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Study Shows No Need to Shun Coffee to Keep Heart Rhythm Regular

Doctors often tell patients to avoid caffeinated coffee to keep their heart rhythm regular. Studies suggest there's no need to worry.

Coffee has a bad reputation when it comes to irregular heart rhythms. Doctors often tell patients to avoid caffeinated coffee to keep their heart rhythm regular. A few recent studies contradict that conventional wisdom, however (AHA Scientific Sessions 2021, November 14, 2021; JAMA Internal Medicine, online July 19, 2021). Regular coffee drinkers appear less likely to develop arrhythmias.

Does Coffee Trigger Arrhythmias?

Ground or Instant Coffee Drinkers Keep Their Heart Rhythm Regular:

A new study reinforces the health benefits of coffee drinking (European Journal of Preventive Cardiology, Sept. 27, 2022). Investigators analyzed data from the UK Biobank. The roughly 450,000 volunteers answered questions about their coffee drinking behaviors from time to time. Investigators collected data on the participants for more than 12 and a half years.

To many cardiologists’ surprise, people who drank ground or instant coffee up to 5 cups a day had a lower risk of irregular heart rhythms including atrial fibrillation. Those drinking decaf, on the other hand, did not experience this benefit. We are pleased that the scientists asked about decaf coffee consumption, as our readers are interested in the effects of decaf compared to regular coffee.

Notably, those individuals drinking 2 to 3 cups of decaffeinated coffee daily had the lowest risk of cardiovascular disease. Even the people who drank ground or instant coffee had a lower risk of heart attacks or strokes and premature death.

The authors conclude:

“Mild-moderate coffee intake of all types should not be discouraged but rather considered part of a healthy lifestyle.”

Coffee Drinking Linked to PVCs:

Researchers presented intriguing findings at the 2021 American Heart Association Scientific Sessions. The CRAVE study recruited 100 middle-aged volunteers with no history of heart disease or rhythm problems. The protocol randomly assigned participants to drink coffee or avoid it and monitored them to see if they kept their heart rhythm regular.

No volunteer went more than two days without their customary coffee. Each wore a Fitbit to track activity and sleep as well as a continuous electrocardiogram monitor and blood sugar tracking device. When they drank a cup of coffee, they pushed a button on a recording device.  Through this technology, the investigators could ascertain that the volunteers followed their assignments closely.

The results revealed one type of arrhythmia was more common on coffee days:

Coffee had no effect on the upper chamber of the heart. Atrial fibrillation is a serious arrhythmia. Fortunately, it was no more frequent when people were drinking coffee than on caffeine-free days. Investigators noted a common but not worrisome heart irregularity called premature ventricular contraction, or PVC, more often on coffee-consuming days. On coffee-drinking days, people took more steps and spent less time asleep.

In a previous study, researchers had posed this question:

“Is moderate, habitual coffee intake associated with the risk of arrhythmia, and is that association modified by genetic variants that affect caffeine metabolism?”

To answer it, they analyzed data from the UK Biobank over a decade. This review included nearly 400,000 people. Those who usually drank coffee were no more likely to develop rhythm disturbances than those who avoided coffee. In addition, people who are genetically predisposed to metabolize caffeine slowly were no more susceptible to irregular heart rhythms.

Could Coffee Actually Help Keep Your Heart Rhythm Regular?

Even more intriguing, this analysis hints that each additional cup of coffee a person drinks per day lowers the risk of arrhythmias by roughly 3 percent. The authors offer several possible mechanisms, including coffee’s antioxidant and anti-inflammatory properties.

Of course, no one should rely on coffee or caffeine to control heart rhythm irregularities. And some people can’t tolerate coffee at all. But health care professionals should probably revise their unfounded prohibition of coffee to prevent heart rhythm problems.

An invited commentary concludes:

“The current study suggests that we can tell patients that waking up to a cup of coffee is not a dangerous ritual.”

That could come as good news to a person who wrote to us a number of years ago. His wife urged him to shun tea as well as coffee.

Coffee and Atrial Fibrillation:

Does Caffeine Trigger AFib?

Q. Ten years ago I experienced atrial fibrillation three times in one month. It never recurred until recently.

My wife has suggested that I should refrain from eating or drinking anything that contains caffeine. I dislike coffee but I do enjoy drinking good green tea. Does it contain caffeine? How about chocolate? Thanks for your advice.

A. Atrial fibrillation is an irregular heart rhythm that can lead to blood clots in the upper chambers of the heart. That’s why doctors try to reverse the arrhythmia or prescribe blood-thinning medicine.

Your wife’s advice to avoid caffeine is common but unsubstantiated. One epidemiological study found no connection between caffeine consumption and the risk of atrial fib (American Journal of Clinical Nutrition, March, 2005). An experiment in dogs suggested that caffeine might actually be beneficial (Journal of Electrocardiology, Oct. 2006).

Green tea and chocolate both contain much less caffeine than coffee. Moderate consumption should not pose a problem, but do check with your doctor. When you do, have the study from JAMA Internal Medicine at hand. That way, the two of you can determine the best way to keep your heart rhythm regular.

We also heard from a reader who noted that coffee did not interfere with her mother keeping her heart rhythm regular.

Mother Kept Her Heart Rhythm Regular Despite Daily Coffee:

Q. My mom had AFib during the last four years of her life. (She lived to 90!) She was never told to avoid caffeine and enjoyed her ever-important morning coffee throughout those years without a problem.

A. Some doctors have been advising patients with atrial fibrillation (AFib) to avoid coffee and other caffeine-containing products. That advice was not based on evidence, however.
New research confirms that coffee consumption is not associated with atrial fibrillation. Scientists who reported on the CRAVE trial at the American Heart Association Scientific Sessions for 2021 found that people were more likely to experience premature ventricular contractions (PVCs) on days they drank coffee. Unlike atrial fibrillation, however, PVCs are not considered dangerous.

As described above, previous research also found that coffee drinkers were no more likely to experience AFib or other serious rhythm disturbances than those who do not drink it (JAMA Internal Medicine, July 19, 2021). In fact, a Danish study reached that same conclusion more than 15 years ago (American Journal of Clinical Nutrition, March 2005). The Danish Diet, Cancer and Health Study followed up on nearly 48,000 people for more than five years, on average. Those who drank the most coffee were not significantly more likely to develop AFib or atrial flutter than those who drank the least.

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About the Author
Terry Graedon, PhD, is a medical anthropologist and co-host of The People’s Pharmacy radio show, co-author of The People’s Pharmacy syndicated newspaper columns and numerous books, and co-founder of The People’s Pharmacy website. Terry taught in the Duke University School of Nursing and was an adjunct assistant professor in the Department of Anthropology. She is a Fellow of the Society of Applied Anthropology. Terry is one of the country's leading authorities on the science behind folk remedies..
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