In a surprising finding, the first randomized clinical trial revealed that drinking a cup of coffee each day reduces the risk of atrial fibrillation.
Regular coffee consumption may actually help protect against atrial fibrillation (A-Fib), a common heart rhythm problem that causes a fast, irregular heartbeat and can increase the risk of stroke or heart failure.
Although people with heart conditions such as A-Fib are often told to avoid caffeine because it might worsen symptoms, new research suggests the opposite may be true. A collaborative study conducted by the University of California, San Francisco, and the University of Adelaide found that drinking one cup of caffeinated coffee per day lowered the risk of A-Fib by 39%.
“Coffee increases physical activity which is known to reduce atrial fibrillation,” said Gregory M. Marcus, MD, MAS, who holds the Endowed Professorship in Atrial Fibrillation Research and is an electrophysiologist at UCSF Health. Marcus is the senior author of the paper, which was published on November 9 in JAMA.
“Caffeine is also a diuretic, which could potentially reduce blood pressure and in turn lessen A-Fib risk. Several other ingredients in coffee also have anti-inflammatory properties that could have positive effects.”
A Growing Health Concern
Cases of atrial fibrillation have been rising steadily alongside increases in obesity and an aging population. More than 10 million adults in the United States have been diagnosed with A-Fib, and experts estimate that up to one in three people may develop it over their lifetime.
The research team titled their project DECAF, short for Does Eliminating Coffee Avoid Fibrillation? It is the first randomized clinical trial designed to examine the relationship between caffeinated coffee and A-Fib. The study received support from the National Institutes of Health.
The study enrolled 200 coffee-drinking patients with persistent atrial fibrillation, or a related condition called atrial flutter along with a history of A-Fib. They were scheduled for electrical cardioversion, which gives a single electrical shock to shift the heart into a normal rhythm. They were randomly assigned either to consume at least one cup of caffeinated coffee or an espresso shot each day — or abstain from coffee and other products that contain caffeine for six months.
The group that consumed coffee had a 39% lower risk of recurrent A-Fib episodes. In addition to its anti-inflammatory effects, researchers speculated that drinking coffee might also reduce the risk of A-Fib simply by making people consume fewer unhealthy beverages.
“The results were astounding,” said first author Christopher X. Wong, PhD, of UCSF and the University of Adelaide and Royal Adelaide Hospital. “Doctors have always recommended that patients with problematic A-Fib minimize their coffee intake, but this trial suggests that coffee is not only safe but likely to be protective.”
Reference: “Caffeinated Coffee Consumption or Abstinence to Reduce Atrial Fibrillation: The DECAF Randomized Clinical Trial” by Christopher X. Wong, Christopher C. Cheung, Gabrielle Montenegro, Hannah H. Oo, Isabella J. Peña, Janet J. Tang, Samuel J. Tu, Grace Wall, Thomas A. Dewland, Joshua D. Moss, Edward P. Gerstenfeld, Zian H. Tseng, Henry H. Hsia, Randall J. Lee, Jeffrey E. Olgin, Vasanth Vedantham, Melvin M. Scheinman, Catherine Lee, Prashanthan Sanders and Gregory M. Marcus, 9 November 2025, JAMA.
DOI: 10.1001/jama.2025.21056
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