Key takeaways:
The most common atrial fibrillation (AFib) symptom is heart palpitations. These usually feel like a fast, irregular heartbeat that may last for hours or longer.
Some people with AFib won’t notice their heart racing. Instead, they might feel dizzy, lightheaded, short of breath, or unusually tired.
If you’re experiencing symptoms of AFib, it’s important to see a healthcare professional. Treatment reduces your risk for stroke and heart failure.
Atrial fibrillation (AFib) is a common heart rhythm condition that causes an irregular heartbeat. Often, AFib also makes your heart beat too fast. Many people have obvious symptoms when they’re in AFib, like palpitations that don’t stop. But others may feel very little. Sometimes, AFib symptoms can be mistaken for something else.
Knowing what AFib can feel like is important. That’s because recognizing it early means that you can get the treatment you need to lower your risk of serious problems, including stroke and heart failure.
What is atrial fibrillation?
AFib is an arrhythmia. This means it causes your heart to beat differently than normal. To understand exactly how AFib affects heart rhythm, it helps to know what a normal heart rhythm looks like.
The heart has a natural pacemaker called the sinus node. It sits at the top of your heart. When everything is working normally, the sinus node sends steady signals that tell your heart when to beat.
In AFib, your heart’s pacemaker no longer controls the heartbeat. Instead, the upper chambers of your heart, called the atria, send fast, unorganized electrical signals. This makes the atria quiver or shake instead of squeezing normally. Some of these signals also reach the lower chambers of your heart. This causes your heartbeat to become irregular and often faster than it should be.
AFib affects millions of people, including more than 1 in 8 people over the age of 80. It’s more common in people over 65, but younger people can also get AFib.
What are the symptoms of AFib?
One of the most common symptoms of AFib is palpitations. These can feel like a fast or fluttering heartbeat. You may feel them in your chest, but they can also be felt in your throat, neck, or even your ears. These symptoms may last a few minutes, but they often continue for hours or even days. Without treatment, symptoms of AFib can sometimes last much longer or keep coming back.
AFib can also cause other symptoms, including:
Dizziness
Lightheadedness
Shortness of breath
Chest pain
Fatigue
Weakness
Many people have paroxysmal AFib. This means that it comes and goes. Some people feel every episode. Others may not notice when they’re in AFib. Your healthcare team can give you personalized advice about what symptoms to watch for, what to do if AFib happens, and when to seek help.
Are the symptoms of AFib in women different?
Compared to men, women with AFib often have stronger palpitations and more lightheadedness. AFib can also affect a woman’s quality of life more.
Some women may also have less common symptoms, like stomach upset, diarrhea, or extreme fatigue. This can make it easier for women to mistake AFib for another health condition or even stress. As a result, it isn’t surprising that it often takes longer for women to get diagnosed with AFib compared to men. Studies also show that women’s symptoms are sometimes overlooked or not taken seriously by healthcare professionals or even by a partner. This can delay getting the right diagnosis.
What are the most common triggers of AFib?
If you have AFib, episodes can happen without any clear reason. But there are some important triggers to be aware of. These include:
Stress
Heavy exertion
Fatigue
Infections anywhere in your body, which can put extra stress on your heart
Energy drinks, which often combine high levels of caffeine with other stimulants
Dehydration
Heavy meals, because a very full stomach may stimulate the nerves that control your heart’s rhythm
For some people, coffee or tea may trigger AFib symptoms. Although recent research suggests that many people with AFib can safely have one or even a few cups a day without problems.
Until more is known, it’s a good idea to limit coffee or tea to no more than 3 cups per day. You may also want to avoid caffeinated sodas and energy drinks, especially if caffeine seems to trigger your symptoms.
When should you see a doctor about AFib symptoms?
If you think you might have AFib, it’s important to see a healthcare professional to get the problem checked out.
Some symptoms mean you should get emergency care right away. These include:
A heart rate that stays over 120 beats per minute
Chest pain
Shortness of breath
Dizziness or lightheadedness
Any signs of stroke, like numbness, weakness, or difficulty speaking
Frequently asked questions
By itself, AFib isn’t usually life-threatening. It can be managed with medications or a procedure called an ablation. But if atrial fibrillation isn’t treated, it can raise your risk of stroke by up to five times. It can also raise your risk for heart failure, especially if your heart rate stays too fast for 24 hours or more. If you have AFib, or think you might, it’s important to get medical care.
