Tachycardia means your heart is beating faster than normal while you’re at rest. For adults, the threshold is a resting heart rate above 100 beats per minute. A healthy resting heart rate typically falls between 60 and 100 beats per minute, so tachycardia begins where that normal range ends. It can be a temporary response to something like exercise, stress, or caffeine, or it can signal an underlying heart or health problem that needs attention.
Why Your Heart Rate Matters
Your heart pumps blood in a coordinated rhythm controlled by electrical signals. These signals tell the upper chambers (atria) to squeeze first, then the lower chambers (ventricles), pushing blood out to the lungs and the rest of the body. Tachycardia happens when something disrupts those electrical signals or forces the heart to work harder than it should at rest.
A fast heart rate during exercise or a moment of fear is completely normal. The concern starts when your heart races while you’re sitting still, lying down, or doing light activity, and it happens repeatedly or lasts a long time. When the heart beats too fast, it doesn’t fill with enough blood between beats, which means less oxygen-rich blood reaches your organs. Over time, this extra workload can weaken the heart muscle.
Types of Tachycardia
Tachycardia is classified by where in the heart the abnormal electrical activity starts.
Supraventricular tachycardia (SVT) originates in the upper chambers. One common form, paroxysmal supraventricular tachycardia (PSVT), causes sudden extra heartbeats due to faulty electrical signals that begin in the atria and travel down to the lower chambers. Episodes often start and stop abruptly. Many people describe them as a sudden “flip-flop” in the chest that resolves on its own within minutes, though some episodes last longer.
Sinus tachycardia is the most straightforward type. The heart’s natural pacemaker (the sinus node) simply fires faster than usual. This is the kind you get from fever, dehydration, anxiety, or too much caffeine. It’s often a symptom of something else rather than a heart problem itself.
Ventricular tachycardia starts in the lower chambers and is generally more serious. The ventricles are responsible for pumping blood to your entire body, so when their rhythm goes haywire, the consequences can be severe. A few seconds of ventricular tachycardia may cause no harm, but sustained episodes can deteriorate into ventricular fibrillation, where the heart quivers instead of pumping. Blood pressure drops dramatically, breathing and pulse stop, and without immediate CPR, it’s fatal.
Common Causes and Triggers
Tachycardia has a wide range of triggers. Some are everyday and harmless, while others point to a medical condition that needs treatment.
- Lifestyle triggers: caffeine, alcohol, nicotine, stimulant drugs, dehydration, and lack of sleep can all push your resting heart rate above 100.
- Physical stress: fever, anemia (low red blood cell count), significant blood loss, and pain raise heart rate because the body is trying to compensate.
- Hormonal conditions: an overactive thyroid gland speeds up metabolism and heart rate together.
- Heart-related causes: damage from a previous heart attack, heart valve problems, or heart failure can create abnormal electrical pathways that trigger tachycardia.
- Emotional stress and anxiety: the fight-or-flight response floods the body with adrenaline, which directly speeds up the heart.
In some people, no clear cause is ever found. The heart’s electrical system simply misfires occasionally, producing short bursts of rapid heartbeat that resolve on their own.
What Tachycardia Feels Like
Some people with tachycardia have no symptoms at all and only discover it during a routine checkup. When symptoms do appear, they can range from mildly annoying to frightening. The most common sensation is palpitations: a racing, pounding, or fluttering feeling in the chest. You might describe it as your heart “skipping” or doing a flip.
Other symptoms include dizziness, lightheadedness, shortness of breath (especially with activities that didn’t used to wind you, like climbing stairs), fatigue, chest pain, weakness, and in more serious cases, fainting or near-fainting. These symptoms reflect the fact that your organs aren’t getting enough blood flow when the heart beats too fast to fill properly.
If you experience trouble breathing, chest pain, a pounding heart that won’t slow down, or feel faint, those are signs that need immediate medical attention. If someone near you collapses and has no pulse, call emergency services and start CPR right away.
How Tachycardia Is Diagnosed
The first and simplest test is an electrocardiogram (EKG), which records your heart’s electrical activity through sticky patches placed on your chest. It takes only a few minutes and can reveal whether your heart rhythm is abnormal and where the problem originates.
The tricky part is that tachycardia often comes and goes. If your heart happens to be beating normally during the EKG, the test won’t catch anything. That’s where a Holter monitor comes in. It’s a small, wearable device that continuously records your heartbeat for 24 to 48 hours (or longer) while you go about your daily life. This gives a much better picture of what’s happening over time.
Beyond rhythm monitoring, your doctor may order additional tests depending on what they suspect:
- Echocardiogram: uses sound waves to create a live image of your heart, showing how blood flows through the chambers and valves.
- Stress test: monitors your heart while you walk on a treadmill or ride a stationary bike, since exercise can trigger or worsen certain types of tachycardia.
- Electrophysiology (EP) study: a more specialized test that maps exactly where in the heart the faulty electrical signals originate. This is typically reserved for specific types of tachycardia when a procedure to fix the problem is being considered.
- Cardiac MRI or CT scan: detailed imaging used mainly when ventricular tachycardia is suspected, to look for structural problems in the heart muscle.
Treatment Options
Treatment depends entirely on the type and cause. Sinus tachycardia from caffeine, stress, or fever often doesn’t need any cardiac treatment at all. Addressing the underlying trigger, whether that means cutting back on stimulants, treating an infection, or managing an overactive thyroid, brings the heart rate back to normal.
For SVT, a technique called a vagal maneuver can sometimes break an episode in real time. This involves actions like bearing down as if you’re having a bowel movement, coughing, or placing a cold, wet towel on your face. These stimulate the vagus nerve, which helps slow the heart. If that doesn’t work, medications that slow the heart’s electrical conduction are the next step.
When tachycardia recurs frequently or is caused by an identifiable electrical short circuit in the heart, a procedure called catheter ablation may be recommended. A thin, flexible tube is guided through a blood vessel to the heart, where it delivers targeted energy to destroy the tiny area of tissue responsible for the abnormal signals. Success rates for ablation are high for many types of SVT, and it can be a permanent fix.
Ventricular tachycardia is treated more aggressively because of its potential to become life-threatening. Some people receive an implantable defibrillator, a small device placed under the skin that monitors the heart and delivers a corrective shock if a dangerous rhythm is detected.
Living With Tachycardia
For many people, tachycardia is manageable and not dangerous. Knowing your triggers makes a real difference. Tracking your episodes, including what you were doing, eating, or drinking beforehand, helps you and your doctor identify patterns. Reducing caffeine, staying well hydrated, getting enough sleep, and managing stress are practical steps that lower the frequency of episodes for a lot of people.
If you’ve been diagnosed, wearing a fitness tracker or smartwatch that monitors heart rate can be a useful tool for spotting episodes you might not feel. It also gives you data to share at appointments, which helps your doctor decide whether your current approach is working or needs adjustment.