Can You Drink Coffee If You Have AFib?

For years, health professionals have warned people with atrial fibrillation (AFib) to avoid caffeine. Since caffeine is a stimulant, it seemed reasonable to think that it might make AFib worse. 

But over 20 years of medical research tells a different story. In fact, there’s growing evidence that caffeine in moderation might even lower your chances of getting AFib. Here’s what you need to know.

Why are caffeine and AFib even connected?

Many people assume that because caffeine is a stimulant, it must raise your heart rate. This led to the belief that caffeine could trigger AFib. Now we know that’s not correct.

It’s true that like most stimulants, caffeine activates your sympathetic nervous system. In other words, your “fight, flight, or freeze” system is switched on. But it turns out that although caffeine can temporarily raise your blood pressure, it doesn’t usually raise your heart rate. And caffeinated coffee doesn’t usually cause AFib, even in people who drink up to 6 cups per day. 

What’s more, in one study, men who drank 1 to 3 cups of coffee every day had a lower risk of AFib compared to men who drank no coffee at all.

Should you avoid caffeine if you have AFib?

Most people with AFib don’t have to avoid caffeinated coffee. A recent study found that people who had been cardioverted (shocked) out of AFib were actually less likely to go back into AFib if they drank a cup of coffee every day. 

Although this may seem surprising, it’s consistent with other studies on coffee. Less is known about naturally caffeinated tea, but it also seems to be safe in moderation. However, this doesn’t apply to all drinks that contain caffeine. Energy drinks are a different story, which we’ll discuss below.

How much caffeine is safe if you have atrial fibrillation?

As a general rule, it’s best to limit caffeine to 300 mg daily. Some people can drink twice that amount with no problem, and others can’t tolerate any caffeine at all. If you have AFib, it’s important to pay attention to your own body and be aware of what triggers your symptoms. If caffeine gives you palpitations, it’s best to avoid it.

Over time, people tend to build up a tolerance to caffeine. That’s why people who drink a lot of coffee become less sensitive to it.

Caffeine content can vary depending on how drinks are made, but here’s a general guide:

• Brewed coffee (8 oz): 150 mg

• Espresso (1 oz): 50 mg

• Black tea (8 oz): 50 mg

• Green tea (8 oz): 30 mg

Keep in mind that a cup is 8 oz, but many mugs and to-go drinks are 12 oz or more.

Are there caffeinated drinks you should avoid with AFib?

Although coffee (and black or green tea) are generally safe for people at risk for AFib, energy drinks are different. They can definitely raise your heart rate. And they can also put you at risk for serious heart rhythm problems, including AFib. 

The caffeine content in an energy drink is often more than twice that of a cup of coffee. But the risk for AFib is probably related to other stimulants in these products, and not the caffeine alone.

Energy drinks aren’t regulated by the FDA, and ingredient labels may be misleading. Most of the stimulants found in energy drinks — like guarana, taurine, ginseng, and others — haven’t been well studied. Some scientists believe that these stimulants may interact with caffeine in a way that can be risky for the heart. 

Sweetened and caffeinated sodas can also raise your risk of getting AFib. This is true whether they are sugar sweetened or artificially sweetened. We don’t yet know whether highly sweetened coffee drinks affect AFib risk, but it makes sense to limit added sugar.

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Written by:

Sarah A. Samaan, MD

Sarah Samaan, MD, FACC, FACP, FASE is a board-certified cardiologist who practiced clinical cardiology for nearly 30 years. She is a member of the American College of Cardiology and the American College of Physicians, among others.

Edited by:

Katie E. Golden, MD

Katie E. Golden, MD, is a board-certified emergency medicine physician and a medical editor at GoodRx.

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