibrillation, an irregular rhythm originating in the upper chambers of the heart, accounts for about 16% of palpitations seen in primary care. It often feels like a quivering or chaotic fluttering rather than a simple skipped beat. It isn’t immediately life-threatening in most cases, but it does increase the long-term risk of stroke and needs medical management.
How Palpitations Are Evaluated
The challenge with diagnosing palpitations is that they often come and go, so your heart may be beating perfectly normally during your appointment. The starting point is a standard 12-lead electrocardiogram (ECG), which records your heart’s electrical activity for about 10 seconds. If that’s normal but your symptoms are frequent, your doctor may have you wear a portable monitor. These range from adhesive patches worn for a few days to loop recorders that stay on for weeks, capturing your heart rhythm during daily life so an episode can be caught and analyzed. Smartwatches and handheld ECG devices can also record a tracing during symptoms, giving your doctor useful data.
Blood tests typically check thyroid function, electrolyte levels, and red blood cell counts to rule out the treatable medical causes. An echocardiogram, which uses ultrasound to look at the heart’s structure, may be ordered if there’s any suspicion of a structural problem. For palpitations that are infrequent but concerning, implantable monitors placed just under the skin offer the highest sensitivity for catching irregular rhythms over months of continuous recording.