Sometimes, even when you're still, your heart might suddenly race or feel like it's dropping. While it might get better after a moment, if you also feel dizzy or your vision blurs, your worries can grow.
This kind of palpitation is called 심계항진 (palpitations). The cause could be the heart itself, anemia, thyroid issues, or simply lifestyle habits. If you experience new symptoms repeatedly, you should first consider the situations in which they occur.
When the Rhythm is Disturbed
The heart repeatedly contracts and relaxes in a steady rhythm. When this rhythm becomes too fast, too slow, or irregular, it's called 부정맥 (arrhythmia).
This can cause your heart to race, feel like it skips a beat, or a sudden jolt in your chest. If the blood flow to your brain temporarily decreases at this time, you might feel dizzy or your vision might darken. However, not all palpitations are arrhythmias, so you should consider the situation and your pulse together.
Causes Outside the Heart
If you have 빈혈 (anemia), your heart beats faster to compensate for the lack of oxygen. If you get tired easily, become breathless with little movement, and your face is pale, you can check this with a blood test.
When thyroid hormones are excessively produced, your pulse also quickens. If you are particularly sensitive to heat, sweat more, have shaky hands, and lose weight despite eating normally, your thyroid function should be checked.
First, Look at Your Lifestyle
Palpitations can also occur if you've increased your coffee or energy drink intake, or on days when you haven't slept well. Caffeine directly increases heart rate, and excessive alcohol consumption and smoking also have an impact.
The same symptoms can appear when your autonomic nervous system is on edge due to stress or tension. Recalling what has changed around the time your symptoms started can provide a clue.
How to Check
Your pulse and blood pressure will be checked, and you should note when the symptoms started and how long they last. If necessary, an electrocardiogram (ECG) can check the heart's electrical activity and rhythm. If anemia or thyroid issues are suspected, a blood test will be added.
However, if palpitations are accompanied by crushing chest pain, severe shortness of breath, or if you feel like you might lose consciousness, it could be an emergency, and you should seek immediate medical attention.
Reviewed by: Dr. Kim Seonhoo · Gastroenterology Subspecialist, Digestive Endoscopy Specialist Last Reviewed: 2026-09-02
This article is intended to provide general health information, and the cause and necessary tests may vary depending on individual conditions. If symptoms persist, please consult with medical staff for diagnosis.