That fluttering, skipping, or “missed beat” sensation in your chest is almost always caused by an extra heartbeat firing slightly earlier than it should. Doctors call these premature contractions, and they’re remarkably common. A population-based study of healthy adults aged 25 to 41 found that 69% had at least one of these extra beats during a single day of heart monitoring. Most people experience them without ever knowing it, and only notice when the sensation becomes strong enough to feel.
What Actually Happens in Your Heart
Your heart has a built-in pacemaker that sends an electrical signal at regular intervals, triggering each heartbeat. A “skipped beat” happens when a different part of the heart fires off its own electrical signal too early, before the pacemaker’s next scheduled beat. This premature beat doesn’t pump as much blood because the heart hasn’t had time to fill completely. Then there’s a slightly longer pause before the next normal beat, and that next beat is often stronger than usual because the heart has had extra time to fill with blood. That stronger thump, or the pause before it, is what you actually feel.
These early beats can originate in two places. When they come from the upper chambers of the heart, they’re called premature atrial contractions. When they come from the lower chambers, they’re premature ventricular contractions. Both produce a similar skipping or fluttering sensation. The lower-chamber type is more common and tends to feel more noticeable because it disrupts the heart’s pumping more forcefully. In the vast majority of people, neither type is dangerous.
Why They Happen
The most common triggers are everyday substances and states your body encounters regularly. Caffeine increases calcium levels inside heart muscle cells, which can make those cells more electrically excitable and prone to firing on their own. It also boosts adrenaline-like hormones and blocks certain receptors that normally keep heart rate steady. This combination of effects is why a strong cup of coffee sometimes triggers that familiar flutter.
Alcohol is another well-known trigger, particularly for irregular rhythms originating in the upper chambers. Nicotine, dehydration, and poor sleep can all increase the frequency of premature beats as well. Stress and anxiety raise adrenaline levels, which makes heart cells more reactive. Even a large meal or bending over in certain positions can trigger them in some people.
Electrolyte imbalances play a significant role. Magnesium and potassium work together to maintain the electrical stability of heart cells. When magnesium is low, cells can’t properly regulate potassium levels across their membranes. This disrupts the electrical charge that keeps each heartbeat firing in an orderly sequence, making premature beats more likely. People who sweat heavily, take certain medications, or don’t get enough of these minerals through their diet are more susceptible.
How to Tell if They’re Harmless
Isolated skipped beats that come and go, especially ones you can link to caffeine, poor sleep, or stress, are almost always benign. They may feel alarming, but the sensation itself is not a sign of heart damage. Many people go through phases where they notice them frequently for days or weeks, then they disappear on their own.
The frequency of premature beats matters more than whether they happen at all. Research from the American Heart Association defines a “high burden” as more than 10,000 extra beats per day, or more than 10% of all heartbeats in a 24-hour period. To put that in perspective, the median number of premature beats in a healthy population study was just 2 per day. At very high levels, particularly when premature beats account for more than 25% of all heartbeats, there is an increased risk that the heart muscle can weaken over time. This is uncommon and develops gradually, not suddenly.
When Skipped Beats Need Attention
Certain accompanying symptoms change the picture significantly. Skipped beats paired with any of the following warrant prompt medical evaluation:
- Fainting or near-fainting, especially if you’ve injured yourself during an episode
- Chest pain or shortness of breath occurring alongside the palpitations
- A resting heart rate above 120 or below 45 beats per minute
- A new, sustained irregular rhythm that doesn’t resolve on its own
- A family history of sudden cardiac death
- Known underlying heart disease
The key distinction is between an occasional extra beat and a sustained abnormal rhythm. A single skip or flutter that lasts a moment is very different from minutes of rapid, irregular pounding. The latter may indicate a rhythm problem that needs treatment.
How Skipped Beats Are Diagnosed
If your doctor wants to investigate further, the most common tool is a Holter monitor, a small device you wear for 24 to 48 hours that continuously records your heart’s electrical activity. This captures every premature beat and measures how often they occur relative to your total heartbeats. Some people wear an event monitor for up to 30 days if their symptoms are infrequent. A standard electrocardiogram (EKG) in the office captures only a brief snapshot, so it may miss occasional extra beats entirely.
Blood tests for electrolytes, thyroid function, and sometimes anemia round out the evaluation. An overactive thyroid is a well-known but often overlooked cause of frequent palpitations.
Reducing Skipped Beats
For most people, lifestyle changes are enough. Cutting back on caffeine, reducing alcohol intake, improving sleep, and managing stress often reduce the frequency of premature beats noticeably within a few weeks. Staying well hydrated and eating foods rich in potassium and magnesium (bananas, leafy greens, nuts, avocados) supports the electrical stability of heart cells.
Regular exercise generally reduces premature beats over time, though some people notice them more during or immediately after a workout. This is typically harmless, but if exercise consistently triggers prolonged palpitations or lightheadedness, it’s worth mentioning to a doctor.
When lifestyle changes aren’t enough and symptoms are frequent or bothersome, beta-blockers are the most common first-line medication. These drugs reduce adrenaline’s effect on the heart, slowing the heart rate slightly and making the muscle less prone to firing extra beats. They’re taken as daily pills, often once or twice a day depending on the specific formulation. Most people tolerate them well, though fatigue and cold hands are common side effects. For the small number of people with very high premature beat counts that risk weakening the heart, a specialized procedure called catheter ablation can target and disable the specific spot generating the extra signals.
Why You Feel Them More at Some Times
Many people notice skipped beats most when lying in bed at night or sitting quietly. This isn’t because they’re happening more often. In a quiet environment with fewer distractions, you’re simply more aware of your heartbeat. Lying on your left side can also make the sensation more pronounced because the heart sits closer to the chest wall in that position.
Anxiety creates a feedback loop that makes this worse. You feel a skip, which triggers a spike of adrenaline, which makes more skips likely, which increases your anxiety further. Understanding that the sensation is almost always a normal electrical hiccup, not a sign of cardiac danger, can help break that cycle. People who learn what premature beats actually are often report that the symptoms bother them significantly less, even before any medical treatment.