New research from UC San Francisco and the University of Adelaide reveals that drinking one cup of caffeinated coffee daily may reduce the risk of atrial fibrillation by 39%. This finding challenges long-standing medical advice to avoid caffeine for heart rhythm issues. The DECAF clinical trial provides the first randomized evidence supporting coffee's potential benefits for heart health.
Atrial fibrillation (AFib), a common heart rhythm disorder that can lead to stroke or heart failure, affects over 10 million adults in the United States, with rates rising due to aging populations and obesity. For decades, doctors have cautioned patients with AFib to limit caffeine intake, fearing it might exacerbate symptoms. However, a groundbreaking study published on November 9, 2025, in JAMA overturns this view.
The DECAF trial (Does Eliminating Coffee Avoid Fibrillation?), funded by the National Institutes of Health, is the first randomized clinical trial examining caffeinated coffee's impact on AFib. It involved 200 regular coffee drinkers with persistent AFib or atrial flutter and a history of the condition, all scheduled for electrical cardioversion—a procedure using controlled shocks to restore normal heart rhythm.
Participants were randomly assigned to two groups for six months: one continued drinking at least one cup of caffeinated coffee or an espresso shot daily, while the other abstained from all caffeinated beverages. The coffee-drinking group showed a 39% lower risk of AFib recurrence compared to the abstainers.
"Coffee increases physical activity which is known to reduce atrial fibrillation," explained senior author Gregory M. Marcus, MD, MAS, an electrophysiologist at UCSF Health. He noted that caffeine acts as a diuretic, potentially lowering blood pressure, and coffee's other ingredients offer anti-inflammatory benefits. Researchers also suggested coffee drinkers might replace sugary sodas with healthier options.
"The results were astounding," said lead author Christopher X. Wong, PhD, from UCSF, the University of Adelaide, and the Royal Adelaide Hospital. "Doctors have always recommended that patients with problematic AFib minimize their coffee intake, but this trial suggests that coffee is not only safe but likely to be protective."
The study, involving multiple UCSF authors including Thomas A. Dewland, MD, and Jeffrey E. Olgin, MD, highlights coffee's role in promoting physical activity, reducing inflammation, and supporting heart rhythm stability.