Feeling your heart beating is called a palpitation, and most of the time it’s harmless. Palpitations can show up as a pounding, fluttering, flip-flopping, or racing sensation in your chest, and sometimes you’ll notice them in your throat or neck too. Nearly everyone experiences them at some point, and the sensation usually reflects your body’s normal response to stress, exertion, or stimulants rather than a heart problem.
That said, certain patterns and accompanying symptoms do warrant attention. Understanding what’s behind the feeling can help you tell the difference between something your body is doing on purpose and something worth checking out.
Why You Suddenly Notice Your Heartbeat
Your heart beats roughly 100,000 times a day, and your brain filters most of those beats out of your awareness. You become conscious of them when something changes: your heart beats harder, faster, or out of its usual rhythm. The shift doesn’t have to be dramatic. Even a single stronger-than-normal beat can grab your attention.
Your nervous system plays a central role. When your body’s fight-or-flight response activates, it releases adrenaline, which binds to receptors on the heart and increases both the rate and force of each contraction. That’s why a sudden fright, a stressful email, or even standing up quickly can make your heartbeat feel obvious. The part of your brain responsible for generating awareness of your body’s internal state (located in a region called the insula) essentially turns up the volume on signals coming from your chest.
Some people are naturally more tuned in to their heartbeat than others. If you’re lying in a quiet room, especially on your left side, you may feel each beat simply because there’s nothing else competing for your attention. This is normal and doesn’t mean anything is wrong with your heart.
Common Harmless Triggers
Most palpitations trace back to everyday causes that temporarily change your heart rate or rhythm:
- Anxiety and stress. Your autonomic nervous system speeds up your heart rate as part of the fight-or-flight response. Some people feel palpitations even when their heart rhythm is completely normal, simply because anxiety heightens their awareness of bodily sensations.
- Exercise or physical exertion. Your heart rate naturally climbs to meet increased oxygen demand. Noticing a pounding heart during or right after a workout is expected.
- Dehydration and electrolyte shifts. Potassium, sodium, calcium, and magnesium all help conduct electrical signals through the heart. When levels dip (from sweating, skipping meals, or not drinking enough water), the heart’s rhythm can briefly stumble.
- Hormonal changes. Menstruation, pregnancy, and perimenopause can all trigger noticeable heartbeat changes.
- Poor sleep. Sleep deprivation raises baseline stress hormones, which in turn increase heart rate and force.
Caffeine is often blamed for palpitations, but research from a large study highlighted by Harvard Health found that healthy people who consumed multiple caffeinated products daily were no more likely to have palpitations than those who drank less. If you already have an irregular heart rhythm, caffeine may make it worse, but for most people it’s not the culprit.
Premature Beats: The “Skipped Beat” Feeling
That unsettling sensation of your heart skipping a beat or doing a somersault is usually caused by a premature contraction. These are extra beats that originate slightly earlier than expected, either in the upper chambers (premature atrial contractions) or the lower chambers (premature ventricular contractions). After the early beat, there’s a brief pause before the next normal beat, which tends to be more forceful than usual. It’s that stronger follow-up beat you actually feel, not the skip itself.
Premature beats are extremely common. Most people who have them don’t feel them at all, and in the absence of underlying heart disease, they’re considered benign. They can increase with caffeine, alcohol, lack of sleep, or stress, but they don’t typically require treatment.
Medical Conditions That Cause Palpitations
While most palpitations are harmless, some reflect an underlying condition that needs attention.
Thyroid Dysfunction
An overactive thyroid gland (hyperthyroidism) revs up your metabolism and can push your resting heart rate well above the normal range of 60 to 100 beats per minute. You might also notice weight loss, heat intolerance, and trembling hands alongside the palpitations. An underactive thyroid can also contribute to irregular rhythms, though it’s less commonly associated with the classic racing sensation.
Anemia
When your blood carries less oxygen than it should, your heart compensates by beating faster and harder. This can make your heartbeat feel unusually prominent, especially during mild exertion that wouldn’t normally faze you.
Heart Rhythm Disorders
True arrhythmias involve the heart’s electrical system misfiring in a more sustained way. Atrial fibrillation, the most common significant arrhythmia, produces a rapid, irregular rhythm that many people describe as a quivering or chaotic sensation in the chest. Other arrhythmias can cause sudden episodes of very fast heartbeats (over 150 beats per minute) that start and stop abruptly. These are distinct from the brief flutter of a premature beat because they persist for seconds, minutes, or longer.
The Anxiety-Palpitation Cycle
Anxiety and palpitations feed each other in a loop that can be difficult to break. Anxiety triggers the fight-or-flight response, which speeds up your heart. You notice the faster heartbeat, interpret it as something wrong, and that interpretation creates more anxiety, which keeps your heart rate elevated. Cleveland Clinic notes that some people feel palpitations during anxiety even when monitoring shows their heart rhythm is completely normal. The sensation is real, but it’s being generated by heightened body awareness rather than by a cardiac problem.
If you’ve had palpitations checked out and been told your heart is fine, this cycle is worth addressing directly. Breathing exercises, regular physical activity, and cognitive behavioral therapy can all reduce both the anxiety and the perception of abnormal heartbeats.
How Palpitations Are Evaluated
If your palpitations are frequent, prolonged, or come with other symptoms, a doctor will typically start with a physical exam (checking for signs like a swollen thyroid) and an electrocardiogram (ECG), which records your heart’s electrical activity through sticky patches on your chest. The test takes minutes and can reveal rhythm abnormalities happening in real time.
The challenge is that palpitations are often intermittent. If an ECG looks normal, you may be asked to wear a Holter monitor, a portable device that records your heart rhythm continuously for a day or more while you go about your life. For episodes that happen less than once a week, an event recorder works better. You wear it for up to 30 days and press a button whenever you feel symptoms, capturing the rhythm at that exact moment. In some cases, an echocardiogram (an ultrasound of the heart) is ordered to check the heart’s structure and blood flow.
Warning Signs That Need Urgent Attention
Most palpitations don’t require emergency care, but a few combinations of symptoms change the picture significantly. Palpitations paired with dizziness or lightheadedness warrant a trip to the emergency department. The same goes for palpitations accompanied by chest pain. A sudden collapse or loss of consciousness during palpitations is the most serious red flag and requires immediate emergency care.
A resting heart rate that regularly sits above 100 beats per minute, even when you’re calm, is also worth discussing with a healthcare provider. You can check this yourself by placing two fingers on the inside of your wrist and counting beats for 15 seconds, then multiplying by four.