Despite some previous guidance urging caution around caffeine, you may not have to go without your daily cup of joe if you have an irregular heartbeat.
“While the fact that caffeinated coffee appeared to be protective against atrial fibrillation was not terribly surprising given clues from prior observational (or nonrandomized) studies, I was surprised that the magnitude of the apparent benefit was so large,” says study author Gregory Marcus, MD, a professor of medicine and the associate chief of cardiology for research at UCSF Health in San Francisco.
How Coffee and Caffeine Impacted People With Afib
Researchers set out to examine whether drinking caffeinated coffee may have a positive, negative, or neutral impact on recurrent atrial fibrillation (or afib) episodes, which causes an irregular heartbeat.
For this randomized clinical trial, the research team recruited 200 adult participants from five hospitals in the United States, Canada, and Australia. About 7 in 10 were male, and the average age was 69. All had a history of regular coffee drinking and atrial fibrillation.
Over the course of six months, 100 participants were assigned to drink at least one cup of caffeinated coffee daily, while the other 100 were instructed to forgo their daily coffee. Here’s what the findings showed:
- Among the coffee drinkers, atrial fibrillation or flutter occurred in 47 out of 100 participants (47 percent).
- In the group that did not drink coffee, afib or heart flutter occurred in 64 out of 100.
- Rates of hospitalization, heart failure, or stroke were similar in the two groups.
Taken together, the findings suggest that drinking at least one cup of caffeinated coffee per day might reduce the risk of new afib episodes, compared with abstaining from coffee and caffeine altogether.
“This study is surprising in that not only does it not show increased risk of afib after cardioversion with caffeine consumption — it actually shows a 39 percent relative risk reduction in afib recurrence amongst those people who drank at least one cup of coffee a day,” says Omar K. Siddiqi, MD, a clinical associate professor of cardiovascular medicine at Boston University’s Chobanian and Avedisian School of Medicine.
In other words, he says, “Amongst habitual coffee drinkers, continued coffee consumption may actually reduce the risk of afib recurrence.”
Doctors Usually Recommend Caution Around Caffeine for People With Afib
“Caffeinated coffee is the most commonly consumed beverage in the United States, and yet its health effects have generally been understood using suboptimal study designs, namely observational studies — and not randomized trials,” he says.
The new findings align with recent clinical guidelines afib management, which suggest that there isn’t a benefit to avoiding caffeine.
“I think that this study strengthens this current recommendation and argues against recommending routine cessation of caffeinated coffee intake after cardioversion for afib,” Dr. Siddiqi says.
He says it’s still important to talk to your healthcare provider about your specific situation. “If a patient’s arrhythmia is clearly triggered by caffeine, then that person should still limit their caffeine intake,” he says.
The Study Had a Few Limitations
Participants self-reported how much coffee they drank, which can introduce room for error. In addition, the trial only enrolled people with afib who had a history of drinking coffee — which suggests that caffeine tolerance could be at play.
“These findings then are really relevant to those who have previously consumed caffeinated coffee without a problem. That being said, we did not require that individuals were current consumers of caffeinated coffee,” says Marcus. “Many of my patients tell me that they stopped drinking coffee only because some other provider told them to avoid it precisely because of their atrial fibrillation — we wanted to be sure to include those types of patients.”
While the study shows that about one cup of coffee per day doesn’t lead to an increased risk of new afib episodes, Siddiqi says the findings shouldn’t be interpreted too broadly. In other words, if you have afib, don’t go drinking tons of coffee or energy drinks, he says.
“In fact, there are small case series and many case reports to suggest that energy drinks may increase the risk for atrial fibrillation,” he adds.
In addition, the trial was unblinded (meaning that the participants and trial staff knew the treatment assignments) and involved a relatively smaller sample size, which can limit the findings’ applicability.
“Caffeinated coffee almost certainly has many different effects and so it’s important that people understand that it is not necessarily good or bad or healthy or harmful,” says Marcus.“Most conservatively, these data should reassure patients with atrial fibrillation that enjoy drinking caffeinated coffee that it is okay to continue.”