Atrial fibrillation (AFib) risk factors: what raises the risk and what you can change

What AFib is

Atrial fibrillation, also called AFib or AF, is one of the most common types of irregular heart rhythm. It affects more than 2 million adults in the United States (NHLBI). In AFib the heart beats irregularly and sometimes much faster than normal, and the upper and lower chambers do not work together as they should, so the lower chambers do not fill completely or pump enough blood (NHLBI).

AFib is most often caused by changes to the heart's tissue or to the electrical signals that help the heart beat. Most often this damage comes from other conditions such as high blood pressure and coronary heart disease (NHLBI). Sometimes AFib happens for no obvious reason (NHLBI), and sometimes the cause is unknown (MedlinePlus).

Risk factors that raise the risk

Anyone can develop AFib, but these things raise the risk (NHLBI) (MedlinePlus):

• Age. The risk goes up as you get older, especially over age 65. AFib is rare in children (NHLBI). The US Preventive Services Task Force puts it at under 0.2% of adults younger than 55 and about 10% of those 85 or older, and notes that it is more common in men than in women (USPSTF 2022).
• Family history and genes. If someone in your family has had AFib, your risk is higher too. Scientists have found some gene changes that raise the risk (NHLBI).
• High blood pressure (NHLBI).
• Heart conditions: coronary heart disease, heart failure, heart valve disease and sick sinus syndrome (a problem with the heart's electrical signals) (NHLBI). MedlinePlus also names congenital heart defects (MedlinePlus).
• Hyperthyroidism (an overactive thyroid) (NHLBI).
• Overweight and obesity (NHLBI).
• Diabetes (NHLBI).
• Sleep apnea and other sleep problems (NHLBI). See sleep apnea symptoms.
• Other conditions: chronic kidney disease, COPD and other lung problems, and viral infections (NHLBI).
• Alcohol. Drinking large amounts, especially binge drinking, raises the risk. Even modest amounts can trigger AFib in some people (NHLBI).
• Smoking. Many studies link smoking to AFib. The risk seems higher the longer you smoke and goes down if you quit (NHLBI).
• Illegal drugs and stimulants. Cocaine and other street drugs can trigger AFib or make it worse (NHLBI); MedlinePlus also names methamphetamines (MedlinePlus). Many medicines, including over-the-counter ones and stimulants, may raise the risk too, especially if you have other risk factors (NHLBI).
• Very hard exercise. Endurance sports or hard physical work may raise the risk for some people, especially competitive athletes and men. Moderate activity, on the other hand, can help protect against AFib (NHLBI).
• Stress. Stressful situations, panic disorders and other emotional stress may be linked to a higher risk (NHLBI).
• Recent surgery on the heart, lungs or esophagus, in the early days and weeks afterward. Heart surgery for a congenital heart defect can raise the risk even years later (NHLBI).

Race also plays a part. In the United States, AFib is more common in white people than in Black, Hispanic or Asian people. But Black people with AFib are more likely to have serious complications such as stroke and heart failure (NHLBI).

Which ones you can change

What lowers the risk

The NHLBI and MedlinePlus list these steps (NHLBI) (MedlinePlus):

• Heart-healthy habits: aim for a healthy weight, be physically active, control your blood sugar, limit alcohol, lower your blood pressure, manage stress and quit smoking.
• Follow a heart-healthy eating plan (MedlinePlus).
• Avoid illegal drugs such as cocaine and stimulants such as amphetamines.
• Treat any health conditions that could raise your risk (MedlinePlus).
• If you are having heart surgery, your provider may give you medicine for heart rhythm (an antiarrhythmic) to lower the risk.

Why AFib can have no symptoms

You may or may not notice AFib. It often occurs with no symptoms, and some people who have it do not know it (NHLBI) (MedlinePlus). If you have symptoms, they may come only now and then, or they may be frequent or serious. People with heart disease are more likely to notice them (NHLBI). Sometimes AFib goes away on its own; for others it lasts for years, and episodes may come more often and last longer over time (NHLBI).

The most common symptom is fatigue, or extreme tiredness. Others are (NHLBI):

• Heart palpitations: a feeling that your heart is skipping a beat, fluttering, pounding, or beating too hard or too fast
• Trouble breathing, especially when lying down or exercising
• Chest pain
• Dizziness or fainting
• Low blood pressure

Keep track of when your symptoms happen, how often, and what you feel, and tell your provider. These are clues that help diagnose AFib (NHLBI).

Why AFib raises stroke risk

In AFib, blood may pool in the heart. That raises the risk of blood clots, which can lead to a stroke (NHLBI). Untreated AFib can also lead to heart failure, sudden cardiac arrest, and problems with thinking and memory, including dementia (MedlinePlus). Strokes linked to AFib tend to be more severe, and in about 20% of people who have one, the stroke is the first sign that they have AFib (USPSTF 2022).

If you have AFib, doctors use the CHA2DS2-VASc score to judge your stroke risk and whether a blood thinner may help. See CHA2DS2-VASc explained and the stroke risk check.

Stroke signs: call 911. Balance loss, Eye changes, Face drooping, Arm weakness, Speech trouble: Time to call 911 (CDC). More in stroke warning signs.

Should you be screened?

For adults 50 and older without symptoms, the US Preventive Services Task Force found the evidence insufficient to recommend for or against screening for AFib (an I statement) (USPSTF 2022). The AFib screening check explains what that means, including smartwatch alerts. To estimate a 10-year chance of AFib from the Framingham model, try the AFib risk calculator.

Common questions

Can you have AFib and not know it?

Yes. AFib often occurs with no symptoms (NHLBI), which can make it hard to diagnose (NHLBI).

Can a healthy heart get AFib?

Yes. Even in a healthy heart, a fast or slow heart rate, for example from exercise or sleep, can trigger AFib (NHLBI).

Does alcohol cause AFib?

Heavy drinking, especially binge drinking, raises the risk, and even modest amounts can trigger it in some people (NHLBI).