When AFib is managed well with the right treatment, most people can continue their usual daily activities with few limitations. If your resting heart rate is too fast (more than 110 beats per minute), avoid moderate to heavy physical activity until it’s under control. You should also take it easy if you’re feeling unwell. In these situations, it’s important to seek medical care.
Atrial flutter and AFib both happen when abnormal electrical signals in the upper chambers of your heart take over the normal rhythm. The main difference is that atrial flutter has a more regular rhythm. In atrial flutter, the upper chambers can beat as fast as 300 times per minute. Not all of these beats reach the lower chambers, so your pulse may feel normal or only slightly fast. Like AFib, atrial flutter can come and go. It can also increase your risk for stroke.
By itself, AFib isn’t usually life-threatening. It can be managed with medications or a procedure called an ablation. But if atrial fibrillation isn’t treated, it can raise your risk of stroke by up to five times. It can also raise your risk for heart failure, especially if your heart rate stays too fast for 24 hours or more. If you have AFib, or think you might, it’s important to get medical care.
When AFib is managed well with the right treatment, most people can continue their usual daily activities with few limitations. If your resting heart rate is too fast (more than 110 beats per minute), avoid moderate to heavy physical activity until it’s under control. You should also take it easy if you’re feeling unwell. In these situations, it’s important to seek medical care.
Atrial flutter and AFib both happen when abnormal electrical signals in the upper chambers of your heart take over the normal rhythm. The main difference is that atrial flutter has a more regular rhythm. In atrial flutter, the upper chambers can beat as fast as 300 times per minute. Not all of these beats reach the lower chambers, so your pulse may feel normal or only slightly fast. Like AFib, atrial flutter can come and go. It can also increase your risk for stroke.
The bottom line
Atrial fibrillation (AFib) often feels like a fast, irregular heartbeat. If you’re in AFib, you might notice a fluttering sensation in your chest. But some people have less obvious symptoms. They may feel dizzy, lightheaded, short of breath, or unusually tired. If you’re experiencing any of these symptoms, it’s important to get the problem checked out with your healthcare professional. Chest pain or stroke symptoms need emergency evaluation. AFib can usually be managed successfully, even if it doesn’t go away completely. With the right treatment, you can get back to doing the things you enjoy.
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References
Andrade, J. G., et al. (2025). Atrial fibrillation in the Americas. The Lancet Regional Health - Americas.
Bodar, V., et al. (2019). Coffee consumption and risk of atrial fibrillation in the physicians’ health study. Journal of the American Heart Association.
Hansson, A., et al. (2004). Arrhythmia-provoking factors and symptoms at the onset of paroxysmal atrial fibrillation: A study based on interviews with 100 patients seeking hospital assistance. BMC Cardiovascular Disorders.
Mattioli, V. (2014). Beverages of daily life: Impact of caffeine on atrial fibrillation. Journal of Atrial Fibrillation.
Piccini, J. P., et al. (2016). Differences in clinical and functional outcomes of atrial fibrillation in women and men: Two-year results from the ORBIT-AF registry. JAMA Cardiology.
Rattanawong, P., et al. (2020). Drug therapy for vagally-mediated atrial fibrillation and sympatho-vagal balance in the genesis of atrial fibrillation: A review of the current literature. Journal of Atrial Fibrillation.
Sun, Y., et al. (2024). Sweetened beverages, genetic susceptibility, and incident atrial fibrillation: A prospective cohort study. Circulation: Arrhythmia and Electrophysiology.
Walfridsson, U., et al. (2019). Gender and age differences in symptoms and health-related quality of life in patients with atrial fibrillation referred for catheter ablation. Pacing and Clinical Electrophysiology: PACE.
Wilson, R. E., et al. (2021). Gender and the symptom experience before an atrial fibrillation diagnosis. Western Journal of Nursing Research.
Wong, C. X., et al. (20205). Caffeinated coffee consumption or abstinence to reduce atrial fibrillation. The DECAF randomized control trial. JAMA.
